Fitting Models Exercise 1

Imports


In [ ]:
%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np
import scipy.optimize as opt

Fitting a quadratic curve

For this problem we are going to work with the following model:

$$ y_{model}(x) = a x^2 + b x + c $$

The true values of the model parameters are as follows:


In [ ]:
a_true = 0.5
b_true = 2.0
c_true = -4.0

First, generate a dataset using this model using these parameters and the following characteristics:

  • For your $x$ data use 30 uniformly spaced points between $[-5,5]$.
  • Add a noise term to the $y$ value at each point that is drawn from a normal distribution with zero mean and standard deviation 2.0. Make sure you add a different random number to each point (see the size argument of np.random.normal).

After you generate the data, make a plot of the raw data (use points).


In [ ]:
# YOUR CODE HERE
raise NotImplementedError()

In [ ]:
assert True # leave this cell for grading the raw data generation and plot

Now fit the model to the dataset to recover estimates for the model's parameters:

  • Print out the estimates and uncertainties of each parameter.
  • Plot the raw data and best fit of the model.

In [ ]:
# YOUR CODE HERE
raise NotImplementedError()

In [ ]:
assert True # leave this cell for grading the fit; should include a plot and printout of the parameters+errors