Node parallelism off for subtrees

Author: filikat

highs/ipm/hipo/factorhighs/Factorise.cpp

@@ -195,11 +195,13 @@ void Factorise::processSupernode(Int sn, bool parallelise) {
 
   if (flag_stop_) return;
 
-  if (parallelise) {
+  bool do_parallelise = parallelise;
+
+  if (do_parallelise) {
     // if there is only one child, do not parallelise
     if (first_child_[sn] != -1 && next_child_[first_child_[sn]] == -1) {
       spawnNode(first_child_[sn], tg, false);
-      parallelise = false;
+      do_parallelise = false;
     } else {
       // spawn children of this supernode in reverse order
       Int child_to_spawn = first_child_reverse_[sn];
@@ -266,7 +268,7 @@ void Factorise::processSupernode(Int sn, bool parallelise) {
     // Schur contribution of the current child
     std::vector<double>& child_clique = schur_contribution_[child_sn];
 
-    if (parallelise) {
+    if (do_parallelise) {
       // sync with spawned child, apart from the first one
       if (child_sn != first_child_[sn]) syncNode(child_sn, tg);
 
@@ -351,7 +353,10 @@ void Factorise::processSupernode(Int sn, bool parallelise) {
   // const double reg_thresh = max_diag_ * kDynamicDiagCoeff;
   const double reg_thresh = A_norm1_ * kDynamicDiagCoeff;
 
-  if (Int flag = FH->denseFactorise(reg_thresh)) {
+  // Node-level parallelism is off if in a subtree
+  bool node_parallel = parallelise && S_.parNode();
+
+  if (Int flag = FH->denseFactorise(reg_thresh, node_parallel)) {
     flag_stop_ = true;
 
     if (log_ && flag == kRetInvalidInput)

highs/ipm/hipo/factorhighs/FormatHandler.h

@@ -80,7 +80,7 @@ class FormatHandler {
                                        Int j) = 0;
   virtual void assembleClique(const std::vector<double>& child, Int nc,
                               Int child_sn) = 0;
-  virtual Int denseFactorise(double reg_thresh) = 0;
+  virtual Int denseFactorise(double reg_thresh, bool parallelise) = 0;
 
   // =================================================================
   // Virtual functions.

highs/ipm/hipo/factorhighs/HybridHybridFormatHandler.cpp

@@ -57,7 +57,8 @@ void HybridHybridFormatHandler::assembleFrontalMultiple(
                     &frontal_[diag_start_[block] + ii + ldb * jj], 1, data_);
 }
 
-Int HybridHybridFormatHandler::denseFactorise(double reg_thresh) {
+Int HybridHybridFormatHandler::denseFactorise(double reg_thresh,
+                                              bool parallelise) {
   Int status;
 
   status = denseFactFP2FH(frontal_.data(), ldf_, sn_size_, nb_, data_);
@@ -70,7 +71,7 @@ Int HybridHybridFormatHandler::denseFactorise(double reg_thresh) {
   status = denseFactFH('H', ldf_, sn_size_, S_->blockSize(), frontal_.data(),
                        clique_.data(), pivot_sign, reg_thresh, regul_,
                        local_reg_.data(), swaps_.data(), pivot_2x2_.data(),
-                       S_->parNode(), data_);
+                       parallelise, data_);
 
   return status;
 }

highs/ipm/hipo/factorhighs/HybridHybridFormatHandler.h

@@ -16,7 +16,7 @@ class HybridHybridFormatHandler : public FormatHandler {
   void assembleFrontalMultiple(Int num, const std::vector<double>& child,
                                Int nc, Int child_sn, Int row, Int col, Int i,
                                Int j) override;
-  Int denseFactorise(double reg_thresh) override;
+  Int denseFactorise(double reg_thresh, bool parallelise) override;
   void assembleClique(const std::vector<double>& child, Int nc,
                       Int child_sn) override;
   void extremeEntries() override;