Merge pull request #146 from psteinb/add_selfcontained_sample

create stub folder that contains a minimal example on how to use rocfft

docs/samples/CMakeLists.txt

@@ -0,0 +1,27 @@
+CMAKE_MINIMUM_REQUIRED(VERSION 3.0)
+
+# project name
+PROJECT(rocfft_samples CXX)
+
+find_package(hip)
+find_package(rocfft)
+
+add_executable(complex_forward_1d complex_forward_1d.cpp)
+target_link_libraries( complex_forward_1d PRIVATE roc::rocfft hip::hip_hcc )
+target_include_directories( complex_forward_1d PRIVATE ${rocfft_INCLUDE_DIR} )
+set_target_properties( complex_forward_1d PROPERTIES
+  CXX_STANDARD_REQUIRED ON)
+set_target_properties( complex_forward_1d PROPERTIES
+  CXX_STANDARD 14)
+
+if( CMAKE_CXX_COMPILER MATCHES ".*/hcc$" )
+  # Remove following when hcc is fixed; hcc emits following spurious warning ROCm v1.6.1
+  # "clang-5.0: warning: argument unused during compilation: '-isystem /opt/rocm/include'"
+  target_compile_options( complex_forward_1d PRIVATE -Wno-unused-command-line-argument )
+  set_target_properties( complex_forward_1d PROPERTIES
+    CXX_EXTENSIONS OFF)
+
+  # foreach( target ${AMDGPU_TARGETS} )
+  #   target_link_libraries( rocfft-selftest PRIVATE --amdgpu-target=${target} )
+  # endforeach( )
+endif( )

docs/samples/README.md

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+# Samples to demo using rocfft
+
+## `complex_forward_1d`
+
+``` bash
+$ mkdir build
+$ cmake ..
+$ make
+```
+

docs/samples/complex_forward_1d.cpp

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+#include <stdio.h>
+#include <vector>
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <hip/hip_runtime_api.h>
+#include "rocfft.h"
+
+
+int main()
+{
+    // For size N <= 4096
+    const size_t N = 16;
+
+    std::vector<float2> cx(N);
+
+    for (size_t i = 0; i < N; i++)
+    {
+        cx[i].x = (i%3) - (i%7);
+        cx[i].y = 0;
+    }
+
+    // rocfft gpu compute
+    // ========================================
+
+    rocfft_setup();
+
+    size_t Nbytes = N * sizeof(float2);
+
+    // Create HIP device object.
+    float2 *x;
+    hipMalloc(&x, Nbytes);
+
+    //  Copy data to device
+    hipMemcpy(x, &cx[0], Nbytes, hipMemcpyHostToDevice);
+
+    // Create plan
+    rocfft_plan plan = NULL;
+    size_t length = N;
+    rocfft_plan_create(&plan, rocfft_placement_inplace, rocfft_transform_type_complex_forward, rocfft_precision_single, 1, &length, 1, NULL);
+
+    // Execute plan
+    rocfft_execute(plan, (void**)&x, NULL, NULL);
+
+    // Destroy plan
+    rocfft_plan_destroy(plan);
+
+    // Copy result back to host
+    std::vector<float2> y(N);
+    hipMemcpy(&y[0], x, Nbytes, hipMemcpyDeviceToHost);
+    hipFree(x);
+
+    rocfft_cleanup();
+
+    for( size_t i = 0;i < N;++i){
+        if(std::abs( cx[i].x - y[i].x ) < 1e-5){
+            std::cerr << "Error - unexpected matching element: observed " << y[i].x << ", expected " <<  cx[i].x << std::endl;
+            return 1;
+        }
+    }
+
+    std::cout << "complex forward 1d - OK!" << std::endl;
+
+    return 0;
+}