Source code for astrophot.utils.optimization

import torch

from .. import AP_config




def chi_squared(target, model, mask=None, variance=None):
    if mask is None:
        if variance is None:
            return torch.sum((target - model) ** 2)
        else:
            return torch.sum(((target - model) ** 2) / variance)
    else:
        mask = torch.logical_not(mask)
        if variance is None:
            return torch.sum((target[mask] - model[mask]) ** 2)
        else:
            return torch.sum(((target[mask] - model[mask]) ** 2) / variance[mask])





def reduced_chi_squared(target, model, params, mask=None, variance=None):
    if mask is None:
        ndf = (
            torch.prod(
                torch.tensor(
                    target.shape, dtype=AP_config.ap_dtype, device=AP_config.ap_device
                )
            )
            - params
        )
    else:
        ndf = torch.sum(torch.logical_not(mask)) - params
    return chi_squared(target, model, mask, variance) / ndf