diff --git a/Eigen/Core b/Eigen/Core
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -324,19 +324,19 @@ using std::ptrdiff_t;
#include "src/Core/IO.h"
#include "src/Core/Swap.h"
#include "src/Core/CommaInitializer.h"
#include "src/Core/Flagged.h"
#include "src/Core/ProductBase.h"
#include "src/Core/GeneralProduct.h"
#include "src/Core/TriangularMatrix.h"
#include "src/Core/SelfAdjointView.h"
+#include "src/Core/products/GeneralBlockPanelKernel.h"
#include "src/Core/products/Parallelizer.h"
#include "src/Core/products/CoeffBasedProduct.h"
-#include "src/Core/products/GeneralBlockPanelKernel.h"
#include "src/Core/products/GeneralMatrixVector.h"
#include "src/Core/products/GeneralMatrixMatrix.h"
#include "src/Core/SolveTriangular.h"
#include "src/Core/products/GeneralMatrixMatrixTriangular.h"
#include "src/Core/products/SelfadjointMatrixVector.h"
#include "src/Core/products/SelfadjointMatrixMatrix.h"
#include "src/Core/products/SelfadjointProduct.h"
#include "src/Core/products/SelfadjointRank2Update.h"
diff --git a/Eigen/src/Core/products/GeneralBlockPanelKernel.h b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
--- a/Eigen/src/Core/products/GeneralBlockPanelKernel.h
+++ b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
@@ -21,17 +21,17 @@
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see .
#ifndef EIGEN_GENERAL_BLOCK_PANEL_H
#define EIGEN_GENERAL_BLOCK_PANEL_H
namespace Eigen {
-
+
namespace internal {
template
class gebp_traits;
/** \internal \returns b if a<=0, and returns a otherwise. */
inline std::ptrdiff_t manage_caching_sizes_helper(std::ptrdiff_t a, std::ptrdiff_t b)
@@ -39,18 +39,17 @@ inline std::ptrdiff_t manage_caching_siz
return a<=0 ? b : a;
}
/** \internal */
inline void manage_caching_sizes(Action action, std::ptrdiff_t* l1=0, std::ptrdiff_t* l2=0)
{
static std::ptrdiff_t m_l1CacheSize = 0;
static std::ptrdiff_t m_l2CacheSize = 0;
- #pragma omp threadprivate(m_l1CacheSize,m_l2CacheSize)
- if(m_l1CacheSize==0)
+ if(m_l2CacheSize==0)
{
m_l1CacheSize = manage_caching_sizes_helper(queryL1CacheSize(),8 * 1024);
m_l2CacheSize = manage_caching_sizes_helper(queryTopLevelCacheSize(),1*1024*1024);
}
if(action==SetAction)
{
// set the cpu cache size and cache all block sizes from a global cache size in byte
diff --git a/Eigen/src/Core/products/Parallelizer.h b/Eigen/src/Core/products/Parallelizer.h
--- a/Eigen/src/Core/products/Parallelizer.h
+++ b/Eigen/src/Core/products/Parallelizer.h
@@ -52,32 +52,45 @@ inline void manage_multi_threading(Actio
#endif
}
else
{
eigen_internal_assert(false);
}
}
+}
+
+/** Must be call first when calling Eigen from multiple threads */
+inline void initParallel()
+{
+ int nbt;
+ internal::manage_multi_threading(GetAction, &nbt);
+ std::ptrdiff_t l1, l2;
+ internal::manage_caching_sizes(GetAction, &l1, &l2);
+}
+
/** \returns the max number of threads reserved for Eigen
* \sa setNbThreads */
inline int nbThreads()
{
int ret;
- manage_multi_threading(GetAction, &ret);
+ internal::manage_multi_threading(GetAction, &ret);
return ret;
}
/** Sets the max number of threads reserved for Eigen
* \sa nbThreads */
inline void setNbThreads(int v)
{
- manage_multi_threading(SetAction, &v);
+ internal::manage_multi_threading(SetAction, &v);
}
+namespace internal {
+
template struct GemmParallelInfo
{
GemmParallelInfo() : sync(-1), users(0), rhs_start(0), rhs_length(0) {}
int volatile sync;
int volatile users;
Index rhs_start;
@@ -116,16 +129,17 @@ void parallelize_gemm(const Functor& fun
Index max_threads = std::max(1,size / 32);
// 3 - compute the number of threads we are going to use
Index threads = std::min(nbThreads(), max_threads);
if(threads==1)
return func(0,rows, 0,cols);
+ Eigen::initParallel();
func.initParallelSession();
if(transpose)
std::swap(rows,cols);
Index blockCols = (cols / threads) & ~Index(0x3);
Index blockRows = (rows / threads) & ~Index(0x7);
diff --git a/doc/TopicMultithreading.dox b/doc/TopicMultithreading.dox
new file mode 100644
--- /dev/null
+++ b/doc/TopicMultithreading.dox
@@ -0,0 +1,46 @@
+namespace Eigen {
+
+/** \page TopicMultiThreading Eigen and multi-threading
+
+\section TopicMultiThreading_MakingEigenMT Make Eigen run in parallel
+
+Some Eigen's algorithms can exploit the multiple cores present in your hardware. To this end, it is enough to enable OpenMP on your compiler, for instance:
+ * GCC: \c -fopenmp
+ * ICC: \c -openmp
+ * MSVC: check the respective option in the build properties.
+You can control the number of thread that will be used using either the OpenMP API or Eiegn's API using the following priority:
+\code
+ OMP_NUM_THREADS=n ./my_program
+ omp_set_num_threads(n);
+ Eigen::setNbThreads(n);
+\endcode
+Unless setNbThreads has been called, Eigen uses the number of threads specified by OpenMP. You can restore this bahavior by calling \code setNbThreads(0); \endcode
+You can query the number of threads that will be used with:
+\code
+n = Eigen::nbThreads(n);
+\endcode
+You can disable Eigen's multi threading at compile time by defining the EIGEN_DONT_PARALLELIZE preprocessor token.
+
+Currently, the following algorithms can make use of multi-threading:
+ * general matrix - matrix products
+ * PartialPivLU
+
+\section TopicMultiThreading_UsingEigenWithMT Using Eigen in a multi-threaded application
+
+In the case your own application is multithreaded, and multiple threads make calls to Eigen, then you have to initialize Eigen by calling the following routine \b before creating the threads:
+\code
+#include
+
+int main(int argc, char** argv)
+{
+ Eigen::initParallel();
+
+ ...
+}
+\endcode
+
+In the case your application is parallelized with OpenMP, you might want to disable Eigen's own parallization as detailed in the previous section.
+
+*/
+
+}