In SparseMatrix.h, function reserveInnerVectors90, line 294, change:

        Index count = 0;
        for(Index j=0; j<m_outerSize; ++j)
        {
          newOuterIndex[j] = count;
          count += reserveSizes[j] + (m_outerIndex[j+1]-m_outerIndex[j]);
          totalReserveSize += reserveSizes[j];
        }
        m_data.reserve(totalReserveSize);

to:

        for(Index j=0; j<m_outerSize; ++j)
        {
          newOuterIndex[j] = totalReserveSize;
          totalReserveSize += reserveSizes[j];
        }
        m_data.reserve(totalReserveSize);

Please enhance this function to support rowmajor matrices as well.