Ready for fvm steady case

include/numerics/matmul.h

@@ -85,21 +85,23 @@ utils::Matrix<T> matmul_auto(const utils::Matrix<T>& A,
     const uint64_t m=A.rows(), p=B.cols();
     const uint64_t work = m * p;
 
-    bool can_parallel = omp_config::omp_parallel_allowed();
+    
 
     #ifdef _OPENMP
-      int threads = omp_get_max_threads();
+    bool can_parallel = omp_config::omp_parallel_allowed();
+      uint64_t threads = static_cast<uint64_t>(omp_get_max_threads());
     #else
-      int threads = 1;
+      bool can_parallel = false;
+      uint64_t threads = 1;
     #endif
 
 
     // Tiny problems: serial is cheapest.
-    if (!can_parallel || work < static_cast<uint64_t>(threads)*4ull) {
+    if (!can_parallel || work < threads*4ull) {
         return matmul(A,B);
     }
     // Plenty of (i,j) work → collapse(2) is a great default.
-    else if (work >= 8ull * static_cast<uint64_t>(threads)) {
+    else if (work >= 8ull * threads) {
         return matmul_collapse_omp(A,B);
     }
     // Many rows and very few columns → rows-only cheaper overhead.