approximate_function_double

Dirac-to-Dirac reduction with custom weight functions.

This variant allows user-defined Python callbacks to compute position-dependent weights and their derivatives.

Useful for:

• Structure-aware reduction
• Context-dependent weighting
• Experimental extensions

Required Callbacks

• wX(x): returns weight
• wXD(x): returns gradient of weight

Example

def wX(x):
    return np.exp(-np.sum(x**2))
 
def wXD(x):
    return -2 * x * np.exp(-np.sum(x**2))
 
result = d2d.approximate_function_double(
    y, M, L, N, x,
    wX=wX,
    wXD=wXD
)