[numerics] NM_LU_solve: add preserve for generic mechanical test
@@ -319,7 +319,7 @@ void gmp_gauss_seidel(GenericMechanicalProblem* pGMP, double * reaction, double
for(size_t i = 0; i < curSize; ++i) sol[i] = -curProblem->q[i];
// resLocalSolver = NM_gesv(&M, sol, true);
- resLocalSolver = NM_LU_solve(&M, sol, 1);
+ resLocalSolver = NM_LU_solve(NM_preserve(&M), sol, 1);
M.matrix0 = NULL;
NM_clear(&M);
