Added OpenMP code samples for gemm and LU decomposition(Doolittle algorithm)

gemm/gemm_openmp/CMakeLists.txt

+# ==================================================================================================
+# This file is part of the CodeVault project. The project is licensed under Apache Version 2.0.
+# CodeVault is part of the EU-project PRACE-4IP (WP7.3.C).
+#
+# Author(s):
+#  Rafal Gandecki <rafal.gandeci@pwr.edu.nl>
+#
+# ==================================================================================================
+ 
+cmake_minimum_required(VERSION 2.8.7 FATAL_ERROR)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../cmake/common.cmake)
+ 
+# ==================================================================================================
+if ("${DWARF_PREFIX}" STREQUAL "")
+  set(DWARF_PREFIX gemm_openmp)
+endif()
+ 
+find_package(Common)
+find_package(OpenMP)
+enable_language (C)
+ 
+ 
+set(NAME ${DWARF_PREFIX})
+ 
+if (OPENMP_FOUND)
+  set(CXX_FLAGS "${CXX_FLAGS} -Wall -Wno-comment -std=c++0x -fopenmp")
+  set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_FLAGS}")
+  add_executable(${NAME} src/gemm_openmp.cpp)
+  install(TARGETS ${NAME} DESTINATION bin)
+
+else ()
+  message("## Skipping '${NAME}': no OpenMP support found")
+endif()
+
+unset(NAME)

gemm/gemm_openmp/README.md

+README
+=======
+ 
+# 1. Code sample name
+gemm_openmp
+ 
+# 2. Description of the code sample package
+This example demonstrates the use of OpenMP for matrix-matrix multiplication.
+ 
+# 3. Release date
+19 August 2016
+ 
+# 4. Version history
+1.0
+ 
+# 6. Copyright / License of the code sample
+Apache Version 2.0
+ 
+# 5. Contributor (s) / Maintainer(s)
+Rafal Gandecki <rafal.gandecki@pwr.edu.pl>
+ 
+# 7. Language(s)
+C++ 11
+ 
+# 8. Parallelisation Implementation(s)
+OpenMP
+ 
+# 9. Level of the code sample complexity
+basic
+ 
+# 10. Instructions on how to compile the code
+Uses the CodeVault CMake infrastructure, see main README.md
+ 
+# 11. Instructions on how to run the code
+Just run compiled executable
+ 
+# 12. Sample input(s)
+3 arguments:
+- matrix A rows
+- matrix A cols
+- matrix B cols
+
+# 13. Sample output(s)
+execution time of algorithm wih and wihout OpenMP

gemm/gemm_openmp/src/gemm_openmp.cpp

+// =================================================================================================
+// This file is part of the CodeVault project. The project is licensed under Apache Version 2.0.
+// CodeVault is part of the EU-project PRACE-4IP (WP7.3.C).
+//
+// Author(s):
+//   Rafal Gandecki <rafal.gandecki@pwr.edu.pl>
+//
+// This example demonstrates the use of OpenMP for matrix-matrix multiplication and
+// compares execution time of algorithms.
+// The example is set-up to perform single precision matrix-matrix multiplication.
+// The example takes a triple input arguments (matrix A rows, matrix A cols, matric B cols),
+// specifying the size of the matrices.
+// See [http://www.openmp.org/] for the full OpenMP documentation.
+//
+// =================================================================================================
+
+#include <omp.h>
+#include <random>
+#include <iostream>
+
+void fill_random(float *A, const int &n, const int &m)
+{
+  std::mt19937 e(static_cast<unsigned int>(time(nullptr)));
+  std::uniform_real_distribution<float> f;
+  for(int i=0; i<n; ++i)
+  {
+    for(int j=0; j<m; ++j)
+    {
+      A[i*m+j] = f(e);
+    }
+  }
+}
+
+void gemm(float *A, float *B, float *C, 
+          const int &A_rows, const int &A_cols, const int &B_rows)
+{
+  for(int i=0; i<A_rows; i++)
+  {
+    for(int j=0; j<B_rows; j++) {
+      float sum = 0.0;
+      for (int k=0; k<A_cols; k++) {
+        sum += A[i*A_cols+k] * B[k*B_rows+j];
+      }
+      C[i*B_rows+j ] = sum;
+    }
+  }
+}
+
+void gemm_OpenMP(float *A, float *B, float *C,
+                 const int &A_rows, const int &A_cols, const int &B_rows)
+{
+  int i, j, k;
+  #pragma omp parallel for shared(A, B, C, A_rows, A_cols, B_rows) private(i, j, k)
+  for (i = 0; i < A_rows; i++)
+  {
+    for (j = 0; j < B_rows; j++)
+    {
+      float sum  = 0.0;
+      for (k=0; k<A_cols; k++)
+      {
+        sum += A[i*A_cols+k] * B[k*B_rows+j];
+      }
+      C[i*B_rows+j] = sum;
+    }
+  }
+}
+
+int main(int argc, char **argv)
+{
+  int A_rows, A_cols, B_rows, B_cols;
+    
+  if (argc != 4)
+  {
+    std::cout << "Usage: 3 arguments: matrix A rows, matrix A cols and matrix B cols"<< std::endl;
+    return 1;
+  }
+  else
+  {
+    A_rows = atoi(argv[1]);
+    A_cols = atoi(argv[2]);
+    B_rows = atoi(argv[2]);
+    B_cols = atoi(argv[3]);
+  }
+
+  double dtime;
+
+  float *A = new float[A_rows*A_cols];
+  float *B = new float[B_rows*B_cols];
+  float *C = new float[A_rows*B_cols];
+
+  fill_random(A, A_rows, A_cols);
+  fill_random(B, B_rows, B_cols);
+
+  dtime = omp_get_wtime();
+  gemm_OpenMP(A, B, C, A_rows, A_cols, B_cols);
+  dtime = omp_get_wtime() - dtime;
+  std::cout << "Time with OpenMp: " << dtime << std::endl;
+
+  dtime = omp_get_wtime();
+  gemm(A,B,C, A_rows, A_cols, B_cols);
+  dtime = omp_get_wtime() - dtime;
+  std::cout << "Time without OpenMP: " << dtime << std::endl;
+
+  delete[] A;
+  delete[] B;
+  delete[] C;
+  return 0;
+}
+

lud/lud_openmp/CMakeLists.txt

+# ==================================================================================================
+# This file is part of the CodeVault project. The project is licensed under Apache Version 2.0.
+# CodeVault is part of the EU-project PRACE-4IP (WP7.3.C).
+#
+# Author(s):
+#  Rafal Gandecki <rafal.gandeci@pwr.edu.nl>
+#
+# ==================================================================================================
+
+cmake_minimum_required(VERSION 2.8.7 FATAL_ERROR)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../cmake/common.cmake)
+
+# ==================================================================================================
+if ("${DWARF_PREFIX}" STREQUAL "")
+  set(DWARF_PREFIX lud_openmp)
+endif()
+
+find_package(Common)
+find_package(OpenMP)
+enable_language (C)
+
+set(NAME ${DWARF_PREFIX})
+
+if (OPENMP_FOUND)
+  set(CXX_FLAGS "${CXX_FLAGS} -Wall -Wno-comment -std=c++0x -fopenmp")
+  set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_FLAGS}")
+  add_executable(${NAME} src/lud_openmp.cpp)
+  install(TARGETS ${NAME} DESTINATION bin)
+
+else()
+  message("## Skipping '${NAME}': no OpenMP support found")
+endif()
+unset(NAME)
+

lud/lud_openmp/README.md

+README
+=======
+
+# 1. Code sample name
+lud_openmp
+
+# 2. Description of the code sample package
+This example demonstrates the use of OpenMP for LU decomposition (Doolittle algorithm).
+
+# 3. Release date
+19 August 2016
+
+# 4. Version history
+1.0
+
+# 6. Copyright / License of the code sample
+Apache Version 2.0
+
+# 5. Contributor (s) / Maintainer(s)
+Rafal Gandecki <rafal.gandecki@pwr.edu.pl>
+
+# 7. Language(s)
+C++ 11
+
+# 8. Parallelisation Implementation(s)
+OpenMP
+
+# 9. Level of the code sample complexity
+basic
+
+# 10. Instructions on how to compile the code
+Uses the CodeVault CMake infrastructure, see main README.md
+
+# 11. Instructions on how to run the code
+Just run compiled executable
+
+# 12. Sample input(s)
+1 argument:
+- matrix size
+
+# 13. Sample output(s)
+execution time of algorthims with and without OpenMP
+~                                                                                                                      
+~                                                                                                                      
+~                                                                                                                      
+~                                                                                                                      
+~                                                                                                                      
+~                                                                              

lud/lud_openmp/src/lud_openmp.cpp

+// =================================================================================================
+// This file is part of the CodeVault project. The project is licensed under Apache Version 2.0.
+// CodeVault is part of the EU-project PRACE-4IP (WP7.3.C).
+//
+// Author(s):
+//   Rafal Gandecki <rafal.gandecki@pwr.edu.pl>
+//
+// This example demonstrates the use of OpenMP for LU decomposition (Doolittle algorithm) and
+// compares execution time.
+// The example takes a single input argument, specifying the size of the matrices.
+//
+// See [http://www.openmp.org/] for the full OpenMP documentation.
+//
+// =================================================================================================
+
+#include <omp.h>
+#include <random>
+#include <iostream>
+
+void fill_random(float *A, const int &n, const int &m)
+{
+  std::mt19937 e(static_cast<unsigned int>(time(nullptr)));
+  std::uniform_real_distribution<float> f;
+  for(int i=0; i<n; ++i)
+  {
+    for(int j=0; j<m; ++j)
+    {
+      A[i*m+j] = f(e);
+    }
+  }
+}
+
+
+void lud(float *A, float *L, float *U, const int &n)
+{
+  for(int i=0;  i<n; i++)
+  {
+    for(int j=0; j<n; j++)
+    {
+      if(j>i)
+        U[j*n+i] = 0;
+      U[i*n+j] = A[i*n+j];
+      for(int k=0; k<i; k++)
+      {
+        U[i*n+j] -= U[k*n+j] * L[i*n+k];
+      }
+    }
+    for(int j=0; j<n; j++)
+    {
+      if(i>j)
+        L[j*n+i] = 0;
+      else if (j==i)
+        L[j*n+i] = 1;
+      else
+      {
+        L[j*n+i] = A[j*n+i] / U[i*n+i];
+        for(int k=0; k<i; k++)
+        {
+          L[j*n+i] -= ((U[k*n+i] * L[j*n+k]) / U[i*n+i]);
+        }
+      }
+    }
+  }
+}
+
+void lud_OpenMP(float *A, float *L, float *U, const int &n)
+{
+  int i, j, k;
+  #pragma omp parallel for shared(A, L, U, n) private(i, j, k)
+  for (i=0; i<n; i++)
+  {
+    for(j=0; j<n; j++)
+    {
+      if(j>i)
+        U[j*n+i] = 0;
+      U[i*n+j] = A[i*n+j];
+      for(k=0; k<i; k++)
+      {
+        U[i*n+j] -= U[k*n+j] * L[i*n+k];
+      }
+     }
+    for(j=0; j<n; j++)
+    {
+      if(i>j)
+        L[j*n+i] = 0;
+      else if (j==i)
+        L[j*n+i] = 1;
+      else
+      {
+        L[j*n+i] = A[j*n+i] / U[i*n+i];
+        for(k=0; k<i; k++)
+        {
+          L[j*n+i] -= ((U[k*n+i] * L[j*n+k]) / U[i*n+i]);
+        }
+      }
+    }
+  }
+}
+
+int main(int argc, char **argv)
+{
+  int n;
+  float *A, *L, *U;
+  if (argc != 2)
+  {
+    std::cout << "Usage: 1 argument: matrix size" << std::endl;
+    return 1;
+  }
+  else
+  {
+    n = atoi(argv[1]);
+  }
+
+  A = new float[n*n];
+  L = new float[n*n];
+  U = new float[n*n];
+
+  fill_random(A, n, n);
+
+  double dtime;
+  dtime = omp_get_wtime();
+  lud(A, L, U, n);
+  dtime = omp_get_wtime() - dtime;
+  std::cout << "Time without OpenMP: " << dtime << std::endl;
+
+  dtime = omp_get_wtime();
+  lud_OpenMP(A, L, U, n);
+  dtime = omp_get_wtime() - dtime;
+  std::cout << "Time with OpenMP: " << dtime << std::endl;
+
+  delete[] A;
+  delete[] L;
+  delete[] U;
+  return 0;
+}