changed normlizaton factor in CUDA codegen

tests/cuda/codegen/CodegenJacobiGPU.cpp

@@ -78,7 +78,7 @@ void testJacobi2D()
    // Create blocks
    shared_ptr< StructuredBlockForest > blocks = blockforest::createUniformBlockGrid (
            uint_t(1) , uint_t(1),  uint_t(1),  // number of blocks in x,y,z direction
-           xSize, ySize, uint_t(1),  // how many cells per block (x,y,z)
+           xSize, ySize, uint_t(1),            // how many cells per block (x,y,z)
            real_t(1),                          // dx: length of one cell in physical coordinates
            false,                              // one block per process - "false" means all blocks to one process
            true, true, true );                 // no periodicity
@@ -87,7 +87,8 @@ void testJacobi2D()
    BlockDataID cpuFieldID = blocks->addStructuredBlockData<ScalarField>( &createField, "CPU Field" );
    BlockDataID gpuField = cuda::addGPUFieldToStorage<ScalarField>( blocks, cpuFieldID, "GPU Field Src" );
 
-
+   // Initialize a quarter of the field with ones, the rest remains 0
+   // Jacobi averages the domain -> every cell should be at 0.25 at sufficiently many timesteps
    for(auto blockIt = blocks->begin(); blockIt != blocks->end(); ++blockIt)
    {
       auto f = blockIt->getData<ScalarField>( cpuFieldID );
@@ -96,8 +97,6 @@ void testJacobi2D()
             f->get( x, y, 0 ) = 1.0;
    }
 
-
-
    typedef blockforest::communication::UniformBufferedScheme<stencil::D2Q9> CommScheme;
    typedef cuda::communication::GPUPackInfo<GPUField> Packing;
 
@@ -110,7 +109,7 @@ void testJacobi2D()
 
    // Registering the sweep
    timeloop.add() << BeforeFunction(  commScheme, "Communication" )
-                  << Sweep( pystencils::CudaJacobiKernel2D(gpuField, 1.0), "Jacobi Kernel" );
+                  << Sweep( pystencils::CudaJacobiKernel2D(gpuField, 2.0), "Jacobi Kernel" );
 
 
    cuda::fieldCpy<GPUField, ScalarField>( blocks, gpuField, cpuFieldID );
@@ -141,7 +140,8 @@ void testJacobi3D()
    BlockDataID cpuFieldID = blocks->addStructuredBlockData<ScalarField>( &createField, "CPU Field" );
    BlockDataID gpuField = cuda::addGPUFieldToStorage<ScalarField>( blocks, cpuFieldID, "GPU Field Src" );
 
-
+   // Initialize a quarter of the field with ones, the rest remains 0
+   // Jacobi averages the domain -> every cell should be at 0.25 at sufficiently many timesteps
    for(auto blockIt = blocks->begin(); blockIt != blocks->end(); ++blockIt)
    {
       auto f = blockIt->getData<ScalarField>( cpuFieldID );
@@ -151,8 +151,6 @@ void testJacobi3D()
                f->get( x, y, z ) = 1.0;
    }
 
-
-
    typedef blockforest::communication::UniformBufferedScheme<stencil::D3Q7> CommScheme;
    typedef cuda::communication::GPUPackInfo<GPUField> Packing;
 

tests/cuda/codegen/CudaJacobiKernel.py

@@ -7,11 +7,11 @@ with CodeGeneration() as ctx:
     h = sp.symbols("h")
 
     # ----- Jacobi 2D - created by specifying weights in nested list --------------------------
-    src, dst = ps.fields("src, src_tmp: [2D]")
-    stencil = [[0, 1, 0],
-               [1, 0, 1],
-               [0, 1, 0]]
-    assignments = ps.assignment_from_stencil(stencil, src, dst, normalization_factor=0.25 * h**2)
+    src, dst = ps.fields("src, src_tmp: [2D]", layout='fzyx')
+    stencil = [[0, 4, 0],
+               [4, 0, 4],
+               [0, 4, 0]]
+    assignments = ps.assignment_from_stencil(stencil, src, dst, normalization_factor=1 / (4 * h ** 2))
     generate_sweep(ctx, 'CudaJacobiKernel2D', assignments, field_swaps=[(src, dst)], target="gpu")
 
     # ----- Jacobi 3D - created by using kernel_decorator with assignments in '@=' format -----

tests/field/codegen/JacobiKernel.py

@@ -21,6 +21,6 @@ with CodeGeneration() as ctx:
     def kernel_func():
         dst[0, 0, 0] @= (src[1, 0, 0] + src[-1, 0, 0] +
                          src[0, 1, 0] + src[0, -1, 0] +
-                         src[0, 0, 1] + src[0, 0, -1]) / (h ** 2 * 6)
+                         src[0, 0, 1] + src[0, 0, -1]) / (6 * h ** 2)
 
     generate_sweep(ctx, 'JacobiKernel3D', kernel_func, field_swaps=[(src, dst)])