Added support and tests: row and column blocks for sparse matrix
transpose.

Change-Id: Ife641b08a9e86826478521a405f21ba60667f0e8

internal/ceres/compressed_row_sparse_matrix.cc

diff --git a/internal/ceres/compressed_row_sparse_matrix.cc b/internal/ceres/compressed_row_sparse_matrix.cc
index 34f31ab..bef98d6 100644
--- a/internal/ceres/compressed_row_sparse_matrix.cc
+++ b/internal/ceres/compressed_row_sparse_matrix.cc
@@ -377,6 +377,9 @@
   }
   transpose_rows[0] = 0;
 
+  *(transpose->mutable_row_blocks()) = col_blocks_;
+  *(transpose->mutable_col_blocks()) = row_blocks_;
+
   return transpose;
 }
 

internal/ceres/compressed_row_sparse_matrix_test.cc

diff --git a/internal/ceres/compressed_row_sparse_matrix_test.cc b/internal/ceres/compressed_row_sparse_matrix_test.cc
index ea737b8..999a661 100644
--- a/internal/ceres/compressed_row_sparse_matrix_test.cc
+++ b/internal/ceres/compressed_row_sparse_matrix_test.cc
@@ -338,10 +338,22 @@
   // 13  0 14 15  9  0
   //  0 16 17  0  0  0
 
+  // Block structure:
+  //  A  A  A  A  B  B
+  //  A  A  A  A  B  B
+  //  A  A  A  A  B  B
+  //  C  C  C  C  D  D
+  //  C  C  C  C  D  D
+  //  C  C  C  C  D  D
+
   CompressedRowSparseMatrix matrix(5, 6, 30);
   int* rows = matrix.mutable_rows();
   int* cols = matrix.mutable_cols();
   double* values = matrix.mutable_values();
+  matrix.mutable_row_blocks()->push_back(3);
+  matrix.mutable_row_blocks()->push_back(3);
+  matrix.mutable_col_blocks()->push_back(4);
+  matrix.mutable_col_blocks()->push_back(2);
 
   rows[0] = 0;
   cols[0] = 1;
@@ -376,6 +388,16 @@
 
   scoped_ptr<CompressedRowSparseMatrix> transpose(matrix.Transpose());
 
+  ASSERT_EQ(transpose->row_blocks().size(), matrix.col_blocks().size());
+  for (int i = 0; i < transpose->row_blocks().size(); ++i) {
+    EXPECT_EQ(transpose->row_blocks()[i], matrix.col_blocks()[i]);
+  }
+
+  ASSERT_EQ(transpose->col_blocks().size(), matrix.row_blocks().size());
+  for (int i = 0; i < transpose->col_blocks().size(); ++i) {
+    EXPECT_EQ(transpose->col_blocks()[i], matrix.row_blocks()[i]);
+  }
+
   Matrix dense_matrix;
   matrix.ToDenseMatrix(&dense_matrix);