only 2 SpMV in performHalpernPdhgStep

Author: Yanyu000

check/TestPdlp.cpp

@@ -474,7 +474,7 @@ TEST_CASE("cuda-sandbox", "[pdlp]") {
 #endif
 
 TEST_CASE("hi-pdlp-halpern", "[pdlp]") {
-  std::string model = "neso-2245";  //"afiro";
+  std::string model = "afiro";  //"afiro";
   // shell //stair //25fv47 //fit2p //avgas //neso-2245 //neso-2005
   std::string model_file =
       // std::string(HIGHS_DIR) + "/srv/" + model + ".mps.gz";

highs/pdlp/hipdlp/pdhg.cc

@@ -926,8 +926,7 @@ void PDLPSolver::performHalpernPdhgStep(bool is_major) {
     y_current_[j] = w * blended + (1.0 - w) * y_anchor_[j];
   }
 
-  // --- STEP 5: Recompute Ax, ATy for blended current ---
-  linalg::Ax(lp_, x_current_, Ax_cache_);
+  // --- STEP 5: Recompute ATy for blended current ---
   linalg::ATy(lp_, y_current_, ATy_cache_);
 }