Added code to fit_line_emcee.py

[MaiAdityaHun]

No description provided.

[PhysicistSouravDas]

@MaiAdityaHun
Only writing return actually returns a None when this if condition satisfies, which will throw an error while running emcee. emcee always expects a float kind of data type to be returned by log_probability. Consider changing the if block with the following:

...
if not np.isfinite(lp):
    return -np.inf
...

[PhysicistSouravDas]

The else here is redundant, since a function only returns once, and whatever is returned, the function doesn't see any lines within it below the return. For example:

def f(x):
    if x >=0:
        return x**3
    else:  # when x < 0
        return x**2

The above function can be effectively written as:

def f(x):
    if x >=0:
        return x**3
    # when x < 0
    return x**2

And, in your last return statement, you are using log_prior(theta) again, which will again call the function and compute the value, but few lines above, you have already defined lp=log_prior(theta), which already computes the prior for a given theta and stores in lp. So, you can just write return lp + log_likelihood(theta, x, y, yerr). The way you have done is absolutely correct, but will waste computation if computing it is computationally costly.

[PhysicistSouravDas]

@MaiAdityaHun thanks for looking into the problem and submitting the PR. I have highlighted a few very minor changes which will make your PR better. Can you resolve those, commit a change and push it again? You can take your time.

Regards