From 0ad7a644df5c71b9a75c0300210ce17985b88044 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 1 Jul 2014 11:49:46 +0200
Subject: [PATCH] Implement nonZeros() for Transpose<sparse>

---
 Eigen/src/SparseCore/SparseTranspose.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Eigen/src/SparseCore/SparseTranspose.h b/Eigen/src/SparseCore/SparseTranspose.h
index b20843dd3..f5eff6133 100644
--- a/Eigen/src/SparseCore/SparseTranspose.h
+++ b/Eigen/src/SparseCore/SparseTranspose.h
@@ -61,6 +61,17 @@ template<typename MatrixType> class TransposeImpl<MatrixType,Sparse>::ReverseInn
 
 #else // EIGEN_TEST_EVALUATORS
 
+// Implement nonZeros() for transpose. I'm not sure that's the best approach for that.
+// Perhaps it should be implemented in Transpose<> itself.
+template<typename MatrixType> class TransposeImpl<MatrixType,Sparse>
+  : public SparseMatrixBase<Transpose<MatrixType> >
+{
+  protected:
+    typedef SparseMatrixBase<Transpose<MatrixType> > Base;
+  public:
+    inline typename MatrixType::Index nonZeros() const { return Base::derived().nestedExpression().nonZeros(); }
+};
+
 namespace internal {
   
 template<typename ArgType>