In [65]:
import numpy as np

In [66]:
# Let's test some linear algebra tools starting with a randomly populated 100x3 array
X = np.random.random((100,3))
# Exercise: What is the shape of this?
X.shape
X.mean()

In [67]:
# Covariance of centered data (X^T X)/sqrt(N-1)
Cx = np.dot(X.T, X)
Cx

In [68]:
# Compute the singular value decomposition of the data matrix
# We can compute PCA through the eigenvalue decomposition of the covariance matrix (or SVD)
left_singular_vec, singular_vals, right_singular_vec = np.linalg.svd(X)
# Exercise: Use help menu and/or google to determine what these values are.
singular_vals**2

In [69]:
# Get the eigenvalues and eigenvectors
eigval, eigvec = np.linalg.eigh(Cx)
print "eigenvectors"
print eigvec 
print " "
print "eigenvals", eigval


eigenvectors
[[-0.81693014 -0.10240483 -0.56757237]
 [ 0.48494308 -0.65464986 -0.57988255]
 [ 0.3121784   0.74896383 -0.58446371]]
 
eigenvals [  6.15937334  10.2948743   80.04132454]

In [70]:
# Exercise: Compare eigenvalues to singular values given the relationwhip between SVD
# and the covariance matrix.
singular_vals**2


Out[70]:
array([ 80.04132454,  10.2948743 ,   6.15937334])

PCA Exercise


In [71]:
from sklearn.decomposition import PCA

In [72]:
# Generate a 10-d array with 5 intrinsic dimensions
X3d = np.random.normal(size=(100,3))
R = np.random.random((3,10)) # Projection matrix
X10d = np.dot(X, R)

In [73]:
# Run pca
pca = PCA(n_components=5)
pca.fit(X10d)


Out[73]:
PCA(copy=True, iterated_power='auto', n_components=5, random_state=None,
  svd_solver='auto', tol=0.0, whiten=False)

In [74]:
# compute subspace
pca.transform(X10d)


Out[74]:
array([[  1.85478506e-01,  -2.56836883e-01,  -4.27431021e-02,
          3.29597460e-16],
       [ -7.39964058e-01,   4.81934056e-02,  -4.93613768e-01,
          2.35922393e-16],
       [ -1.04231609e+00,   2.35023091e-01,   5.77602644e-02,
          3.05311332e-16],
       [  1.32169068e+00,  -2.64010992e-01,   3.11709795e-02,
          4.99600361e-16],
       [  5.15939516e-01,  -4.67267650e-01,  -1.91506520e-01,
          3.53883589e-16],
       [  3.74180408e-01,  -1.57247976e-01,  -2.04189504e-01,
          3.67761377e-16],
       [  1.08116439e+00,   6.92150667e-02,   2.07138745e-01,
          4.99600361e-16],
       [ -4.14290805e-01,   2.14089360e-01,  -3.33925248e-01,
          2.77555756e-16],
       [ -3.55367931e-01,   3.17792078e-01,   3.33961625e-01,
          2.92300906e-16],
       [ -7.95197221e-01,  -7.77367892e-02,   1.78993876e-02,
          4.02455846e-16],
       [ -2.55496875e-01,   4.01462178e-01,  -3.31287569e-02,
          3.60822483e-16],
       [ -7.51521111e-01,  -3.19933628e-01,   1.17951461e-01,
          3.67761377e-16],
       [  4.63875082e-01,   3.32815688e-01,   1.61695931e-01,
          5.62050406e-16],
       [  5.53635168e-01,   3.04688718e-01,   4.75531580e-02,
          4.44089210e-16],
       [  4.34359585e-01,  -4.79142129e-02,   4.19874328e-01,
          4.44089210e-16],
       [ -1.15907714e+00,  -5.38622817e-01,   2.03204566e-01,
          1.94289029e-16],
       [  1.08566663e+00,   3.23232063e-01,  -1.76334095e-01,
          5.27355937e-16],
       [ -6.64579700e-01,   5.42477429e-01,   2.13761296e-01,
          4.23272528e-16],
       [  3.08302966e-01,   6.10701279e-01,  -7.65256458e-02,
          4.33680869e-16],
       [  4.07069249e-04,   3.07712935e-01,  -7.04955832e-02,
          4.31946146e-16],
       [ -3.27843581e-01,   4.41921696e-01,   1.52608512e-01,
          2.98372438e-16],
       [ -1.71776218e+00,   2.36562153e-01,   5.89562175e-02,
          4.44089210e-16],
       [ -1.42776737e+00,   1.26741200e-01,   1.99129776e-02,
          2.22044605e-16],
       [ -1.10228330e+00,   1.95445107e-01,  -2.41165336e-01,
          2.77555756e-16],
       [ -7.48555721e-01,   6.84648887e-02,  -3.11099453e-01,
          3.19189120e-16],
       [ -8.10375029e-01,  -5.00767869e-02,  -2.11665555e-01,
          3.60822483e-16],
       [ -4.65633855e-01,   2.51769164e-01,  -2.74788394e-01,
          3.05311332e-16],
       [  6.66037799e-01,   2.90526734e-01,  -9.45525033e-02,
          4.30211422e-16],
       [ -4.70931739e-01,  -4.39125898e-01,  -2.11407871e-02,
          4.09394740e-16],
       [ -8.68087057e-01,  -9.15320314e-02,  -8.57230408e-02,
          2.77555756e-16],
       [ -8.53039793e-02,  -1.50545539e-01,  -6.72564714e-02,
          3.76434994e-16],
       [ -1.48990555e+00,   1.41976084e-01,  -1.85411600e-01,
          2.77555756e-16],
       [  8.13103143e-01,   1.44243855e-01,  -1.38360686e-01,
          3.74700271e-16],
       [ -1.84913906e+00,   3.34666909e-04,  -1.15859818e-01,
          3.05311332e-16],
       [  1.91275597e-01,  -3.38801201e-01,   1.88152535e-02,
          4.51028104e-16],
       [ -3.22808324e-01,   3.27597002e-01,   2.80002113e-01,
          4.04190570e-16],
       [ -1.09751373e+00,  -2.02210336e-01,   1.11785358e-01,
          4.57966998e-16],
       [  5.59325662e-01,   6.45297848e-01,  -1.52631890e-01,
          3.81639165e-16],
       [ -1.93650265e+00,  -5.03675568e-02,   8.22945897e-02,
          1.66533454e-16],
       [ -3.96660773e-01,  -3.29595406e-01,   1.39005358e-01,
          4.05925293e-16],
       [ -7.73700127e-01,  -4.20814388e-01,   3.00898336e-02,
          3.60822483e-16],
       [  6.42569916e-01,  -4.09365974e-02,  -1.34137789e-01,
          5.27355937e-16],
       [  4.75588995e-01,  -2.69772437e-01,  -1.76445097e-02,
          4.57966998e-16],
       [  6.14977006e-01,  -5.61997738e-01,  -2.02393862e-01,
          4.78783679e-16],
       [  7.64853509e-01,   1.42696063e-01,   4.34419484e-02,
          4.44089210e-16],
       [  1.28506136e+00,  -3.47005327e-01,  -1.67891938e-01,
          4.57966998e-16],
       [  8.40219534e-01,   3.19320751e-02,  -1.34529363e-01,
          4.30211422e-16],
       [  8.05487807e-01,   5.94892247e-02,  -1.79110656e-01,
          4.92661467e-16],
       [ -6.81948914e-01,  -5.93571639e-02,  -5.53968723e-02,
          2.77555756e-16],
       [ -7.04666788e-01,   6.96250011e-02,  -9.54453174e-02,
          4.02455846e-16],
       [ -4.99143670e-01,   6.90707096e-02,   8.54211796e-02,
          3.67761377e-16],
       [ -1.09086856e-01,  -2.75547255e-01,   3.71826205e-01,
          4.33680869e-16],
       [  9.87480440e-01,  -3.91573681e-01,  -3.52219468e-02,
          3.88578059e-16],
       [  1.46657385e+00,   1.97970036e-01,  -8.41950808e-02,
          4.71844785e-16],
       [  2.98843705e-01,  -2.49138996e-01,  -3.19775318e-01,
          3.27212216e-16],
       [ -1.46826249e+00,  -7.02002619e-02,  -1.17784589e-01,
          3.60822483e-16],
       [ -3.44191901e-01,  -2.21604755e-01,   5.01873685e-02,
          3.57353036e-16],
       [  1.09989391e+00,   5.16426330e-02,   1.32152797e-01,
          5.13478149e-16],
       [ -7.25759660e-01,   2.10182760e-01,  -1.73334321e-01,
          3.05311332e-16],
       [ -5.51154170e-01,  -2.00039061e-01,   2.27596787e-01,
          4.68375339e-16],
       [ -4.85195391e-01,   3.46447827e-01,   7.61986308e-02,
          3.81639165e-16],
       [  3.07688376e-01,   4.40932882e-01,  -1.43775301e-01,
          3.71230824e-16],
       [ -5.58215588e-02,  -3.09944556e-01,  -2.22973512e-02,
          4.04190570e-16],
       [ -1.17031351e-02,   3.14719371e-01,   4.81707897e-02,
          4.46691295e-16],
       [  7.20296625e-01,   7.59040409e-02,   9.61594747e-02,
          4.44089210e-16],
       [  2.70890723e-01,   4.25190033e-01,   1.38686836e-01,
          4.16333634e-16],
       [  2.10776680e+00,  -1.24666430e-01,  -8.25663333e-02,
          4.99600361e-16],
       [  3.30349804e-01,  -2.63019256e-01,   2.34617414e-01,
          4.51028104e-16],
       [  1.21073137e+00,   3.55063388e-01,  -8.99864732e-02,
          4.02455846e-16],
       [  1.42194237e+00,  -6.63865125e-02,   2.03143199e-01,
          4.71844785e-16],
       [  1.98096991e-01,  -4.76684421e-01,  -8.47382276e-02,
          4.54497551e-16],
       [ -4.96584222e-01,  -5.29856638e-01,   1.25208689e-01,
          4.09394740e-16],
       [ -6.49896194e-01,   1.14517026e-01,   4.51247289e-02,
          4.23272528e-16],
       [  6.16490813e-02,   5.02916707e-01,  -3.46062290e-03,
          3.75025531e-16],
       [  9.43398031e-01,  -2.58387814e-01,  -1.45005944e-02,
          4.57966998e-16],
       [  6.86415859e-01,  -3.55352066e-01,   4.69478270e-02,
          4.44089210e-16],
       [  2.15464316e+00,  -3.22887634e-02,  -6.15819145e-02,
          5.55111512e-16],
       [ -1.26751239e+00,  -2.60566875e-01,   8.66350369e-02,
          1.80411242e-16],
       [  4.87019022e-01,  -2.92933342e-01,  -2.09220295e-01,
          4.64905892e-16],
       [ -3.36503667e-02,  -3.79741499e-01,  -1.37653053e-01,
          4.23272528e-16],
       [  5.88395671e-01,   2.37869964e-01,   9.56393799e-02,
          4.99600361e-16],
       [  2.15504899e-01,   1.06771806e-01,   2.36231860e-01,
          3.88578059e-16],
       [ -1.43409478e-01,  -4.22129468e-01,  -2.12531015e-01,
          4.44089210e-16],
       [ -5.98486876e-01,   5.29065538e-01,   3.06516539e-01,
          4.37150316e-16],
       [  9.84899610e-02,  -1.56039080e-01,   2.59013161e-02,
          4.21537805e-16],
       [  1.12039600e-01,   4.05234844e-01,   1.01707987e-02,
          4.38017678e-16],
       [ -1.10905510e+00,  -3.02319984e-01,  -1.05548375e-02,
          4.44089210e-16],
       [  1.09881542e+00,   9.59811537e-02,   9.75268541e-02,
          4.57966998e-16],
       [  2.76189183e-01,   3.01455296e-01,   2.46659654e-02,
          4.19803081e-16],
       [  3.85997622e-01,  -1.39547792e-01,   1.16204562e-01,
          5.20417043e-16],
       [ -1.48700178e+00,   3.69025193e-01,   1.80665487e-01,
          3.60822483e-16],
       [ -5.26991272e-01,  -5.76589371e-01,   2.25427596e-01,
          4.78783679e-16],
       [  1.67199125e+00,  -4.40222048e-02,   1.81871159e-01,
          5.55111512e-16],
       [  1.85347375e+00,   1.92557343e-02,  -5.40723598e-02,
          4.99600361e-16],
       [ -9.00163790e-01,   1.56929068e-01,  -3.10257448e-01,
          3.33066907e-16],
       [  4.86540102e-01,   6.94088032e-02,   9.08231780e-02,
          5.20417043e-16],
       [ -8.81780784e-01,  -1.92990356e-01,   7.19507470e-02,
          4.16333634e-16],
       [ -2.61108496e-01,   3.47564099e-01,  -1.15293852e-01,
          3.67761377e-16],
       [  8.51897874e-01,   7.48559027e-02,   2.65371130e-01,
          5.27355937e-16],
       [ -3.15055551e-01,  -6.26721075e-01,   1.45541563e-01,
          2.65412692e-16]])

In [75]:
# Mean of the data in 10-d
pca.mean_


Out[75]:
array([ 1.01864848,  0.70057024,  0.44218263,  0.61671891,  0.4222405 ,
        0.72191211,  1.18002049,  0.43724834,  0.55705748,  1.11432514])

In [76]:
pca.explained_variance_
# Exercise: Explain the last value.  Hint: Play with the n_components kwarg.


Out[76]:
array([  7.77366287e-01,   9.09282304e-02,   2.83171107e-02,
         1.65675676e-31])

In [77]:
help(pca.explained_variance_)


Help on ndarray object:

class ndarray(__builtin__.object)
 |  ndarray(shape, dtype=float, buffer=None, offset=0,
 |          strides=None, order=None)
 |  
 |  An array object represents a multidimensional, homogeneous array
 |  of fixed-size items.  An associated data-type object describes the
 |  format of each element in the array (its byte-order, how many bytes it
 |  occupies in memory, whether it is an integer, a floating point number,
 |  or something else, etc.)
 |  
 |  Arrays should be constructed using `array`, `zeros` or `empty` (refer
 |  to the See Also section below).  The parameters given here refer to
 |  a low-level method (`ndarray(...)`) for instantiating an array.
 |  
 |  For more information, refer to the `numpy` module and examine the
 |  the methods and attributes of an array.
 |  
 |  Parameters
 |  ----------
 |  (for the __new__ method; see Notes below)
 |  
 |  shape : tuple of ints
 |      Shape of created array.
 |  dtype : data-type, optional
 |      Any object that can be interpreted as a numpy data type.
 |  buffer : object exposing buffer interface, optional
 |      Used to fill the array with data.
 |  offset : int, optional
 |      Offset of array data in buffer.
 |  strides : tuple of ints, optional
 |      Strides of data in memory.
 |  order : {'C', 'F'}, optional
 |      Row-major (C-style) or column-major (Fortran-style) order.
 |  
 |  Attributes
 |  ----------
 |  T : ndarray
 |      Transpose of the array.
 |  data : buffer
 |      The array's elements, in memory.
 |  dtype : dtype object
 |      Describes the format of the elements in the array.
 |  flags : dict
 |      Dictionary containing information related to memory use, e.g.,
 |      'C_CONTIGUOUS', 'OWNDATA', 'WRITEABLE', etc.
 |  flat : numpy.flatiter object
 |      Flattened version of the array as an iterator.  The iterator
 |      allows assignments, e.g., ``x.flat = 3`` (See `ndarray.flat` for
 |      assignment examples; TODO).
 |  imag : ndarray
 |      Imaginary part of the array.
 |  real : ndarray
 |      Real part of the array.
 |  size : int
 |      Number of elements in the array.
 |  itemsize : int
 |      The memory use of each array element in bytes.
 |  nbytes : int
 |      The total number of bytes required to store the array data,
 |      i.e., ``itemsize * size``.
 |  ndim : int
 |      The array's number of dimensions.
 |  shape : tuple of ints
 |      Shape of the array.
 |  strides : tuple of ints
 |      The step-size required to move from one element to the next in
 |      memory. For example, a contiguous ``(3, 4)`` array of type
 |      ``int16`` in C-order has strides ``(8, 2)``.  This implies that
 |      to move from element to element in memory requires jumps of 2 bytes.
 |      To move from row-to-row, one needs to jump 8 bytes at a time
 |      (``2 * 4``).
 |  ctypes : ctypes object
 |      Class containing properties of the array needed for interaction
 |      with ctypes.
 |  base : ndarray
 |      If the array is a view into another array, that array is its `base`
 |      (unless that array is also a view).  The `base` array is where the
 |      array data is actually stored.
 |  
 |  See Also
 |  --------
 |  array : Construct an array.
 |  zeros : Create an array, each element of which is zero.
 |  empty : Create an array, but leave its allocated memory unchanged (i.e.,
 |          it contains "garbage").
 |  dtype : Create a data-type.
 |  
 |  Notes
 |  -----
 |  There are two modes of creating an array using ``__new__``:
 |  
 |  1. If `buffer` is None, then only `shape`, `dtype`, and `order`
 |     are used.
 |  2. If `buffer` is an object exposing the buffer interface, then
 |     all keywords are interpreted.
 |  
 |  No ``__init__`` method is needed because the array is fully initialized
 |  after the ``__new__`` method.
 |  
 |  Examples
 |  --------
 |  These examples illustrate the low-level `ndarray` constructor.  Refer
 |  to the `See Also` section above for easier ways of constructing an
 |  ndarray.
 |  
 |  First mode, `buffer` is None:
 |  
 |  >>> np.ndarray(shape=(2,2), dtype=float, order='F')
 |  array([[ -1.13698227e+002,   4.25087011e-303],
 |         [  2.88528414e-306,   3.27025015e-309]])         #random
 |  
 |  Second mode:
 |  
 |  >>> np.ndarray((2,), buffer=np.array([1,2,3]),
 |  ...            offset=np.int_().itemsize,
 |  ...            dtype=int) # offset = 1*itemsize, i.e. skip first element
 |  array([2, 3])
 |  
 |  Methods defined here:
 |  
 |  __abs__(...)
 |      x.__abs__() <==> abs(x)
 |  
 |  __add__(...)
 |      x.__add__(y) <==> x+y
 |  
 |  __and__(...)
 |      x.__and__(y) <==> x&y
 |  
 |  __array__(...)
 |      a.__array__(|dtype) -> reference if type unchanged, copy otherwise.
 |      
 |      Returns either a new reference to self if dtype is not given or a new array
 |      of provided data type if dtype is different from the current dtype of the
 |      array.
 |  
 |  __array_prepare__(...)
 |      a.__array_prepare__(obj) -> Object of same type as ndarray object obj.
 |  
 |  __array_wrap__(...)
 |      a.__array_wrap__(obj) -> Object of same type as ndarray object a.
 |  
 |  __contains__(...)
 |      x.__contains__(y) <==> y in x
 |  
 |  __copy__(...)
 |      a.__copy__([order])
 |      
 |      Return a copy of the array.
 |      
 |      Parameters
 |      ----------
 |      order : {'C', 'F', 'A'}, optional
 |          If order is 'C' (False) then the result is contiguous (default).
 |          If order is 'Fortran' (True) then the result has fortran order.
 |          If order is 'Any' (None) then the result has fortran order
 |          only if the array already is in fortran order.
 |  
 |  __deepcopy__(...)
 |      a.__deepcopy__() -> Deep copy of array.
 |      
 |      Used if copy.deepcopy is called on an array.
 |  
 |  __delitem__(...)
 |      x.__delitem__(y) <==> del x[y]
 |  
 |  __delslice__(...)
 |      x.__delslice__(i, j) <==> del x[i:j]
 |      
 |      Use of negative indices is not supported.
 |  
 |  __div__(...)
 |      x.__div__(y) <==> x/y
 |  
 |  __divmod__(...)
 |      x.__divmod__(y) <==> divmod(x, y)
 |  
 |  __eq__(...)
 |      x.__eq__(y) <==> x==y
 |  
 |  __float__(...)
 |      x.__float__() <==> float(x)
 |  
 |  __floordiv__(...)
 |      x.__floordiv__(y) <==> x//y
 |  
 |  __ge__(...)
 |      x.__ge__(y) <==> x>=y
 |  
 |  __getitem__(...)
 |      x.__getitem__(y) <==> x[y]
 |  
 |  __getslice__(...)
 |      x.__getslice__(i, j) <==> x[i:j]
 |      
 |      Use of negative indices is not supported.
 |  
 |  __gt__(...)
 |      x.__gt__(y) <==> x>y
 |  
 |  __hex__(...)
 |      x.__hex__() <==> hex(x)
 |  
 |  __iadd__(...)
 |      x.__iadd__(y) <==> x+=y
 |  
 |  __iand__(...)
 |      x.__iand__(y) <==> x&=y
 |  
 |  __idiv__(...)
 |      x.__idiv__(y) <==> x/=y
 |  
 |  __ifloordiv__(...)
 |      x.__ifloordiv__(y) <==> x//=y
 |  
 |  __ilshift__(...)
 |      x.__ilshift__(y) <==> x<<=y
 |  
 |  __imod__(...)
 |      x.__imod__(y) <==> x%=y
 |  
 |  __imul__(...)
 |      x.__imul__(y) <==> x*=y
 |  
 |  __index__(...)
 |      x[y:z] <==> x[y.__index__():z.__index__()]
 |  
 |  __int__(...)
 |      x.__int__() <==> int(x)
 |  
 |  __invert__(...)
 |      x.__invert__() <==> ~x
 |  
 |  __ior__(...)
 |      x.__ior__(y) <==> x|=y
 |  
 |  __ipow__(...)
 |      x.__ipow__(y) <==> x**=y
 |  
 |  __irshift__(...)
 |      x.__irshift__(y) <==> x>>=y
 |  
 |  __isub__(...)
 |      x.__isub__(y) <==> x-=y
 |  
 |  __iter__(...)
 |      x.__iter__() <==> iter(x)
 |  
 |  __itruediv__(...)
 |      x.__itruediv__(y) <==> x/=y
 |  
 |  __ixor__(...)
 |      x.__ixor__(y) <==> x^=y
 |  
 |  __le__(...)
 |      x.__le__(y) <==> x<=y
 |  
 |  __len__(...)
 |      x.__len__() <==> len(x)
 |  
 |  __long__(...)
 |      x.__long__() <==> long(x)
 |  
 |  __lshift__(...)
 |      x.__lshift__(y) <==> x<<y
 |  
 |  __lt__(...)
 |      x.__lt__(y) <==> x<y
 |  
 |  __mod__(...)
 |      x.__mod__(y) <==> x%y
 |  
 |  __mul__(...)
 |      x.__mul__(y) <==> x*y
 |  
 |  __ne__(...)
 |      x.__ne__(y) <==> x!=y
 |  
 |  __neg__(...)
 |      x.__neg__() <==> -x
 |  
 |  __nonzero__(...)
 |      x.__nonzero__() <==> x != 0
 |  
 |  __oct__(...)
 |      x.__oct__() <==> oct(x)
 |  
 |  __or__(...)
 |      x.__or__(y) <==> x|y
 |  
 |  __pos__(...)
 |      x.__pos__() <==> +x
 |  
 |  __pow__(...)
 |      x.__pow__(y[, z]) <==> pow(x, y[, z])
 |  
 |  __radd__(...)
 |      x.__radd__(y) <==> y+x
 |  
 |  __rand__(...)
 |      x.__rand__(y) <==> y&x
 |  
 |  __rdiv__(...)
 |      x.__rdiv__(y) <==> y/x
 |  
 |  __rdivmod__(...)
 |      x.__rdivmod__(y) <==> divmod(y, x)
 |  
 |  __reduce__(...)
 |      a.__reduce__()
 |      
 |      For pickling.
 |  
 |  __repr__(...)
 |      x.__repr__() <==> repr(x)
 |  
 |  __rfloordiv__(...)
 |      x.__rfloordiv__(y) <==> y//x
 |  
 |  __rlshift__(...)
 |      x.__rlshift__(y) <==> y<<x
 |  
 |  __rmod__(...)
 |      x.__rmod__(y) <==> y%x
 |  
 |  __rmul__(...)
 |      x.__rmul__(y) <==> y*x
 |  
 |  __ror__(...)
 |      x.__ror__(y) <==> y|x
 |  
 |  __rpow__(...)
 |      y.__rpow__(x[, z]) <==> pow(x, y[, z])
 |  
 |  __rrshift__(...)
 |      x.__rrshift__(y) <==> y>>x
 |  
 |  __rshift__(...)
 |      x.__rshift__(y) <==> x>>y
 |  
 |  __rsub__(...)
 |      x.__rsub__(y) <==> y-x
 |  
 |  __rtruediv__(...)
 |      x.__rtruediv__(y) <==> y/x
 |  
 |  __rxor__(...)
 |      x.__rxor__(y) <==> y^x
 |  
 |  __setitem__(...)
 |      x.__setitem__(i, y) <==> x[i]=y
 |  
 |  __setslice__(...)
 |      x.__setslice__(i, j, y) <==> x[i:j]=y
 |      
 |      Use  of negative indices is not supported.
 |  
 |  __setstate__(...)
 |      a.__setstate__(version, shape, dtype, isfortran, rawdata)
 |      
 |      For unpickling.
 |      
 |      Parameters
 |      ----------
 |      version : int
 |          optional pickle version. If omitted defaults to 0.
 |      shape : tuple
 |      dtype : data-type
 |      isFortran : bool
 |      rawdata : string or list
 |          a binary string with the data (or a list if 'a' is an object array)
 |  
 |  __sizeof__(...)
 |  
 |  __str__(...)
 |      x.__str__() <==> str(x)
 |  
 |  __sub__(...)
 |      x.__sub__(y) <==> x-y
 |  
 |  __truediv__(...)
 |      x.__truediv__(y) <==> x/y
 |  
 |  __xor__(...)
 |      x.__xor__(y) <==> x^y
 |  
 |  all(...)
 |      a.all(axis=None, out=None, keepdims=False)
 |      
 |      Returns True if all elements evaluate to True.
 |      
 |      Refer to `numpy.all` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.all : equivalent function
 |  
 |  any(...)
 |      a.any(axis=None, out=None, keepdims=False)
 |      
 |      Returns True if any of the elements of `a` evaluate to True.
 |      
 |      Refer to `numpy.any` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.any : equivalent function
 |  
 |  argmax(...)
 |      a.argmax(axis=None, out=None)
 |      
 |      Return indices of the maximum values along the given axis.
 |      
 |      Refer to `numpy.argmax` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.argmax : equivalent function
 |  
 |  argmin(...)
 |      a.argmin(axis=None, out=None)
 |      
 |      Return indices of the minimum values along the given axis of `a`.
 |      
 |      Refer to `numpy.argmin` for detailed documentation.
 |      
 |      See Also
 |      --------
 |      numpy.argmin : equivalent function
 |  
 |  argpartition(...)
 |      a.argpartition(kth, axis=-1, kind='introselect', order=None)
 |      
 |      Returns the indices that would partition this array.
 |      
 |      Refer to `numpy.argpartition` for full documentation.
 |      
 |      .. versionadded:: 1.8.0
 |      
 |      See Also
 |      --------
 |      numpy.argpartition : equivalent function
 |  
 |  argsort(...)
 |      a.argsort(axis=-1, kind='quicksort', order=None)
 |      
 |      Returns the indices that would sort this array.
 |      
 |      Refer to `numpy.argsort` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.argsort : equivalent function
 |  
 |  astype(...)
 |      a.astype(dtype, order='K', casting='unsafe', subok=True, copy=True)
 |      
 |      Copy of the array, cast to a specified type.
 |      
 |      Parameters
 |      ----------
 |      dtype : str or dtype
 |          Typecode or data-type to which the array is cast.
 |      order : {'C', 'F', 'A', 'K'}, optional
 |          Controls the memory layout order of the result.
 |          'C' means C order, 'F' means Fortran order, 'A'
 |          means 'F' order if all the arrays are Fortran contiguous,
 |          'C' order otherwise, and 'K' means as close to the
 |          order the array elements appear in memory as possible.
 |          Default is 'K'.
 |      casting : {'no', 'equiv', 'safe', 'same_kind', 'unsafe'}, optional
 |          Controls what kind of data casting may occur. Defaults to 'unsafe'
 |          for backwards compatibility.
 |      
 |            * 'no' means the data types should not be cast at all.
 |            * 'equiv' means only byte-order changes are allowed.
 |            * 'safe' means only casts which can preserve values are allowed.
 |            * 'same_kind' means only safe casts or casts within a kind,
 |              like float64 to float32, are allowed.
 |            * 'unsafe' means any data conversions may be done.
 |      subok : bool, optional
 |          If True, then sub-classes will be passed-through (default), otherwise
 |          the returned array will be forced to be a base-class array.
 |      copy : bool, optional
 |          By default, astype always returns a newly allocated array. If this
 |          is set to false, and the `dtype`, `order`, and `subok`
 |          requirements are satisfied, the input array is returned instead
 |          of a copy.
 |      
 |      Returns
 |      -------
 |      arr_t : ndarray
 |          Unless `copy` is False and the other conditions for returning the input
 |          array are satisfied (see description for `copy` input paramter), `arr_t`
 |          is a new array of the same shape as the input array, with dtype, order
 |          given by `dtype`, `order`.
 |      
 |      Notes
 |      -----
 |      Starting in NumPy 1.9, astype method now returns an error if the string
 |      dtype to cast to is not long enough in 'safe' casting mode to hold the max
 |      value of integer/float array that is being casted. Previously the casting
 |      was allowed even if the result was truncated.
 |      
 |      Raises
 |      ------
 |      ComplexWarning
 |          When casting from complex to float or int. To avoid this,
 |          one should use ``a.real.astype(t)``.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([1, 2, 2.5])
 |      >>> x
 |      array([ 1. ,  2. ,  2.5])
 |      
 |      >>> x.astype(int)
 |      array([1, 2, 2])
 |  
 |  byteswap(...)
 |      a.byteswap(inplace)
 |      
 |      Swap the bytes of the array elements
 |      
 |      Toggle between low-endian and big-endian data representation by
 |      returning a byteswapped array, optionally swapped in-place.
 |      
 |      Parameters
 |      ----------
 |      inplace : bool, optional
 |          If ``True``, swap bytes in-place, default is ``False``.
 |      
 |      Returns
 |      -------
 |      out : ndarray
 |          The byteswapped array. If `inplace` is ``True``, this is
 |          a view to self.
 |      
 |      Examples
 |      --------
 |      >>> A = np.array([1, 256, 8755], dtype=np.int16)
 |      >>> map(hex, A)
 |      ['0x1', '0x100', '0x2233']
 |      >>> A.byteswap(True)
 |      array([  256,     1, 13090], dtype=int16)
 |      >>> map(hex, A)
 |      ['0x100', '0x1', '0x3322']
 |      
 |      Arrays of strings are not swapped
 |      
 |      >>> A = np.array(['ceg', 'fac'])
 |      >>> A.byteswap()
 |      array(['ceg', 'fac'],
 |            dtype='|S3')
 |  
 |  choose(...)
 |      a.choose(choices, out=None, mode='raise')
 |      
 |      Use an index array to construct a new array from a set of choices.
 |      
 |      Refer to `numpy.choose` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.choose : equivalent function
 |  
 |  clip(...)
 |      a.clip(min=None, max=None, out=None)
 |      
 |      Return an array whose values are limited to ``[min, max]``.
 |      One of max or min must be given.
 |      
 |      Refer to `numpy.clip` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.clip : equivalent function
 |  
 |  compress(...)
 |      a.compress(condition, axis=None, out=None)
 |      
 |      Return selected slices of this array along given axis.
 |      
 |      Refer to `numpy.compress` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.compress : equivalent function
 |  
 |  conj(...)
 |      a.conj()
 |      
 |      Complex-conjugate all elements.
 |      
 |      Refer to `numpy.conjugate` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.conjugate : equivalent function
 |  
 |  conjugate(...)
 |      a.conjugate()
 |      
 |      Return the complex conjugate, element-wise.
 |      
 |      Refer to `numpy.conjugate` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.conjugate : equivalent function
 |  
 |  copy(...)
 |      a.copy(order='C')
 |      
 |      Return a copy of the array.
 |      
 |      Parameters
 |      ----------
 |      order : {'C', 'F', 'A', 'K'}, optional
 |          Controls the memory layout of the copy. 'C' means C-order,
 |          'F' means F-order, 'A' means 'F' if `a` is Fortran contiguous,
 |          'C' otherwise. 'K' means match the layout of `a` as closely
 |          as possible. (Note that this function and :func:numpy.copy are very
 |          similar, but have different default values for their order=
 |          arguments.)
 |      
 |      See also
 |      --------
 |      numpy.copy
 |      numpy.copyto
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([[1,2,3],[4,5,6]], order='F')
 |      
 |      >>> y = x.copy()
 |      
 |      >>> x.fill(0)
 |      
 |      >>> x
 |      array([[0, 0, 0],
 |             [0, 0, 0]])
 |      
 |      >>> y
 |      array([[1, 2, 3],
 |             [4, 5, 6]])
 |      
 |      >>> y.flags['C_CONTIGUOUS']
 |      True
 |  
 |  cumprod(...)
 |      a.cumprod(axis=None, dtype=None, out=None)
 |      
 |      Return the cumulative product of the elements along the given axis.
 |      
 |      Refer to `numpy.cumprod` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.cumprod : equivalent function
 |  
 |  cumsum(...)
 |      a.cumsum(axis=None, dtype=None, out=None)
 |      
 |      Return the cumulative sum of the elements along the given axis.
 |      
 |      Refer to `numpy.cumsum` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.cumsum : equivalent function
 |  
 |  diagonal(...)
 |      a.diagonal(offset=0, axis1=0, axis2=1)
 |      
 |      Return specified diagonals. In NumPy 1.9 the returned array is a
 |      read-only view instead of a copy as in previous NumPy versions.  In
 |      NumPy 1.10 the read-only restriction will be removed.
 |      
 |      Refer to :func:`numpy.diagonal` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.diagonal : equivalent function
 |  
 |  dot(...)
 |      a.dot(b, out=None)
 |      
 |      Dot product of two arrays.
 |      
 |      Refer to `numpy.dot` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.dot : equivalent function
 |      
 |      Examples
 |      --------
 |      >>> a = np.eye(2)
 |      >>> b = np.ones((2, 2)) * 2
 |      >>> a.dot(b)
 |      array([[ 2.,  2.],
 |             [ 2.,  2.]])
 |      
 |      This array method can be conveniently chained:
 |      
 |      >>> a.dot(b).dot(b)
 |      array([[ 8.,  8.],
 |             [ 8.,  8.]])
 |  
 |  dump(...)
 |      a.dump(file)
 |      
 |      Dump a pickle of the array to the specified file.
 |      The array can be read back with pickle.load or numpy.load.
 |      
 |      Parameters
 |      ----------
 |      file : str
 |          A string naming the dump file.
 |  
 |  dumps(...)
 |      a.dumps()
 |      
 |      Returns the pickle of the array as a string.
 |      pickle.loads or numpy.loads will convert the string back to an array.
 |      
 |      Parameters
 |      ----------
 |      None
 |  
 |  fill(...)
 |      a.fill(value)
 |      
 |      Fill the array with a scalar value.
 |      
 |      Parameters
 |      ----------
 |      value : scalar
 |          All elements of `a` will be assigned this value.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([1, 2])
 |      >>> a.fill(0)
 |      >>> a
 |      array([0, 0])
 |      >>> a = np.empty(2)
 |      >>> a.fill(1)
 |      >>> a
 |      array([ 1.,  1.])
 |  
 |  flatten(...)
 |      a.flatten(order='C')
 |      
 |      Return a copy of the array collapsed into one dimension.
 |      
 |      Parameters
 |      ----------
 |      order : {'C', 'F', 'A'}, optional
 |          Whether to flatten in row-major (C-style) or
 |          column-major (Fortran-style) order or preserve the
 |          C/Fortran ordering from `a`.  The default is 'C'.
 |      
 |      Returns
 |      -------
 |      y : ndarray
 |          A copy of the input array, flattened to one dimension.
 |      
 |      See Also
 |      --------
 |      ravel : Return a flattened array.
 |      flat : A 1-D flat iterator over the array.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([[1,2], [3,4]])
 |      >>> a.flatten()
 |      array([1, 2, 3, 4])
 |      >>> a.flatten('F')
 |      array([1, 3, 2, 4])
 |  
 |  getfield(...)
 |      a.getfield(dtype, offset=0)
 |      
 |      Returns a field of the given array as a certain type.
 |      
 |      A field is a view of the array data with a given data-type. The values in
 |      the view are determined by the given type and the offset into the current
 |      array in bytes. The offset needs to be such that the view dtype fits in the
 |      array dtype; for example an array of dtype complex128 has 16-byte elements.
 |      If taking a view with a 32-bit integer (4 bytes), the offset needs to be
 |      between 0 and 12 bytes.
 |      
 |      Parameters
 |      ----------
 |      dtype : str or dtype
 |          The data type of the view. The dtype size of the view can not be larger
 |          than that of the array itself.
 |      offset : int
 |          Number of bytes to skip before beginning the element view.
 |      
 |      Examples
 |      --------
 |      >>> x = np.diag([1.+1.j]*2)
 |      >>> x[1, 1] = 2 + 4.j
 |      >>> x
 |      array([[ 1.+1.j,  0.+0.j],
 |             [ 0.+0.j,  2.+4.j]])
 |      >>> x.getfield(np.float64)
 |      array([[ 1.,  0.],
 |             [ 0.,  2.]])
 |      
 |      By choosing an offset of 8 bytes we can select the complex part of the
 |      array for our view:
 |      
 |      >>> x.getfield(np.float64, offset=8)
 |      array([[ 1.,  0.],
 |         [ 0.,  4.]])
 |  
 |  item(...)
 |      a.item(*args)
 |      
 |      Copy an element of an array to a standard Python scalar and return it.
 |      
 |      Parameters
 |      ----------
 |      \*args : Arguments (variable number and type)
 |      
 |          * none: in this case, the method only works for arrays
 |            with one element (`a.size == 1`), which element is
 |            copied into a standard Python scalar object and returned.
 |      
 |          * int_type: this argument is interpreted as a flat index into
 |            the array, specifying which element to copy and return.
 |      
 |          * tuple of int_types: functions as does a single int_type argument,
 |            except that the argument is interpreted as an nd-index into the
 |            array.
 |      
 |      Returns
 |      -------
 |      z : Standard Python scalar object
 |          A copy of the specified element of the array as a suitable
 |          Python scalar
 |      
 |      Notes
 |      -----
 |      When the data type of `a` is longdouble or clongdouble, item() returns
 |      a scalar array object because there is no available Python scalar that
 |      would not lose information. Void arrays return a buffer object for item(),
 |      unless fields are defined, in which case a tuple is returned.
 |      
 |      `item` is very similar to a[args], except, instead of an array scalar,
 |      a standard Python scalar is returned. This can be useful for speeding up
 |      access to elements of the array and doing arithmetic on elements of the
 |      array using Python's optimized math.
 |      
 |      Examples
 |      --------
 |      >>> x = np.random.randint(9, size=(3, 3))
 |      >>> x
 |      array([[3, 1, 7],
 |             [2, 8, 3],
 |             [8, 5, 3]])
 |      >>> x.item(3)
 |      2
 |      >>> x.item(7)
 |      5
 |      >>> x.item((0, 1))
 |      1
 |      >>> x.item((2, 2))
 |      3
 |  
 |  itemset(...)
 |      a.itemset(*args)
 |      
 |      Insert scalar into an array (scalar is cast to array's dtype, if possible)
 |      
 |      There must be at least 1 argument, and define the last argument
 |      as *item*.  Then, ``a.itemset(*args)`` is equivalent to but faster
 |      than ``a[args] = item``.  The item should be a scalar value and `args`
 |      must select a single item in the array `a`.
 |      
 |      Parameters
 |      ----------
 |      \*args : Arguments
 |          If one argument: a scalar, only used in case `a` is of size 1.
 |          If two arguments: the last argument is the value to be set
 |          and must be a scalar, the first argument specifies a single array
 |          element location. It is either an int or a tuple.
 |      
 |      Notes
 |      -----
 |      Compared to indexing syntax, `itemset` provides some speed increase
 |      for placing a scalar into a particular location in an `ndarray`,
 |      if you must do this.  However, generally this is discouraged:
 |      among other problems, it complicates the appearance of the code.
 |      Also, when using `itemset` (and `item`) inside a loop, be sure
 |      to assign the methods to a local variable to avoid the attribute
 |      look-up at each loop iteration.
 |      
 |      Examples
 |      --------
 |      >>> x = np.random.randint(9, size=(3, 3))
 |      >>> x
 |      array([[3, 1, 7],
 |             [2, 8, 3],
 |             [8, 5, 3]])
 |      >>> x.itemset(4, 0)
 |      >>> x.itemset((2, 2), 9)
 |      >>> x
 |      array([[3, 1, 7],
 |             [2, 0, 3],
 |             [8, 5, 9]])
 |  
 |  max(...)
 |      a.max(axis=None, out=None)
 |      
 |      Return the maximum along a given axis.
 |      
 |      Refer to `numpy.amax` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.amax : equivalent function
 |  
 |  mean(...)
 |      a.mean(axis=None, dtype=None, out=None, keepdims=False)
 |      
 |      Returns the average of the array elements along given axis.
 |      
 |      Refer to `numpy.mean` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.mean : equivalent function
 |  
 |  min(...)
 |      a.min(axis=None, out=None, keepdims=False)
 |      
 |      Return the minimum along a given axis.
 |      
 |      Refer to `numpy.amin` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.amin : equivalent function
 |  
 |  newbyteorder(...)
 |      arr.newbyteorder(new_order='S')
 |      
 |      Return the array with the same data viewed with a different byte order.
 |      
 |      Equivalent to::
 |      
 |          arr.view(arr.dtype.newbytorder(new_order))
 |      
 |      Changes are also made in all fields and sub-arrays of the array data
 |      type.
 |      
 |      
 |      
 |      Parameters
 |      ----------
 |      new_order : string, optional
 |          Byte order to force; a value from the byte order specifications
 |          above. `new_order` codes can be any of::
 |      
 |           * 'S' - swap dtype from current to opposite endian
 |           * {'<', 'L'} - little endian
 |           * {'>', 'B'} - big endian
 |           * {'=', 'N'} - native order
 |           * {'|', 'I'} - ignore (no change to byte order)
 |      
 |          The default value ('S') results in swapping the current
 |          byte order. The code does a case-insensitive check on the first
 |          letter of `new_order` for the alternatives above.  For example,
 |          any of 'B' or 'b' or 'biggish' are valid to specify big-endian.
 |      
 |      
 |      Returns
 |      -------
 |      new_arr : array
 |          New array object with the dtype reflecting given change to the
 |          byte order.
 |  
 |  nonzero(...)
 |      a.nonzero()
 |      
 |      Return the indices of the elements that are non-zero.
 |      
 |      Refer to `numpy.nonzero` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.nonzero : equivalent function
 |  
 |  partition(...)
 |      a.partition(kth, axis=-1, kind='introselect', order=None)
 |      
 |      Rearranges the elements in the array in such a way that value of the
 |      element in kth position is in the position it would be in a sorted array.
 |      All elements smaller than the kth element are moved before this element and
 |      all equal or greater are moved behind it. The ordering of the elements in
 |      the two partitions is undefined.
 |      
 |      .. versionadded:: 1.8.0
 |      
 |      Parameters
 |      ----------
 |      kth : int or sequence of ints
 |          Element index to partition by. The kth element value will be in its
 |          final sorted position and all smaller elements will be moved before it
 |          and all equal or greater elements behind it.
 |          The order all elements in the partitions is undefined.
 |          If provided with a sequence of kth it will partition all elements
 |          indexed by kth of them into their sorted position at once.
 |      axis : int, optional
 |          Axis along which to sort. Default is -1, which means sort along the
 |          last axis.
 |      kind : {'introselect'}, optional
 |          Selection algorithm. Default is 'introselect'.
 |      order : str or list of str, optional
 |          When `a` is an array with fields defined, this argument specifies
 |          which fields to compare first, second, etc.  A single field can
 |          be specified as a string, and not all fields need be specified,
 |          but unspecified fields will still be used, in the order in which
 |          they come up in the dtype, to break ties.
 |      
 |      See Also
 |      --------
 |      numpy.partition : Return a parititioned copy of an array.
 |      argpartition : Indirect partition.
 |      sort : Full sort.
 |      
 |      Notes
 |      -----
 |      See ``np.partition`` for notes on the different algorithms.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([3, 4, 2, 1])
 |      >>> a.partition(a, 3)
 |      >>> a
 |      array([2, 1, 3, 4])
 |      
 |      >>> a.partition((1, 3))
 |      array([1, 2, 3, 4])
 |  
 |  prod(...)
 |      a.prod(axis=None, dtype=None, out=None, keepdims=False)
 |      
 |      Return the product of the array elements over the given axis
 |      
 |      Refer to `numpy.prod` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.prod : equivalent function
 |  
 |  ptp(...)
 |      a.ptp(axis=None, out=None)
 |      
 |      Peak to peak (maximum - minimum) value along a given axis.
 |      
 |      Refer to `numpy.ptp` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.ptp : equivalent function
 |  
 |  put(...)
 |      a.put(indices, values, mode='raise')
 |      
 |      Set ``a.flat[n] = values[n]`` for all `n` in indices.
 |      
 |      Refer to `numpy.put` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.put : equivalent function
 |  
 |  ravel(...)
 |      a.ravel([order])
 |      
 |      Return a flattened array.
 |      
 |      Refer to `numpy.ravel` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.ravel : equivalent function
 |      
 |      ndarray.flat : a flat iterator on the array.
 |  
 |  repeat(...)
 |      a.repeat(repeats, axis=None)
 |      
 |      Repeat elements of an array.
 |      
 |      Refer to `numpy.repeat` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.repeat : equivalent function
 |  
 |  reshape(...)
 |      a.reshape(shape, order='C')
 |      
 |      Returns an array containing the same data with a new shape.
 |      
 |      Refer to `numpy.reshape` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.reshape : equivalent function
 |  
 |  resize(...)
 |      a.resize(new_shape, refcheck=True)
 |      
 |      Change shape and size of array in-place.
 |      
 |      Parameters
 |      ----------
 |      new_shape : tuple of ints, or `n` ints
 |          Shape of resized array.
 |      refcheck : bool, optional
 |          If False, reference count will not be checked. Default is True.
 |      
 |      Returns
 |      -------
 |      None
 |      
 |      Raises
 |      ------
 |      ValueError
 |          If `a` does not own its own data or references or views to it exist,
 |          and the data memory must be changed.
 |      
 |      SystemError
 |          If the `order` keyword argument is specified. This behaviour is a
 |          bug in NumPy.
 |      
 |      See Also
 |      --------
 |      resize : Return a new array with the specified shape.
 |      
 |      Notes
 |      -----
 |      This reallocates space for the data area if necessary.
 |      
 |      Only contiguous arrays (data elements consecutive in memory) can be
 |      resized.
 |      
 |      The purpose of the reference count check is to make sure you
 |      do not use this array as a buffer for another Python object and then
 |      reallocate the memory. However, reference counts can increase in
 |      other ways so if you are sure that you have not shared the memory
 |      for this array with another Python object, then you may safely set
 |      `refcheck` to False.
 |      
 |      Examples
 |      --------
 |      Shrinking an array: array is flattened (in the order that the data are
 |      stored in memory), resized, and reshaped:
 |      
 |      >>> a = np.array([[0, 1], [2, 3]], order='C')
 |      >>> a.resize((2, 1))
 |      >>> a
 |      array([[0],
 |             [1]])
 |      
 |      >>> a = np.array([[0, 1], [2, 3]], order='F')
 |      >>> a.resize((2, 1))
 |      >>> a
 |      array([[0],
 |             [2]])
 |      
 |      Enlarging an array: as above, but missing entries are filled with zeros:
 |      
 |      >>> b = np.array([[0, 1], [2, 3]])
 |      >>> b.resize(2, 3) # new_shape parameter doesn't have to be a tuple
 |      >>> b
 |      array([[0, 1, 2],
 |             [3, 0, 0]])
 |      
 |      Referencing an array prevents resizing...
 |      
 |      >>> c = a
 |      >>> a.resize((1, 1))
 |      Traceback (most recent call last):
 |      ...
 |      ValueError: cannot resize an array that has been referenced ...
 |      
 |      Unless `refcheck` is False:
 |      
 |      >>> a.resize((1, 1), refcheck=False)
 |      >>> a
 |      array([[0]])
 |      >>> c
 |      array([[0]])
 |  
 |  round(...)
 |      a.round(decimals=0, out=None)
 |      
 |      Return `a` with each element rounded to the given number of decimals.
 |      
 |      Refer to `numpy.around` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.around : equivalent function
 |  
 |  searchsorted(...)
 |      a.searchsorted(v, side='left', sorter=None)
 |      
 |      Find indices where elements of v should be inserted in a to maintain order.
 |      
 |      For full documentation, see `numpy.searchsorted`
 |      
 |      See Also
 |      --------
 |      numpy.searchsorted : equivalent function
 |  
 |  setfield(...)
 |      a.setfield(val, dtype, offset=0)
 |      
 |      Put a value into a specified place in a field defined by a data-type.
 |      
 |      Place `val` into `a`'s field defined by `dtype` and beginning `offset`
 |      bytes into the field.
 |      
 |      Parameters
 |      ----------
 |      val : object
 |          Value to be placed in field.
 |      dtype : dtype object
 |          Data-type of the field in which to place `val`.
 |      offset : int, optional
 |          The number of bytes into the field at which to place `val`.
 |      
 |      Returns
 |      -------
 |      None
 |      
 |      See Also
 |      --------
 |      getfield
 |      
 |      Examples
 |      --------
 |      >>> x = np.eye(3)
 |      >>> x.getfield(np.float64)
 |      array([[ 1.,  0.,  0.],
 |             [ 0.,  1.,  0.],
 |             [ 0.,  0.,  1.]])
 |      >>> x.setfield(3, np.int32)
 |      >>> x.getfield(np.int32)
 |      array([[3, 3, 3],
 |             [3, 3, 3],
 |             [3, 3, 3]])
 |      >>> x
 |      array([[  1.00000000e+000,   1.48219694e-323,   1.48219694e-323],
 |             [  1.48219694e-323,   1.00000000e+000,   1.48219694e-323],
 |             [  1.48219694e-323,   1.48219694e-323,   1.00000000e+000]])
 |      >>> x.setfield(np.eye(3), np.int32)
 |      >>> x
 |      array([[ 1.,  0.,  0.],
 |             [ 0.,  1.,  0.],
 |             [ 0.,  0.,  1.]])
 |  
 |  setflags(...)
 |      a.setflags(write=None, align=None, uic=None)
 |      
 |      Set array flags WRITEABLE, ALIGNED, and UPDATEIFCOPY, respectively.
 |      
 |      These Boolean-valued flags affect how numpy interprets the memory
 |      area used by `a` (see Notes below). The ALIGNED flag can only
 |      be set to True if the data is actually aligned according to the type.
 |      The UPDATEIFCOPY flag can never be set to True. The flag WRITEABLE
 |      can only be set to True if the array owns its own memory, or the
 |      ultimate owner of the memory exposes a writeable buffer interface,
 |      or is a string. (The exception for string is made so that unpickling
 |      can be done without copying memory.)
 |      
 |      Parameters
 |      ----------
 |      write : bool, optional
 |          Describes whether or not `a` can be written to.
 |      align : bool, optional
 |          Describes whether or not `a` is aligned properly for its type.
 |      uic : bool, optional
 |          Describes whether or not `a` is a copy of another "base" array.
 |      
 |      Notes
 |      -----
 |      Array flags provide information about how the memory area used
 |      for the array is to be interpreted. There are 6 Boolean flags
 |      in use, only three of which can be changed by the user:
 |      UPDATEIFCOPY, WRITEABLE, and ALIGNED.
 |      
 |      WRITEABLE (W) the data area can be written to;
 |      
 |      ALIGNED (A) the data and strides are aligned appropriately for the hardware
 |      (as determined by the compiler);
 |      
 |      UPDATEIFCOPY (U) this array is a copy of some other array (referenced
 |      by .base). When this array is deallocated, the base array will be
 |      updated with the contents of this array.
 |      
 |      All flags can be accessed using their first (upper case) letter as well
 |      as the full name.
 |      
 |      Examples
 |      --------
 |      >>> y
 |      array([[3, 1, 7],
 |             [2, 0, 0],
 |             [8, 5, 9]])
 |      >>> y.flags
 |        C_CONTIGUOUS : True
 |        F_CONTIGUOUS : False
 |        OWNDATA : True
 |        WRITEABLE : True
 |        ALIGNED : True
 |        UPDATEIFCOPY : False
 |      >>> y.setflags(write=0, align=0)
 |      >>> y.flags
 |        C_CONTIGUOUS : True
 |        F_CONTIGUOUS : False
 |        OWNDATA : True
 |        WRITEABLE : False
 |        ALIGNED : False
 |        UPDATEIFCOPY : False
 |      >>> y.setflags(uic=1)
 |      Traceback (most recent call last):
 |        File "<stdin>", line 1, in <module>
 |      ValueError: cannot set UPDATEIFCOPY flag to True
 |  
 |  sort(...)
 |      a.sort(axis=-1, kind='quicksort', order=None)
 |      
 |      Sort an array, in-place.
 |      
 |      Parameters
 |      ----------
 |      axis : int, optional
 |          Axis along which to sort. Default is -1, which means sort along the
 |          last axis.
 |      kind : {'quicksort', 'mergesort', 'heapsort'}, optional
 |          Sorting algorithm. Default is 'quicksort'.
 |      order : str or list of str, optional
 |          When `a` is an array with fields defined, this argument specifies
 |          which fields to compare first, second, etc.  A single field can
 |          be specified as a string, and not all fields need be specified,
 |          but unspecified fields will still be used, in the order in which
 |          they come up in the dtype, to break ties.
 |      
 |      See Also
 |      --------
 |      numpy.sort : Return a sorted copy of an array.
 |      argsort : Indirect sort.
 |      lexsort : Indirect stable sort on multiple keys.
 |      searchsorted : Find elements in sorted array.
 |      partition: Partial sort.
 |      
 |      Notes
 |      -----
 |      See ``sort`` for notes on the different sorting algorithms.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([[1,4], [3,1]])
 |      >>> a.sort(axis=1)
 |      >>> a
 |      array([[1, 4],
 |             [1, 3]])
 |      >>> a.sort(axis=0)
 |      >>> a
 |      array([[1, 3],
 |             [1, 4]])
 |      
 |      Use the `order` keyword to specify a field to use when sorting a
 |      structured array:
 |      
 |      >>> a = np.array([('a', 2), ('c', 1)], dtype=[('x', 'S1'), ('y', int)])
 |      >>> a.sort(order='y')
 |      >>> a
 |      array([('c', 1), ('a', 2)],
 |            dtype=[('x', '|S1'), ('y', '<i4')])
 |  
 |  squeeze(...)
 |      a.squeeze(axis=None)
 |      
 |      Remove single-dimensional entries from the shape of `a`.
 |      
 |      Refer to `numpy.squeeze` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.squeeze : equivalent function
 |  
 |  std(...)
 |      a.std(axis=None, dtype=None, out=None, ddof=0, keepdims=False)
 |      
 |      Returns the standard deviation of the array elements along given axis.
 |      
 |      Refer to `numpy.std` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.std : equivalent function
 |  
 |  sum(...)
 |      a.sum(axis=None, dtype=None, out=None, keepdims=False)
 |      
 |      Return the sum of the array elements over the given axis.
 |      
 |      Refer to `numpy.sum` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.sum : equivalent function
 |  
 |  swapaxes(...)
 |      a.swapaxes(axis1, axis2)
 |      
 |      Return a view of the array with `axis1` and `axis2` interchanged.
 |      
 |      Refer to `numpy.swapaxes` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.swapaxes : equivalent function
 |  
 |  take(...)
 |      a.take(indices, axis=None, out=None, mode='raise')
 |      
 |      Return an array formed from the elements of `a` at the given indices.
 |      
 |      Refer to `numpy.take` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.take : equivalent function
 |  
 |  tobytes(...)
 |      a.tobytes(order='C')
 |      
 |      Construct Python bytes containing the raw data bytes in the array.
 |      
 |      Constructs Python bytes showing a copy of the raw contents of
 |      data memory. The bytes object can be produced in either 'C' or 'Fortran',
 |      or 'Any' order (the default is 'C'-order). 'Any' order means C-order
 |      unless the F_CONTIGUOUS flag in the array is set, in which case it
 |      means 'Fortran' order.
 |      
 |      .. versionadded:: 1.9.0
 |      
 |      Parameters
 |      ----------
 |      order : {'C', 'F', None}, optional
 |          Order of the data for multidimensional arrays:
 |          C, Fortran, or the same as for the original array.
 |      
 |      Returns
 |      -------
 |      s : bytes
 |          Python bytes exhibiting a copy of `a`'s raw data.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([[0, 1], [2, 3]])
 |      >>> x.tobytes()
 |      b'\x00\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x03\x00\x00\x00'
 |      >>> x.tobytes('C') == x.tobytes()
 |      True
 |      >>> x.tobytes('F')
 |      b'\x00\x00\x00\x00\x02\x00\x00\x00\x01\x00\x00\x00\x03\x00\x00\x00'
 |  
 |  tofile(...)
 |      a.tofile(fid, sep="", format="%s")
 |      
 |      Write array to a file as text or binary (default).
 |      
 |      Data is always written in 'C' order, independent of the order of `a`.
 |      The data produced by this method can be recovered using the function
 |      fromfile().
 |      
 |      Parameters
 |      ----------
 |      fid : file or str
 |          An open file object, or a string containing a filename.
 |      sep : str
 |          Separator between array items for text output.
 |          If "" (empty), a binary file is written, equivalent to
 |          ``file.write(a.tobytes())``.
 |      format : str
 |          Format string for text file output.
 |          Each entry in the array is formatted to text by first converting
 |          it to the closest Python type, and then using "format" % item.
 |      
 |      Notes
 |      -----
 |      This is a convenience function for quick storage of array data.
 |      Information on endianness and precision is lost, so this method is not a
 |      good choice for files intended to archive data or transport data between
 |      machines with different endianness. Some of these problems can be overcome
 |      by outputting the data as text files, at the expense of speed and file
 |      size.
 |  
 |  tolist(...)
 |      a.tolist()
 |      
 |      Return the array as a (possibly nested) list.
 |      
 |      Return a copy of the array data as a (nested) Python list.
 |      Data items are converted to the nearest compatible Python type.
 |      
 |      Parameters
 |      ----------
 |      none
 |      
 |      Returns
 |      -------
 |      y : list
 |          The possibly nested list of array elements.
 |      
 |      Notes
 |      -----
 |      The array may be recreated, ``a = np.array(a.tolist())``.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([1, 2])
 |      >>> a.tolist()
 |      [1, 2]
 |      >>> a = np.array([[1, 2], [3, 4]])
 |      >>> list(a)
 |      [array([1, 2]), array([3, 4])]
 |      >>> a.tolist()
 |      [[1, 2], [3, 4]]
 |  
 |  tostring(...)
 |      a.tostring(order='C')
 |      
 |      Construct Python bytes containing the raw data bytes in the array.
 |      
 |      Constructs Python bytes showing a copy of the raw contents of
 |      data memory. The bytes object can be produced in either 'C' or 'Fortran',
 |      or 'Any' order (the default is 'C'-order). 'Any' order means C-order
 |      unless the F_CONTIGUOUS flag in the array is set, in which case it
 |      means 'Fortran' order.
 |      
 |      This function is a compatibility alias for tobytes. Despite its name it returns bytes not strings.
 |      
 |      Parameters
 |      ----------
 |      order : {'C', 'F', None}, optional
 |          Order of the data for multidimensional arrays:
 |          C, Fortran, or the same as for the original array.
 |      
 |      Returns
 |      -------
 |      s : bytes
 |          Python bytes exhibiting a copy of `a`'s raw data.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([[0, 1], [2, 3]])
 |      >>> x.tobytes()
 |      b'\x00\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x03\x00\x00\x00'
 |      >>> x.tobytes('C') == x.tobytes()
 |      True
 |      >>> x.tobytes('F')
 |      b'\x00\x00\x00\x00\x02\x00\x00\x00\x01\x00\x00\x00\x03\x00\x00\x00'
 |  
 |  trace(...)
 |      a.trace(offset=0, axis1=0, axis2=1, dtype=None, out=None)
 |      
 |      Return the sum along diagonals of the array.
 |      
 |      Refer to `numpy.trace` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.trace : equivalent function
 |  
 |  transpose(...)
 |      a.transpose(*axes)
 |      
 |      Returns a view of the array with axes transposed.
 |      
 |      For a 1-D array, this has no effect. (To change between column and
 |      row vectors, first cast the 1-D array into a matrix object.)
 |      For a 2-D array, this is the usual matrix transpose.
 |      For an n-D array, if axes are given, their order indicates how the
 |      axes are permuted (see Examples). If axes are not provided and
 |      ``a.shape = (i[0], i[1], ... i[n-2], i[n-1])``, then
 |      ``a.transpose().shape = (i[n-1], i[n-2], ... i[1], i[0])``.
 |      
 |      Parameters
 |      ----------
 |      axes : None, tuple of ints, or `n` ints
 |      
 |       * None or no argument: reverses the order of the axes.
 |      
 |       * tuple of ints: `i` in the `j`-th place in the tuple means `a`'s
 |         `i`-th axis becomes `a.transpose()`'s `j`-th axis.
 |      
 |       * `n` ints: same as an n-tuple of the same ints (this form is
 |         intended simply as a "convenience" alternative to the tuple form)
 |      
 |      Returns
 |      -------
 |      out : ndarray
 |          View of `a`, with axes suitably permuted.
 |      
 |      See Also
 |      --------
 |      ndarray.T : Array property returning the array transposed.
 |      
 |      Examples
 |      --------
 |      >>> a = np.array([[1, 2], [3, 4]])
 |      >>> a
 |      array([[1, 2],
 |             [3, 4]])
 |      >>> a.transpose()
 |      array([[1, 3],
 |             [2, 4]])
 |      >>> a.transpose((1, 0))
 |      array([[1, 3],
 |             [2, 4]])
 |      >>> a.transpose(1, 0)
 |      array([[1, 3],
 |             [2, 4]])
 |  
 |  var(...)
 |      a.var(axis=None, dtype=None, out=None, ddof=0, keepdims=False)
 |      
 |      Returns the variance of the array elements, along given axis.
 |      
 |      Refer to `numpy.var` for full documentation.
 |      
 |      See Also
 |      --------
 |      numpy.var : equivalent function
 |  
 |  view(...)
 |      a.view(dtype=None, type=None)
 |      
 |      New view of array with the same data.
 |      
 |      Parameters
 |      ----------
 |      dtype : data-type or ndarray sub-class, optional
 |          Data-type descriptor of the returned view, e.g., float32 or int16. The
 |          default, None, results in the view having the same data-type as `a`.
 |          This argument can also be specified as an ndarray sub-class, which
 |          then specifies the type of the returned object (this is equivalent to
 |          setting the ``type`` parameter).
 |      type : Python type, optional
 |          Type of the returned view, e.g., ndarray or matrix.  Again, the
 |          default None results in type preservation.
 |      
 |      Notes
 |      -----
 |      ``a.view()`` is used two different ways:
 |      
 |      ``a.view(some_dtype)`` or ``a.view(dtype=some_dtype)`` constructs a view
 |      of the array's memory with a different data-type.  This can cause a
 |      reinterpretation of the bytes of memory.
 |      
 |      ``a.view(ndarray_subclass)`` or ``a.view(type=ndarray_subclass)`` just
 |      returns an instance of `ndarray_subclass` that looks at the same array
 |      (same shape, dtype, etc.)  This does not cause a reinterpretation of the
 |      memory.
 |      
 |      For ``a.view(some_dtype)``, if ``some_dtype`` has a different number of
 |      bytes per entry than the previous dtype (for example, converting a
 |      regular array to a structured array), then the behavior of the view
 |      cannot be predicted just from the superficial appearance of ``a`` (shown
 |      by ``print(a)``). It also depends on exactly how ``a`` is stored in
 |      memory. Therefore if ``a`` is C-ordered versus fortran-ordered, versus
 |      defined as a slice or transpose, etc., the view may give different
 |      results.
 |      
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([(1, 2)], dtype=[('a', np.int8), ('b', np.int8)])
 |      
 |      Viewing array data using a different type and dtype:
 |      
 |      >>> y = x.view(dtype=np.int16, type=np.matrix)
 |      >>> y
 |      matrix([[513]], dtype=int16)
 |      >>> print type(y)
 |      <class 'numpy.matrixlib.defmatrix.matrix'>
 |      
 |      Creating a view on a structured array so it can be used in calculations
 |      
 |      >>> x = np.array([(1, 2),(3,4)], dtype=[('a', np.int8), ('b', np.int8)])
 |      >>> xv = x.view(dtype=np.int8).reshape(-1,2)
 |      >>> xv
 |      array([[1, 2],
 |             [3, 4]], dtype=int8)
 |      >>> xv.mean(0)
 |      array([ 2.,  3.])
 |      
 |      Making changes to the view changes the underlying array
 |      
 |      >>> xv[0,1] = 20
 |      >>> print x
 |      [(1, 20) (3, 4)]
 |      
 |      Using a view to convert an array to a recarray:
 |      
 |      >>> z = x.view(np.recarray)
 |      >>> z.a
 |      array([1], dtype=int8)
 |      
 |      Views share data:
 |      
 |      >>> x[0] = (9, 10)
 |      >>> z[0]
 |      (9, 10)
 |      
 |      Views that change the dtype size (bytes per entry) should normally be
 |      avoided on arrays defined by slices, transposes, fortran-ordering, etc.:
 |      
 |      >>> x = np.array([[1,2,3],[4,5,6]], dtype=np.int16)
 |      >>> y = x[:, 0:2]
 |      >>> y
 |      array([[1, 2],
 |             [4, 5]], dtype=int16)
 |      >>> y.view(dtype=[('width', np.int16), ('length', np.int16)])
 |      Traceback (most recent call last):
 |        File "<stdin>", line 1, in <module>
 |      ValueError: new type not compatible with array.
 |      >>> z = y.copy()
 |      >>> z.view(dtype=[('width', np.int16), ('length', np.int16)])
 |      array([[(1, 2)],
 |             [(4, 5)]], dtype=[('width', '<i2'), ('length', '<i2')])
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |  
 |  T
 |      Same as self.transpose(), except that self is returned if
 |      self.ndim < 2.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([[1.,2.],[3.,4.]])
 |      >>> x
 |      array([[ 1.,  2.],
 |             [ 3.,  4.]])
 |      >>> x.T
 |      array([[ 1.,  3.],
 |             [ 2.,  4.]])
 |      >>> x = np.array([1.,2.,3.,4.])
 |      >>> x
 |      array([ 1.,  2.,  3.,  4.])
 |      >>> x.T
 |      array([ 1.,  2.,  3.,  4.])
 |  
 |  __array_finalize__
 |      None.
 |  
 |  __array_interface__
 |      Array protocol: Python side.
 |  
 |  __array_priority__
 |      Array priority.
 |  
 |  __array_struct__
 |      Array protocol: C-struct side.
 |  
 |  base
 |      Base object if memory is from some other object.
 |      
 |      Examples
 |      --------
 |      The base of an array that owns its memory is None:
 |      
 |      >>> x = np.array([1,2,3,4])
 |      >>> x.base is None
 |      True
 |      
 |      Slicing creates a view, whose memory is shared with x:
 |      
 |      >>> y = x[2:]
 |      >>> y.base is x
 |      True
 |  
 |  ctypes
 |      An object to simplify the interaction of the array with the ctypes
 |      module.
 |      
 |      This attribute creates an object that makes it easier to use arrays
 |      when calling shared libraries with the ctypes module. The returned
 |      object has, among others, data, shape, and strides attributes (see
 |      Notes below) which themselves return ctypes objects that can be used
 |      as arguments to a shared library.
 |      
 |      Parameters
 |      ----------
 |      None
 |      
 |      Returns
 |      -------
 |      c : Python object
 |          Possessing attributes data, shape, strides, etc.
 |      
 |      See Also
 |      --------
 |      numpy.ctypeslib
 |      
 |      Notes
 |      -----
 |      Below are the public attributes of this object which were documented
 |      in "Guide to NumPy" (we have omitted undocumented public attributes,
 |      as well as documented private attributes):
 |      
 |      * data: A pointer to the memory area of the array as a Python integer.
 |        This memory area may contain data that is not aligned, or not in correct
 |        byte-order. The memory area may not even be writeable. The array
 |        flags and data-type of this array should be respected when passing this
 |        attribute to arbitrary C-code to avoid trouble that can include Python
 |        crashing. User Beware! The value of this attribute is exactly the same
 |        as self._array_interface_['data'][0].
 |      
 |      * shape (c_intp*self.ndim): A ctypes array of length self.ndim where
 |        the basetype is the C-integer corresponding to dtype('p') on this
 |        platform. This base-type could be c_int, c_long, or c_longlong
 |        depending on the platform. The c_intp type is defined accordingly in
 |        numpy.ctypeslib. The ctypes array contains the shape of the underlying
 |        array.
 |      
 |      * strides (c_intp*self.ndim): A ctypes array of length self.ndim where
 |        the basetype is the same as for the shape attribute. This ctypes array
 |        contains the strides information from the underlying array. This strides
 |        information is important for showing how many bytes must be jumped to
 |        get to the next element in the array.
 |      
 |      * data_as(obj): Return the data pointer cast to a particular c-types object.
 |        For example, calling self._as_parameter_ is equivalent to
 |        self.data_as(ctypes.c_void_p). Perhaps you want to use the data as a
 |        pointer to a ctypes array of floating-point data:
 |        self.data_as(ctypes.POINTER(ctypes.c_double)).
 |      
 |      * shape_as(obj): Return the shape tuple as an array of some other c-types
 |        type. For example: self.shape_as(ctypes.c_short).
 |      
 |      * strides_as(obj): Return the strides tuple as an array of some other
 |        c-types type. For example: self.strides_as(ctypes.c_longlong).
 |      
 |      Be careful using the ctypes attribute - especially on temporary
 |      arrays or arrays constructed on the fly. For example, calling
 |      ``(a+b).ctypes.data_as(ctypes.c_void_p)`` returns a pointer to memory
 |      that is invalid because the array created as (a+b) is deallocated
 |      before the next Python statement. You can avoid this problem using
 |      either ``c=a+b`` or ``ct=(a+b).ctypes``. In the latter case, ct will
 |      hold a reference to the array until ct is deleted or re-assigned.
 |      
 |      If the ctypes module is not available, then the ctypes attribute
 |      of array objects still returns something useful, but ctypes objects
 |      are not returned and errors may be raised instead. In particular,
 |      the object will still have the as parameter attribute which will
 |      return an integer equal to the data attribute.
 |      
 |      Examples
 |      --------
 |      >>> import ctypes
 |      >>> x
 |      array([[0, 1],
 |             [2, 3]])
 |      >>> x.ctypes.data
 |      30439712
 |      >>> x.ctypes.data_as(ctypes.POINTER(ctypes.c_long))
 |      <ctypes.LP_c_long object at 0x01F01300>
 |      >>> x.ctypes.data_as(ctypes.POINTER(ctypes.c_long)).contents
 |      c_long(0)
 |      >>> x.ctypes.data_as(ctypes.POINTER(ctypes.c_longlong)).contents
 |      c_longlong(4294967296L)
 |      >>> x.ctypes.shape
 |      <numpy.core._internal.c_long_Array_2 object at 0x01FFD580>
 |      >>> x.ctypes.shape_as(ctypes.c_long)
 |      <numpy.core._internal.c_long_Array_2 object at 0x01FCE620>
 |      >>> x.ctypes.strides
 |      <numpy.core._internal.c_long_Array_2 object at 0x01FCE620>
 |      >>> x.ctypes.strides_as(ctypes.c_longlong)
 |      <numpy.core._internal.c_longlong_Array_2 object at 0x01F01300>
 |  
 |  data
 |      Python buffer object pointing to the start of the array's data.
 |  
 |  dtype
 |      Data-type of the array's elements.
 |      
 |      Parameters
 |      ----------
 |      None
 |      
 |      Returns
 |      -------
 |      d : numpy dtype object
 |      
 |      See Also
 |      --------
 |      numpy.dtype
 |      
 |      Examples
 |      --------
 |      >>> x
 |      array([[0, 1],
 |             [2, 3]])
 |      >>> x.dtype
 |      dtype('int32')
 |      >>> type(x.dtype)
 |      <type 'numpy.dtype'>
 |  
 |  flags
 |      Information about the memory layout of the array.
 |      
 |      Attributes
 |      ----------
 |      C_CONTIGUOUS (C)
 |          The data is in a single, C-style contiguous segment.
 |      F_CONTIGUOUS (F)
 |          The data is in a single, Fortran-style contiguous segment.
 |      OWNDATA (O)
 |          The array owns the memory it uses or borrows it from another object.
 |      WRITEABLE (W)
 |          The data area can be written to.  Setting this to False locks
 |          the data, making it read-only.  A view (slice, etc.) inherits WRITEABLE
 |          from its base array at creation time, but a view of a writeable
 |          array may be subsequently locked while the base array remains writeable.
 |          (The opposite is not true, in that a view of a locked array may not
 |          be made writeable.  However, currently, locking a base object does not
 |          lock any views that already reference it, so under that circumstance it
 |          is possible to alter the contents of a locked array via a previously
 |          created writeable view onto it.)  Attempting to change a non-writeable
 |          array raises a RuntimeError exception.
 |      ALIGNED (A)
 |          The data and all elements are aligned appropriately for the hardware.
 |      UPDATEIFCOPY (U)
 |          This array is a copy of some other array. When this array is
 |          deallocated, the base array will be updated with the contents of
 |          this array.
 |      FNC
 |          F_CONTIGUOUS and not C_CONTIGUOUS.
 |      FORC
 |          F_CONTIGUOUS or C_CONTIGUOUS (one-segment test).
 |      BEHAVED (B)
 |          ALIGNED and WRITEABLE.
 |      CARRAY (CA)
 |          BEHAVED and C_CONTIGUOUS.
 |      FARRAY (FA)
 |          BEHAVED and F_CONTIGUOUS and not C_CONTIGUOUS.
 |      
 |      Notes
 |      -----
 |      The `flags` object can be accessed dictionary-like (as in ``a.flags['WRITEABLE']``),
 |      or by using lowercased attribute names (as in ``a.flags.writeable``). Short flag
 |      names are only supported in dictionary access.
 |      
 |      Only the UPDATEIFCOPY, WRITEABLE, and ALIGNED flags can be changed by
 |      the user, via direct assignment to the attribute or dictionary entry,
 |      or by calling `ndarray.setflags`.
 |      
 |      The array flags cannot be set arbitrarily:
 |      
 |      - UPDATEIFCOPY can only be set ``False``.
 |      - ALIGNED can only be set ``True`` if the data is truly aligned.
 |      - WRITEABLE can only be set ``True`` if the array owns its own memory
 |        or the ultimate owner of the memory exposes a writeable buffer
 |        interface or is a string.
 |      
 |      Arrays can be both C-style and Fortran-style contiguous simultaneously.
 |      This is clear for 1-dimensional arrays, but can also be true for higher
 |      dimensional arrays.
 |      
 |      Even for contiguous arrays a stride for a given dimension
 |      ``arr.strides[dim]`` may be *arbitrary* if ``arr.shape[dim] == 1``
 |      or the array has no elements.
 |      It does *not* generally hold that ``self.strides[-1] == self.itemsize``
 |      for C-style contiguous arrays or ``self.strides[0] == self.itemsize`` for
 |      Fortran-style contiguous arrays is true.
 |  
 |  flat
 |      A 1-D iterator over the array.
 |      
 |      This is a `numpy.flatiter` instance, which acts similarly to, but is not
 |      a subclass of, Python's built-in iterator object.
 |      
 |      See Also
 |      --------
 |      flatten : Return a copy of the array collapsed into one dimension.
 |      
 |      flatiter
 |      
 |      Examples
 |      --------
 |      >>> x = np.arange(1, 7).reshape(2, 3)
 |      >>> x
 |      array([[1, 2, 3],
 |             [4, 5, 6]])
 |      >>> x.flat[3]
 |      4
 |      >>> x.T
 |      array([[1, 4],
 |             [2, 5],
 |             [3, 6]])
 |      >>> x.T.flat[3]
 |      5
 |      >>> type(x.flat)
 |      <type 'numpy.flatiter'>
 |      
 |      An assignment example:
 |      
 |      >>> x.flat = 3; x
 |      array([[3, 3, 3],
 |             [3, 3, 3]])
 |      >>> x.flat[[1,4]] = 1; x
 |      array([[3, 1, 3],
 |             [3, 1, 3]])
 |  
 |  imag
 |      The imaginary part of the array.
 |      
 |      Examples
 |      --------
 |      >>> x = np.sqrt([1+0j, 0+1j])
 |      >>> x.imag
 |      array([ 0.        ,  0.70710678])
 |      >>> x.imag.dtype
 |      dtype('float64')
 |  
 |  itemsize
 |      Length of one array element in bytes.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([1,2,3], dtype=np.float64)
 |      >>> x.itemsize
 |      8
 |      >>> x = np.array([1,2,3], dtype=np.complex128)
 |      >>> x.itemsize
 |      16
 |  
 |  nbytes
 |      Total bytes consumed by the elements of the array.
 |      
 |      Notes
 |      -----
 |      Does not include memory consumed by non-element attributes of the
 |      array object.
 |      
 |      Examples
 |      --------
 |      >>> x = np.zeros((3,5,2), dtype=np.complex128)
 |      >>> x.nbytes
 |      480
 |      >>> np.prod(x.shape) * x.itemsize
 |      480
 |  
 |  ndim
 |      Number of array dimensions.
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([1, 2, 3])
 |      >>> x.ndim
 |      1
 |      >>> y = np.zeros((2, 3, 4))
 |      >>> y.ndim
 |      3
 |  
 |  real
 |      The real part of the array.
 |      
 |      Examples
 |      --------
 |      >>> x = np.sqrt([1+0j, 0+1j])
 |      >>> x.real
 |      array([ 1.        ,  0.70710678])
 |      >>> x.real.dtype
 |      dtype('float64')
 |      
 |      See Also
 |      --------
 |      numpy.real : equivalent function
 |  
 |  shape
 |      Tuple of array dimensions.
 |      
 |      Notes
 |      -----
 |      May be used to "reshape" the array, as long as this would not
 |      require a change in the total number of elements
 |      
 |      Examples
 |      --------
 |      >>> x = np.array([1, 2, 3, 4])
 |      >>> x.shape
 |      (4,)
 |      >>> y = np.zeros((2, 3, 4))
 |      >>> y.shape
 |      (2, 3, 4)
 |      >>> y.shape = (3, 8)
 |      >>> y
 |      array([[ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.],
 |             [ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.],
 |             [ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.]])
 |      >>> y.shape = (3, 6)
 |      Traceback (most recent call last):
 |        File "<stdin>", line 1, in <module>
 |      ValueError: total size of new array must be unchanged
 |  
 |  size
 |      Number of elements in the array.
 |      
 |      Equivalent to ``np.prod(a.shape)``, i.e., the product of the array's
 |      dimensions.
 |      
 |      Examples
 |      --------
 |      >>> x = np.zeros((3, 5, 2), dtype=np.complex128)
 |      >>> x.size
 |      30
 |      >>> np.prod(x.shape)
 |      30
 |  
 |  strides
 |      Tuple of bytes to step in each dimension when traversing an array.
 |      
 |      The byte offset of element ``(i[0], i[1], ..., i[n])`` in an array `a`
 |      is::
 |      
 |          offset = sum(np.array(i) * a.strides)
 |      
 |      A more detailed explanation of strides can be found in the
 |      "ndarray.rst" file in the NumPy reference guide.
 |      
 |      Notes
 |      -----
 |      Imagine an array of 32-bit integers (each 4 bytes)::
 |      
 |        x = np.array([[0, 1, 2, 3, 4],
 |                      [5, 6, 7, 8, 9]], dtype=np.int32)
 |      
 |      This array is stored in memory as 40 bytes, one after the other
 |      (known as a contiguous block of memory).  The strides of an array tell
 |      us how many bytes we have to skip in memory to move to the next position
 |      along a certain axis.  For example, we have to skip 4 bytes (1 value) to
 |      move to the next column, but 20 bytes (5 values) to get to the same
 |      position in the next row.  As such, the strides for the array `x` will be
 |      ``(20, 4)``.
 |      
 |      See Also
 |      --------
 |      numpy.lib.stride_tricks.as_strided
 |      
 |      Examples
 |      --------
 |      >>> y = np.reshape(np.arange(2*3*4), (2,3,4))
 |      >>> y
 |      array([[[ 0,  1,  2,  3],
 |              [ 4,  5,  6,  7],
 |              [ 8,  9, 10, 11]],
 |             [[12, 13, 14, 15],
 |              [16, 17, 18, 19],
 |              [20, 21, 22, 23]]])
 |      >>> y.strides
 |      (48, 16, 4)
 |      >>> y[1,1,1]
 |      17
 |      >>> offset=sum(y.strides * np.array((1,1,1)))
 |      >>> offset/y.itemsize
 |      17
 |      
 |      >>> x = np.reshape(np.arange(5*6*7*8), (5,6,7,8)).transpose(2,3,1,0)
 |      >>> x.strides
 |      (32, 4, 224, 1344)
 |      >>> i = np.array([3,5,2,2])
 |      >>> offset = sum(i * x.strides)
 |      >>> x[3,5,2,2]
 |      813
 |      >>> offset / x.itemsize
 |      813
 |  
 |  ----------------------------------------------------------------------
 |  Data and other attributes defined here:
 |  
 |  __hash__ = None
 |  
 |  __new__ = <built-in method __new__ of type object>
 |      T.__new__(S, ...) -> a new object with type S, a subtype of T


In [58]:
74+14.8+1.74


Out[58]:
90.53999999999999

In [ ]: