python – scipy optimize.curve_fit cannot fit a function whose return value depends on a conditional

python – scipy optimize.curve_fit cannot fit a function whose return value depends on a conditional

Thats right, t < T is a boolean array. NumPy refuses to assign a truth value to boolean arrays because there are many possible choices — should it be True if all elements are True, or if any element is True?

But thats okay. In this case, NumPy provides a nice function to replace the if ... else ... blocks, namely, np.where:

def func(t, a0, a1, a2, T, tau1, tau2):
    return np.where(
        t < T,
        a0 + a1 * np.exp(-t/tau1) + a2 * np.exp(-t/tau2),
        a0 + a1 * np.exp(-T/tau1) * (1 - t/tau1 + T/tau1) + a2 * np.exp(-T/tau2) * (1 - t/tau2 + T/tau2) )

python – scipy optimize.curve_fit cannot fit a function whose return value depends on a conditional