Fix #1974: assertion when reserving an empty sparse matrix

2 files changed, 10 insertions, 1 deletions

diff --git a/Eigen/src/SparseCore/SparseMatrix.h b/Eigen/src/SparseCore/SparseMatrix.h
index 2218b220b..4e639d1f8 100644
--- a/Eigen/src/SparseCore/SparseMatrix.h
+++ b/Eigen/src/SparseCore/SparseMatrix.h
@@ -329,7 +329,8 @@ class SparseMatrix
           m_outerIndex[j] = newOuterIndex[j];
           m_innerNonZeros[j] = innerNNZ;
         }
-        m_outerIndex[m_outerSize] = m_outerIndex[m_outerSize-1] + m_innerNonZeros[m_outerSize-1] + reserveSizes[m_outerSize-1];
+        if(m_outerSize>0)
+          m_outerIndex[m_outerSize] = m_outerIndex[m_outerSize-1] + m_innerNonZeros[m_outerSize-1] + reserveSizes[m_outerSize-1];
         
         m_data.resize(m_outerIndex[m_outerSize]);
       }
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index 9e735b38b..5f8762172 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -662,6 +662,14 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
     iters[0] = IteratorType(m2,0);
     iters[1] = IteratorType(m2,m2.outerSize()-1);
   }
+
+  // test reserve with empty rows/columns
+  {
+    SparseMatrixType m1(0,cols);
+    m1.reserve(ArrayXi::Constant(m1.outerSize(),1));
+    SparseMatrixType m2(rows,0);
+    m2.reserve(ArrayXi::Constant(m2.outerSize(),1));
+  }
 }