fronts.D.constant

fronts.D.constant(D0)

Return a constant D function.

Given \(D_0\), returns the function D:

\[D(\theta) = D_0\]

Parameters:

D0 (float) – \(D_0\), a positive constant

Returns:

D –

Function to evaluate \(D\) and its derivatives:

• D(theta) evaluates and returns \(D\) at theta

• D(theta, 1) returns both the value of \(D\) and its first derivative at theta

• D(theta, 2) returns the value of \(D\), its first derivative, and its second derivative at theta

In all cases, the argument theta may be a single float or a NumPy array.

Return type:

callable

Notes

This function is not particularly useful: a constant D will turn a diffusion problem into a linear one, which has an exact solution and no numerical solvers are necessary. However, it is provided here given that it is the simplest supported function.