Add a Select expression in the Array module which mimics a coeff-wise ?: operator.

Example:
  mat = (mat.cwise().abs().cwise() < Ones()).select(0,mat);
replaces all small values by 0. (the scalar version is "s = abs(s)<1 ? 0 : s")

2 files changed, 17 insertions, 2 deletions

diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 4248ae523..e6af97bb3 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -539,6 +539,18 @@ template<typename Derived> class MatrixBase
     static const CwiseNullaryOp<ei_scalar_random_op<Scalar>,Derived> Random(int size);
     static const CwiseNullaryOp<ei_scalar_random_op<Scalar>,Derived> Random();
 
+    template<typename ThenDerived,typename ElseDerived>
+    const Select<Derived,ThenDerived,ElseDerived>
+    select(const MatrixBase<ThenDerived>& thenMatrix,
+           const MatrixBase<ElseDerived>& elseMatrix) const;
+   
+    template<typename ThenDerived>
+    inline const Select<Derived,ThenDerived, NestByValue<typename ThenDerived::ConstantReturnType> >
+    select(const MatrixBase<ThenDerived>& thenMatrix, typename ThenDerived::Scalar elseScalar) const;
+    
+    template<typename ElseDerived>
+    inline const Select<Derived, NestByValue<typename ElseDerived::ConstantReturnType>, ElseDerived >
+    select(typename ElseDerived::Scalar thenScalar, const MatrixBase<ElseDerived>& elseMatrix) const;
 
 /////////// LU module ///////////
 
diff --git a/Eigen/src/Core/util/ForwardDeclarations.h b/Eigen/src/Core/util/ForwardDeclarations.h
index 92852cbfa..8a8beb9b7 100644
--- a/Eigen/src/Core/util/ForwardDeclarations.h
+++ b/Eigen/src/Core/util/ForwardDeclarations.h
@@ -50,8 +50,6 @@ template<typename MatrixType, int PacketAccess = AsRequested> class Map;
 template<typename MatrixType, unsigned int Mode> class Part;
 template<typename MatrixType, unsigned int Mode> class Extract;
 template<typename ExpressionType> class Cwise;
-template<typename ExpressionType, int Direction> class PartialRedux;
-template<typename MatrixType, typename BinaryOp, int Direction> class PartialReduxExpr;
 template<typename ExpressionType> class WithFormat;
 
 template<typename Lhs, typename Rhs> struct ei_product_mode;
@@ -94,6 +92,11 @@ void ei_cache_friendly_product(
   bool _rhsRowMajor, const Scalar* _rhs, int _rhsStride,
   bool resRowMajor, Scalar* res, int resStride);
 
+// Array module
+template<typename ConditionMatrixType, typename ThenMatrixType, typename ElseMatrixType> class Select;
+template<typename MatrixType, typename BinaryOp, int Direction> class PartialReduxExpr;
+template<typename ExpressionType, int Direction> class PartialRedux;
+
 template<typename MatrixType> class LU;
 template<typename MatrixType> class QR;
 template<typename MatrixType> class SVD;