From 1bff084127fbd671cfd05b26e418bcc539c909b3 Mon Sep 17 00:00:00 2001
From: Tapish <narwal83@hzdr.de>
Date: Mon, 23 Sep 2024 09:30:13 +0200
Subject: [PATCH] For a single thread acc if the WorkDiv number of threads per
 block is more than one, throw a runtime error

---
 include/alpaka/acc/AccCpuOmp2Blocks.hpp | 7 +++++++
 include/alpaka/acc/AccCpuSerial.hpp     | 7 +++++++
 include/alpaka/acc/AccCpuTbbBlocks.hpp  | 7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/include/alpaka/acc/AccCpuOmp2Blocks.hpp b/include/alpaka/acc/AccCpuOmp2Blocks.hpp
index df52d90d03bc..27661f58432a 100644
--- a/include/alpaka/acc/AccCpuOmp2Blocks.hpp
+++ b/include/alpaka/acc/AccCpuOmp2Blocks.hpp
@@ -189,6 +189,13 @@ namespace alpaka
                 TKernelFnObj const& kernelFnObj,
                 TArgs&&... args)
             {
+                if(workDiv.m_blockThreadExtent.prod() != static_cast<TIdx>(1u))
+                {
+                    throw std::runtime_error(
+                        "The given work division is not valid for a single thread Acc: "
+                        + getAccName<AccCpuOmp2Blocks<TDim, TIdx>>() + ". Threads per block should be 1!");
+                }
+
                 return TaskKernelCpuOmp2Blocks<TDim, TIdx, TKernelFnObj, TArgs...>(
                     workDiv,
                     kernelFnObj,
diff --git a/include/alpaka/acc/AccCpuSerial.hpp b/include/alpaka/acc/AccCpuSerial.hpp
index 4a4e8f0621a6..e1b223f89158 100644
--- a/include/alpaka/acc/AccCpuSerial.hpp
+++ b/include/alpaka/acc/AccCpuSerial.hpp
@@ -182,6 +182,13 @@ namespace alpaka
                 TKernelFnObj const& kernelFnObj,
                 TArgs&&... args)
             {
+                if(workDiv.m_blockThreadExtent.prod() != static_cast<TIdx>(1u))
+                {
+                    throw std::runtime_error(
+                        "The given work division is not valid for a single thread Acc: "
+                        + getAccName<AccCpuSerial<TDim, TIdx>>() + ". Threads per block should be 1!");
+                }
+
                 return TaskKernelCpuSerial<TDim, TIdx, TKernelFnObj, TArgs...>(
                     workDiv,
                     kernelFnObj,
diff --git a/include/alpaka/acc/AccCpuTbbBlocks.hpp b/include/alpaka/acc/AccCpuTbbBlocks.hpp
index 1d2c7aec5a58..d283523e7a5a 100644
--- a/include/alpaka/acc/AccCpuTbbBlocks.hpp
+++ b/include/alpaka/acc/AccCpuTbbBlocks.hpp
@@ -183,6 +183,13 @@ namespace alpaka
                 TKernelFnObj const& kernelFnObj,
                 TArgs&&... args)
             {
+                if(workDiv.m_blockThreadExtent.prod() != static_cast<TIdx>(1u))
+                {
+                    throw std::runtime_error(
+                        "The given work division is not valid for a single thread Acc: "
+                        + getAccName<AccCpuTbbBlocks<TDim, TIdx>>() + ". Threads per block should be 1!");
+                }
+
                 return TaskKernelCpuTbbBlocks<TDim, TIdx, TKernelFnObj, TArgs...>(
                     workDiv,
                     kernelFnObj,