From 3eb5253ca1352391f4ea31c4a2dd06c34c4a33e7 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 2 Sep 2014 14:41:14 +0200
Subject: [PATCH] Optimization: "matrix<complex> * real" did not call the
 special path and the real was converted to a complex. Add respective unit
 test to avoid future regression.

---
 Eigen/src/Core/MatrixBase.h     |  1 +
 Eigen/src/Core/util/XprHelper.h | 10 +++++++++-
 test/linearstructure.cpp        | 26 ++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index f5987d194..3cb5e04fd 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -81,6 +81,7 @@ template<typename Derived> class MatrixBase
     using Base::operator-=;
     using Base::operator*=;
     using Base::operator/=;
+    using Base::operator*;
 
     typedef typename Base::CoeffReturnType CoeffReturnType;
     typedef typename Base::ConstTransposeReturnType ConstTransposeReturnType;
diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h
index 1b3e122e1..7c77b2263 100644
--- a/Eigen/src/Core/util/XprHelper.h
+++ b/Eigen/src/Core/util/XprHelper.h
@@ -383,13 +383,21 @@ struct special_scalar_op_base<Derived,Scalar,OtherScalar,true>  : public DenseCo
   const CwiseUnaryOp<scalar_multiple2_op<Scalar,OtherScalar>, Derived>
   operator*(const OtherScalar& scalar) const
   {
+#ifdef EIGEN_SPECIAL_SCALAR_MULTIPLE_PLUGIN
+    EIGEN_SPECIAL_SCALAR_MULTIPLE_PLUGIN
+#endif
     return CwiseUnaryOp<scalar_multiple2_op<Scalar,OtherScalar>, Derived>
       (*static_cast<const Derived*>(this), scalar_multiple2_op<Scalar,OtherScalar>(scalar));
   }
 
   inline friend const CwiseUnaryOp<scalar_multiple2_op<Scalar,OtherScalar>, Derived>
   operator*(const OtherScalar& scalar, const Derived& matrix)
-  { return static_cast<const special_scalar_op_base&>(matrix).operator*(scalar); }
+  {
+#ifdef EIGEN_SPECIAL_SCALAR_MULTIPLE_PLUGIN
+    EIGEN_SPECIAL_SCALAR_MULTIPLE_PLUGIN
+#endif
+    return static_cast<const special_scalar_op_base&>(matrix).operator*(scalar);
+  }
 };
 
 template<typename XprType, typename CastType> struct cast_return_type
diff --git a/test/linearstructure.cpp b/test/linearstructure.cpp
index 618984d5c..b627915ce 100644
--- a/test/linearstructure.cpp
+++ b/test/linearstructure.cpp
@@ -2,11 +2,16 @@
 // for linear algebra.
 //
 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
+// Copyright (C) 2014 Gael Guennebaud <gael.guennebaud@inria.fr>
 //
 // This Source Code Form is subject to the terms of the Mozilla
 // Public License v. 2.0. If a copy of the MPL was not distributed
 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+static bool g_called;
+
+#define EIGEN_SPECIAL_SCALAR_MULTIPLE_PLUGIN { g_called = true; }
+
 #include "main.h"
 
 template<typename MatrixType> void linearStructure(const MatrixType& m)
@@ -68,6 +73,24 @@ template<typename MatrixType> void linearStructure(const MatrixType& m)
   VERIFY_IS_APPROX(m1.block(0,0,rows,cols) * s1, m1 * s1);
 }
 
+// Make sure that complex * real and real * complex are properly optimized
+template<typename MatrixType> void real_complex(DenseIndex rows = MatrixType::RowsAtCompileTime, DenseIndex cols = MatrixType::ColsAtCompileTime)
+{
+  typedef typename MatrixType::Scalar Scalar;
+  typedef typename MatrixType::RealScalar RealScalar;
+  
+  RealScalar s = internal::random<RealScalar>();
+  MatrixType m1 = MatrixType::Random(rows, cols);
+  
+  g_called = false;
+  VERIFY_IS_APPROX(s*m1, Scalar(s)*m1);
+  VERIFY(g_called && "real * matrix<complex> not properly optimized");
+  
+  g_called = false;
+  VERIFY_IS_APPROX(m1*s, m1*Scalar(s));
+  VERIFY(g_called && "matrix<complex> * real not properly optimized");
+}
+
 void test_linearstructure()
 {
   for(int i = 0; i < g_repeat; i++) {
@@ -80,5 +103,8 @@ void test_linearstructure()
     CALL_SUBTEST_7( linearStructure(MatrixXi (internal::random<int>(1,EIGEN_TEST_MAX_SIZE), internal::random<int>(1,EIGEN_TEST_MAX_SIZE))) );
     CALL_SUBTEST_8( linearStructure(MatrixXcd(internal::random<int>(1,EIGEN_TEST_MAX_SIZE/2), internal::random<int>(1,EIGEN_TEST_MAX_SIZE/2))) );
     CALL_SUBTEST_9( linearStructure(ArrayXXf (internal::random<int>(1,EIGEN_TEST_MAX_SIZE), internal::random<int>(1,EIGEN_TEST_MAX_SIZE))) );
+    
+    CALL_SUBTEST_10( real_complex<Matrix4cd>() );
+    CALL_SUBTEST_10( real_complex<MatrixXcf>(10,10) );
   }
 }