proximal_operator

xrayvision.mem.proximal_operator(z, f, m, lamb, Lip, niter=250)

Computes the value of the proximity operator of the entropy function subject to positivity constraint and flux constraint by means of a Dykstra-like proximal algorithm (see Combettes, Pesquet, “Proximal Splitting Methods in Signal Processing”, (2011)). The problem to solve is:

argmin_x 1/2*|| x - y ||^2 + lambda/Lip * H(x)

subject to positivity constraint and flux constraint.

Parameters:

• z

• f

• m

• lamb

• Lip

• niter