From 55c064de28d9a9ac6ddc305dba45f449d81a70ea Mon Sep 17 00:00:00 2001
From: Peter Boyle <paboyle@ph.ed.ac.uk>
Date: Fri, 14 Aug 2026 17:51:40 -0400
Subject: [PATCH] Batch blas test extension

---
 tests/debug/Test_batched_blas.cc | 78 ++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/tests/debug/Test_batched_blas.cc b/tests/debug/Test_batched_blas.cc
index 474dcaf5a..243b94ac0 100644
--- a/tests/debug/Test_batched_blas.cc
+++ b/tests/debug/Test_batched_blas.cc
@@ -250,6 +250,84 @@ int main (int argc, char ** argv)
     GRID_ASSERT(rel < 1.0e-4);
   }
 
+  ////////////////////////////////////////////////////////////////
+  // T3 : ComplexD explicit-ld gemmBatched (the RecursiveSchurInverse
+  // merge primitive): same split-K miniature as T2, double precision.
+  // On device builds this is the FIRST exercise of hipblasZ/cublasZ
+  // gemmBatched through the strided overload.
+  ////////////////////////////////////////////////////////////////
+  {
+    const int nrows = 8;
+    const int nrhs  = 4;
+    const int K     = 256;
+    const int NK    = 8;        // split-K chunks
+    const int Kc    = K/NK;
+
+    std::vector<ComplexD> Ahost((uint64_t)K*nrows);
+    std::vector<ComplexD> Xhost((uint64_t)K*nrhs);
+    for(auto &z : Ahost) z = ComplexD(dist(rng),dist(rng));
+    for(auto &z : Xhost) z = ComplexD(dist(rng),dist(rng));
+
+    deviceVector<ComplexD> Adev(Ahost.size());
+    deviceVector<ComplexD> Xdev(Xhost.size());
+    deviceVector<ComplexD> Yref((uint64_t)nrows*nrhs);
+    deviceVector<ComplexD> Ypart((uint64_t)NK*nrows*nrhs);
+    acceleratorCopyToDevice(&Ahost[0],&Adev[0],Ahost.size()*sizeof(ComplexD));
+    acceleratorCopyToDevice(&Xhost[0],&Xdev[0],Xhost.size()*sizeof(ComplexD));
+
+    ComplexD one (1.0,0.0);
+    ComplexD zero(0.0,0.0);
+
+    // (a) reference: one compact batch=1 call (compact lda == K for OP_T)
+    {
+      deviceVector<ComplexD*> Ap(1), Xp(1), Yp(1);
+      std::vector<ComplexD*> h(1);
+      h[0]=&Adev[0]; acceleratorCopyToDevice(&h[0],&Ap[0],sizeof(ComplexD*));
+      h[0]=&Xdev[0]; acceleratorCopyToDevice(&h[0],&Xp[0],sizeof(ComplexD*));
+      h[0]=&Yref[0]; acceleratorCopyToDevice(&h[0],&Yp[0],sizeof(ComplexD*));
+      blas.gemmBatched(GridBLAS_OP_T,GridBLAS_OP_N,
+                       nrows,nrhs,K,
+                       one, Ap, Xp, zero, Yp);
+      blas.synchronise();
+    }
+
+    // (b) split-K: NK chunk-pointers into the SAME allocations, lda/ldb = K
+    {
+      deviceVector<ComplexD*> Ap(NK), Xp(NK), Yp(NK);
+      std::vector<ComplexD*> h(NK);
+      for(int j=0;j<NK;j++) h[j] = &Adev[(uint64_t)j*Kc];        // K-offset slice
+      acceleratorCopyToDevice(&h[0],&Ap[0],NK*sizeof(ComplexD*));
+      for(int j=0;j<NK;j++) h[j] = &Xdev[(uint64_t)j*Kc];
+      acceleratorCopyToDevice(&h[0],&Xp[0],NK*sizeof(ComplexD*));
+      for(int j=0;j<NK;j++) h[j] = &Ypart[(uint64_t)j*nrows*nrhs];
+      acceleratorCopyToDevice(&h[0],&Yp[0],NK*sizeof(ComplexD*));
+      blas.gemmBatched(GridBLAS_OP_T,GridBLAS_OP_N,
+                       nrows,nrhs,Kc,
+                       one, Ap, /*lda*/ K,
+                            Xp, /*ldb*/ K,
+                       zero,Yp, /*ldc*/ nrows);
+      blas.synchronise();
+    }
+
+    std::vector<ComplexD> Yref_h((uint64_t)nrows*nrhs);
+    std::vector<ComplexD> Ypart_h((uint64_t)NK*nrows*nrhs);
+    acceleratorCopyFromDevice(&Yref[0], &Yref_h[0], Yref_h.size()*sizeof(ComplexD));
+    acceleratorCopyFromDevice(&Ypart[0],&Ypart_h[0],Ypart_h.size()*sizeof(ComplexD));
+
+    double maxdev = 0.0;
+    double maxval = 0.0;
+    for(int i=0;i<nrows*nrhs;i++){
+      ComplexD sum(0.0,0.0);
+      for(int j=0;j<NK;j++) sum = sum + Ypart_h[(uint64_t)j*nrows*nrhs + i];
+      maxdev = std::max(maxdev,(double)abs(sum-Yref_h[i]));
+      maxval = std::max(maxval,(double)abs(Yref_h[i]));
+    }
+    double rel = maxdev/maxval;
+    std::cout << GridLogMessage << "T3  split-K strided gemmBatched ComplexD  max rel dev vs compact = "
+              << rel << ( rel < 1.0e-13 ? "   PASS" : "   FAIL" ) << std::endl;
+    GRID_ASSERT(rel < 1.0e-13);
+  }
+
   std::cout << GridLogMessage << "All batched-blas tests PASSED" << std::endl;
 
   Grid_finalize();