In [3]:
from __future__ import division, absolute_import #print_function
from scipy import signal
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import tables
from scipy.lib.six import xrange
from scipy.stats import norm, scoreatpercentile
from collections import OrderedDict
In [4]:
np.random.seed(31234232)
def frac_bwn(T=2, dt=0.01, sigma=0.05, S0=0.01, mu=0.1, plot=False):
N = round(T/dt)
t = np.linspace(0, T, N)
W = np.random.standard_normal(size = N)
W = np.cumsum(W)*np.sqrt(dt) ### standard brownian motion ###
X = (mu-0.5*sigma**2)*t + sigma*W
S = S0*np.exp(X) ### geometric brownian motion ###
if plot:
plt.plot(t, S)
plt.show()
return t, S
fbm_t, fbm_s = frac_bwn(T=1, dt=0.001, plot=True)
print len(fbm_s)
def brown_m(n):
# Process parameters
delta = 0.25
dt = 0.1
# Initial condition.
x = 0.0
for k in range(n):
x = x + norm.rvs(scale=delta**2*dt)
yield x
bwn_m = np.array([i for i in brown_m(1000)])
plot(bwn_m)
Out[4]:
In [ ]:
widths = np.arange(1, 100, 0.25)
sig = fbm_s
w_coefs_bwn = signal.cwt(sig, signal.ricker, widths)
w_coefs_bwn_la = -1 * log(abs(w_coefs_bwn))
In [8]:
plt.figure(figsize=(14,10))
plt.pcolor(w_coefs_bwn_la)
plt.colorbar()
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
In [ ]:
mask = create_w_coef_mask(w_coefs_bwn_la)
assert mask.shape == w_coefs_bwn_la.shape, (mask.shape, w_coefs_bwn_la.shape)
In [10]:
plt.figure(figsize=(14,10))
plt.pcolormesh(mask[:100,:100], cmap='Greys')
plt.colorbar()
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
In [12]:
test_sample = np.copy(mask)
bifucations = skeletor(test_sample, smallest_scale=2)
plt.figure(figsize=(14,10))
plt.pcolormesh(mask, cmap='Greys')
plt.colorbar()
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
plt.figure(figsize=(14,10))
for n, (k, v) in enumerate(bifucations.iteritems()):
rows, cols = zip(*v)
plt.plot(cols, rows)
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
In [17]:
len(bifucations)
Out[17]:
In [16]:
max_res = 100000
plt.figure(figsize=(14,14))
lst_color = 'r'
# sig = bwn_m # <-- this was already defined above
ts = range(len(sig))
offset_graphs = (max(sig) - min(sig)) / 2
extremas = sorted([t for num, t in bifucations.keys() if num < max_res])
for n in xrange(len(extremas)-1):
if lst_color == 'r':
lst_color = 'b'
elif lst_color == 'b':
lst_color = 'g'
else:
lst_color = 'r'
plt.plot(ts[extremas[n]:extremas[n+1]+1],
sig[extremas[n]:extremas[n+1]+1], c=lst_color)
plt.plot(extremas, sig[extremas]+offset_graphs, 'y')
plt.plot(ts, sig + (2*offset_graphs), 'b')
# plt.savefig('./example_clustering.png', dpi=5000)
plt.show()
# Top (blue) -> original signal
# Middle (yellow) -> piecewise vector representation
# Bottom (red/blue/green alternating) -> groupings based on the piecewise vector
In [7]:
def _sort_tuples(x, y):
if x[0] < y[0]:
return -1
elif x[0] == y[0]:
if x[1] > y[1]:
return -1
elif x[1] < y[1]:
return 1
else:
return 0
else:
return 1
def possible_direction(hood, proximity, center_row=3, center_col=3):
nzs = np.where(hood[:center_row] > 0)
#tuple of (abs-dist, value, (row, col))
matches = [(abs(row - center_row) + abs(col - center_col), hood[row,col], (row, col)) for row, col in zip(*nzs)]
matches.sort(cmp=_sort_tuples)
assert hood[center_row, center_col] != 0, matches
return matches
def walk_bifurcation(mtx, start_row, start_col, proximity=5, step=-1):
slope = 0
center_row, center_col = start_row, start_col
max_row, max_col = [i - 1 for i in mtx.shape]
trace_rt = []
while center_row > 0:
#get the prox bounds
right_bound = center_col + proximity + 1
left_bound = center_col - proximity
hood_center_col = proximity
if right_bound > max_col:
right_bound = max_col
elif left_bound < 0:
# edge case when the hood extends beyond the bounds of the matrix
# center in the hood is usually proximity, but if the left_bound is in conflict
# then we have to adjust the center. As left_bound is negative at this point,
# it is also the ammount of shift the center needs...
# eg:
# proximity = 3
# center_col = 2
# left_bound = -1
# hood[-1] = [0, 0, center, 0, 0 ,0] <-- hood[-1] is always hood_center_row
# thus hood_center_col need to have -1 applied (or just the invalid left_bound)
hood_center_col = proximity + left_bound
left_bound = 0
lower_bound = center_row - proximity
if lower_bound < 0:
# same arguement as above applies
hood_center_row = proximity + lower_bound
lower_bound = 0
else:
hood_center_row = proximity
# get the neighborhood...
hood = mtx[lower_bound:center_row+1, left_bound:right_bound]
# if center_row
# print_hood(hood)
# find the best choice for the ridge
try:
possibles = possible_direction(hood, proximity, center_row=hood_center_row, center_col=hood_center_col)
except AssertionError as e:
print e
print "Center (row, col)", center_row, center_col
print "bounds (lower, left, right)", lower_bound, left_bound, right_bound
print "hood (row, col)", hood_center_row, hood_center_col
print_hood(hood)
print trace_rt
raise ValueError("the bifucation walked has lost its tracking")
if not possibles:
return False, trace_rt
# print center_row, center_col, mtx[center_row, center_col]
# print trace_rt
# print_hood(hood)
# expand_hood = 5
# lower_bound = lower_bound - expand_hood if lower_bound - expand_hood > 0 else 0
# left_bound = left_bound - expand_hood if left_bound - expand_hood > 0 else 0
# right_bound = right_bound + expand_hood if right_bound + expand_hood < max_col else max_col
# print_hood(mtx[lower_bound:center_row, left_bound:right_bound])
# return None
# get the winner
match = possibles.pop(0)
#recompute the center and continue
match_hood_row, match_hood_col = match[2]
# TODO: we need to keep track of the movement of the curves
# match_hood_row < proximity always (this moves us up the matrix rows) but is always off by 1
center_row += match_hood_row - hood_center_row
# this can be +/- depending on the direction
center_col += match_hood_col - hood_center_col
# print center_row, center_col, mtx[center_row, center_col]
if center_row >= 0:
trace_rt.append((center_row, center_col))
else:
trace_rt.append((0, center_col))
if center_col == max_col or center_col == 0:
#If we end up on and edge, this is not a valid bifurcation
return False, trace_rt
return True, trace_rt
def print_hood(hood):
print hood
plt.figure(figsize=(14,10))
plt.pcolormesh(hood, cmap='Greys')
plt.colorbar()
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
def skeletor(mtx, proximity=9, smallest_scale=0):
'''
Skeleton Construction
proximity: defines region around the matrix
'''
# NB: scale <-> row
# NB: shift <-> col
max_row, max_col = mtx.shape
max_row -= 1
max_col -= 1
# holder for the ridges
bifurcations = OrderedDict()
invalids = OrderedDict()
bi_cnt = 0
for n, row_num in enumerate(xrange(max_row, smallest_scale, -1)):
# loop from the max-scale up
maxs = signal.argrelmax(mtx[row_num])[0]
#print "loop", n, "row_num", row_num, "maxs", maxs
if not maxs.any():
# Nothing here...
#print "exit", maxs.any()
continue
for start_pt in maxs:
continuous, bifurc_path = walk_bifurcation(mtx, row_num, start_pt, proximity=proximity)
# print row_num, start_pt, "cont", continuous, "bifurc_len", len(bifurc_path)
if continuous:
# add the bifurcation to the collector; key == row[0] intercept's column number
bifurcations[(bi_cnt, bifurc_path[-1][1])] = bifurc_path
bi_cnt += 1
elif bifurc_path:
invalids[bifurc_path[-1]] = bifurc_path
if len(bifurc_path):
#now zero out all of the entries that were used to walk the bifucation
rows_b, cols_b = zip(*bifurc_path)
rows_b = np.array(rows_b)
cols_b = np.array(cols_b)
# for d in range(-del_spread, del_spread):
mtx[rows_b, cols_b] = 0
return bifurcations
def create_w_coef_mask(w_coefs, epsilon=0.1, order=1):
mask = np.zeros_like(w_coefs, dtype=int)
epsilon = 0.1
for n, row in enumerate(w_coefs):
maxs = signal.argrelmax(row, order=order)[0]
mask[n, maxs] = row[maxs]/epsilon
return mask
In [209]:
foo = walk_bifurcation(small_samp, 49, 83)
rows, cols = zip(*foo)
plt.figure(figsize=(14,10))
plt.pcolormesh(small_samp, cmap='Greys')
plt.colorbar()
plt.plot(cols, rows)
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()
In [213]:
foo = walk_bifurcation(small_samp_2, 149, 883)
rows, cols = zip(*foo)
plt.figure(figsize=(14,10))
plt.pcolormesh(small_samp_2, cmap='Greys')
plt.colorbar()
plt.plot(np.array(cols) - 10, rows)
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
ax.xaxis.tick_top()
plt.show()