From 812d360e2470c896c948bd3f5ff89acc0e054f8f Mon Sep 17 00:00:00 2001
From: antonl <anton.ljungdahl@gmail.com>
Date: Thu, 5 Feb 2026 10:10:27 +0100
Subject: [PATCH] working with mpi compile on main, initialising MPI on main
 and calling mpi functions on library

---
 build.bat        |  8 ++++----
 src/commlayer.cu | 10 ++++------
 src/main.cu      | 51 +++++++++++++++++++++++++++++++++++-------------
 3 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/build.bat b/build.bat
index c39e0c0..e930a94 100644
--- a/build.bat
+++ b/build.bat
@@ -1,4 +1,4 @@
-@rem @echo off
+@echo off
 setlocal
 
 @rem I rely on environment variables here.
@@ -22,7 +22,7 @@ set CudaLibPaths=-L"%CUDA_PATH%\lib\x64" -L"%CUDSS_PATH%\lib\12"
 
 set LibraryLinks=-lcudss -lcudart
 
-nvcc -v -c -o build/%commLayerSource%.obj src/%commLayerSource%.cu ^
+nvcc -c -o build/%commLayerSource%.obj src/%commLayerSource%.cu ^
     -arch=%nvccArch% ^
      %CudaIncludes% %OtherIncludes% %MPIIncludes% %CudaLibPaths% %MPILibPath% ^
     %LibraryLinks% ^
@@ -48,8 +48,8 @@ if %ERRORLEVEL% NEQ 0 (
 
 nvcc -o build/%mainSource% src/%mainSource%.cu ^
     -arch=%nvccArch% ^
-     %CudaIncludes% %OtherIncludes% %CudaLibPaths% ^
-    -lcudss -lcudart ^
+     %CudaIncludes% %OtherIncludes% %CudaLibPaths% %MPIIncludes% %MPILibPath% ^
+    -lcudss -lcudart -lmsmpi ^
     %IgnoreWarnings% ^
     -Xcompiler %ExeXcompilerFlags%
 
diff --git a/src/commlayer.cu b/src/commlayer.cu
index 882b74c..c5211dc 100644
--- a/src/commlayer.cu
+++ b/src/commlayer.cu
@@ -3,6 +3,8 @@
 
 #include <mpi.h>
 
+#include "cudss.h"
+
 #define __CSCUDSS_EXPORT extern "C" __declspec(dllexport)
 
 
@@ -18,20 +20,16 @@ __CSCUDSS_EXPORT int cudssCommSize(void *comm, int *size) {
 
 
 
-__CSCUDSS_EXPORT int libraryMain() {
+__CSCUDSS_EXPORT int libraryMain(void) {
 
-  MPI_Init(0,0);
-  std::cout << "HELLO LIBRARY" << std::endl;
-  
   int rank;
   int size;
   int Comm = MPI_COMM_WORLD;
   cudssCommRank(&Comm, &rank);
   cudssCommSize(&Comm, &size);
 
-  std::cout << "Rank: " << rank << ", size: " << size << std::endl;
+  std::cout << "Entered library for Rank: " << rank << ", size: " << size << std::endl;
 
-  MPI_Finalize();
   return 0;
 
 }
diff --git a/src/main.cu b/src/main.cu
index b5d461c..6492d0e 100644
--- a/src/main.cu
+++ b/src/main.cu
@@ -6,13 +6,17 @@
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
+#include <mpi.h>
+
 #include "util.h"
 
 /* ============================================================================
  * Version Information
  * ============================================================================ */
 
-void printCudaVersion(void) {
+void printCudaVersion(int rank) {
+    if(rank !=0) return;
+
     int runtimeVersion = 0;
     int driverVersion = 0;
     
@@ -29,7 +33,9 @@ void printCudaVersion(void) {
     LOG("CUDA Driver Version:  %d.%d", driverMajor, driverMinor);
 }
 
-void printCudssVersion(void) {
+void printCudssVersion(int rank) {
+    if(rank !=0) return;
+
     int major = 0;
     int minor = 0;
     int patch = 0;
@@ -41,7 +47,9 @@ void printCudssVersion(void) {
     LOG("cuDSS Version: %d.%d.%d", major, minor, patch);
 }
 
-void printDeviceInfo(void) {
+void printDeviceInfo(int rank) {
+    if(rank !=0) return;
+
     int deviceCount = 0;
     CUDA_CHECK(cudaGetDeviceCount(&deviceCount));
     
@@ -67,13 +75,22 @@ void printDeviceInfo(void) {
 using libraryMain = int(*)();
 
 int main(int argc, char **argv) {
-    LOG("cuDSS Test Program");
-    LOG("==================");
-    
+
+    MPI_Init(0,0);
+    int rank;
+    int size;
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+
+    if(rank == 0) {
+      LOG("cuDSS Test Program");
+      LOG("==================");
+    }
+
     /* Print version information */
-    printCudaVersion();
-    printCudssVersion();
-    printDeviceInfo();
+    printCudaVersion(rank);
+    printCudssVersion(rank);
+    printDeviceInfo(rank);
     
     HMODULE hLib = LoadLibraryA("commlayer.dll");
     if (!hLib) {
@@ -92,12 +109,18 @@ int main(int argc, char **argv) {
     /* Initialize cuDSS */
     cudssHandle_t handle = NULL;
     CUDSS_CHECK(cudssCreate(&handle));
-    LOG("cuDSS handle created successfully");
-       
+    if(rank == 0) {
+      LOG("cuDSS handle created successfully");
+    }
     /* Cleanup */
     CUDSS_CHECK(cudssDestroy(handle));
-    LOG("cuDSS handle destroyed");
-    
-    LOG("Done.");
+    if(rank == 0) {
+      LOG("cuDSS handle destroyed");
+    }
+
+    MPI_Finalize();
+    if(rank == 0) {
+      LOG("Done.");
+    }
     return 0;
 }