primal_dual_hybrid_gradient solver: why compute derivative ?
Zeqiang-Lai opened this issue · comments
Zeqiang Lai commented
I just could not make correspondence between the math and implementation of PDHG.
It seems that we do not need to compute gradient when update x
Sebastian Banert commented
The derivative of a linear operator is the operator itself, so this surely doesn't harm anything. On the other hand, the code in this form also works for a non-linear operator, e.g.,