[mlpack-git] master: Workaround for OpenMP 2.0 (based on dt_utils.cpp) (b92d465)

[gitdub at mlpack.org]

Repository : https://github.com/mlpack/mlpack
On branch  : master
Link       : https://github.com/mlpack/mlpack/compare/34cf8d94f79c9a72ff4199676033b060cd039fcd...425324bf7fb7c86c85d10a909d8a59d4f69b7164

>---------------------------------------------------------------

commit b92d46527c5d8b1487e4aa4810359292292107f1
Author: Yannis Mentekidis <mentekid at gmail.com>
Date:   Fri Jul 8 13:14:54 2016 +0100

    Workaround for OpenMP 2.0 (based on dt_utils.cpp)


>---------------------------------------------------------------

b92d46527c5d8b1487e4aa4810359292292107f1
 CMakeLists.txt                             |  2 +-
 src/mlpack/methods/lsh/lsh_search_impl.hpp | 22 +++++++++++++++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2f91fb6..02e9803 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -236,7 +236,7 @@ add_definitions(-DBOOST_TEST_DYN_LINK)
 # This way we can skip calls to functions defined in omp.h with code like:
 # if (HAS_OPENMP == 1) { openMP code here }
 # If OpenMP is found, define HAS_OPENMP to be 1. Otherwise define it to be 0.
-find_package(OpenMP 3.0.0)
+find_package(OpenMP)
 if (OPENMP_FOUND)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
diff --git a/src/mlpack/methods/lsh/lsh_search_impl.hpp b/src/mlpack/methods/lsh/lsh_search_impl.hpp
index c37aed9..066d5c0 100644
--- a/src/mlpack/methods/lsh/lsh_search_impl.hpp
+++ b/src/mlpack/methods/lsh/lsh_search_impl.hpp
@@ -825,10 +825,17 @@ void LSHSearch<SortPolicy>::Search(const arma::mat& querySet,
   #pragma omp parallel for \
     shared(avgIndicesReturned, resultingNeighbors, distances) \
     schedule(dynamic)
-  // Go through every query point.
-  for (size_t i = 0; i < querySet.n_cols; i++)
+#ifdef _WIN32
+  // Tiny workaround: Visual Studio only implements OpenMP 2.0, which doesn't
+  // support unsigned loop variables. If we're building for Visual Studio, use
+  // the intmax_t type instead.
+  intmax_t querySetSize = (intmax_t) querySet.n_cols;
+  for (intmax_t i = 0; i < querySetSize; ++i)
+#else
+  for (size_t i = 0; i < querySet.n_cols; ++i)
+#endif
   {
-
+    // Go through every query point.
     // Hash every query into every hash table and eventually into the
     // 'secondHashTable' to obtain the neighbor candidates.
     arma::uvec refIndices;
@@ -893,6 +900,15 @@ Search(const size_t k,
   #pragma omp parallel for \
     shared(avgIndicesReturned, resultingNeighbors, distances) \
     schedule(dynamic)
+#ifdef _WIN32
+  // Tiny workaround: Visual Studio only implements OpenMP 2.0, which doesn't
+  // support unsigned loop variables. If we're building for Visual Studio, use
+  // the intmax_t type instead.
+  intmax_t referenceSetSize = (intmax_t) referenceSet->n_cols;
+  for (intmax_t i = 0; i < referenceSetSize; ++i)
+#else
+  for (size_t i = 0; i < referenceSet->n_cols; ++i)
+#endif
   // Go through every query point. Use long int because some compilers complain
   // for openMP unsigned index variables.
   for (size_t i = 0; i < referenceSet->n_cols; i++)