Add BlockRandomAccessDiagonalMatrix.
This class is used in the SchurJacobiPreconditioner for
storing the preconditioner matrix. Using it speeds up
the computation of the preconditioner by ~15% due to
the elimination of a hash table lookup.
Change-Id: Iba2b34aad0d9eb9bcb7f6e6fad16aa416aac0d2a
diff --git a/internal/ceres/block_random_access_diagonal_matrix.cc b/internal/ceres/block_random_access_diagonal_matrix.cc
new file mode 100644
index 0000000..d8bf4ef
--- /dev/null
+++ b/internal/ceres/block_random_access_diagonal_matrix.cc
@@ -0,0 +1,120 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2013 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: sameeragarwal@google.com (Sameer Agarwal)
+
+#include "ceres/block_random_access_diagonal_matrix.h"
+
+#include <algorithm>
+#include <set>
+#include <utility>
+#include <vector>
+#include "ceres/internal/port.h"
+#include "ceres/internal/scoped_ptr.h"
+#include "ceres/triplet_sparse_matrix.h"
+#include "ceres/types.h"
+#include "ceres/stl_util.h"
+#include "glog/logging.h"
+
+namespace ceres {
+namespace internal {
+
+BlockRandomAccessDiagonalMatrix::BlockRandomAccessDiagonalMatrix(
+ const vector<int>& blocks)
+ : blocks_(blocks) {
+ // Build the row/column layout vector and count the number of scalar
+ // rows/columns.
+ int num_cols = 0;
+ int num_nonzeros = 0;
+ vector<int> col_layout;
+ for (int i = 0; i < blocks_.size(); ++i) {
+ col_layout.push_back(num_cols);
+ num_cols += blocks_[i];
+ num_nonzeros += blocks_[i] * blocks_[i];
+ }
+
+ VLOG(1) << "Matrix Size [" << num_cols
+ << "," << num_cols
+ << "] " << num_nonzeros;
+
+ tsm_.reset(new TripletSparseMatrix(num_cols, num_cols, num_nonzeros));
+ tsm_->set_num_nonzeros(num_nonzeros);
+ int* rows = tsm_->mutable_rows();
+ int* cols = tsm_->mutable_cols();
+ double* values = tsm_->mutable_values();
+
+ int pos = 0;
+ for (int i = 0; i < blocks_.size(); ++i) {
+ const int block_size = blocks_[i];
+ layout_.push_back(new CellInfo(values + pos));
+ const int block_begin = col_layout[i];
+ for (int r = 0; r < block_size; ++r) {
+ for (int c = 0; c < block_size; ++c, ++pos) {
+ rows[pos] = block_begin + r;
+ cols[pos] = block_begin + c;
+ }
+ }
+ }
+}
+
+// Assume that the user does not hold any locks on any cell blocks
+// when they are calling SetZero.
+BlockRandomAccessDiagonalMatrix::~BlockRandomAccessDiagonalMatrix() {
+ STLDeleteContainerPointers(layout_.begin(), layout_.end());
+}
+
+CellInfo* BlockRandomAccessDiagonalMatrix::GetCell(int row_block_id,
+ int col_block_id,
+ int* row,
+ int* col,
+ int* row_stride,
+ int* col_stride) {
+ if (row_block_id != col_block_id) {
+ return NULL;
+ }
+ const int stride = blocks_[row_block_id];
+
+ // Each cell is stored contiguously as its own little dense matrix.
+ *row = 0;
+ *col = 0;
+ *row_stride = stride;
+ *col_stride = stride;
+ return layout_[row_block_id];
+}
+
+// Assume that the user does not hold any locks on any cell blocks
+// when they are calling SetZero.
+void BlockRandomAccessDiagonalMatrix::SetZero() {
+ if (tsm_->num_nonzeros()) {
+ VectorRef(tsm_->mutable_values(),
+ tsm_->num_nonzeros()).setZero();
+ }
+}
+
+} // namespace internal
+} // namespace ceres
