Can anyone write step by step what should be done to do only backsubstitution or only forwardsubstitution ?
I tried to do backward substitution for a (nonsymmetric) SPARSE with nonzeros only in upper part of matrix (no nonzero values below diagonal). For this reason backardsubstitution should be enough.
so I tried to do it as in exapmle of nonsymetric real matrix:
mtype = 11, maxfct = 1; mnum = 1;
(1) PARDISO with phase = 11 (Reordering and Symbolic Factorization)
(2) PARDISO with phase = 22 (factorization)
(3) PARDISO with phase = 333 (backsubstitution only)
(4) PARDISO with phase = -2 (cleaning memoy)
and it did not work ... . When I gave 333 instead of 333 the result was correct.
 Shoud I do something more ?? some specyfic settings to use only phase = 333.
 What exactly is done in execution with phase = 33 (one backsubstitution and one forwardsubstitution and ... ?)