// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
// http://code.google.com/p/ceres-solver/
//
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// modification, are permitted provided that the following conditions are met:
//
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// 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.
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// Author: sameeragarwal@google.com (Sameer Agarwal)
#include "ceres/block_random_access_sparse_matrix.h"
#include <algorithm>
#include <set>
#include <utility>
#include <vector>
#include "ceres/internal/port.h"
#include "ceres/internal/scoped_ptr.h"
#include "ceres/mutex.h"
#include "ceres/triplet_sparse_matrix.h"
#include "ceres/types.h"
#include "glog/logging.h"
namespace ceres {
namespace internal {
BlockRandomAccessSparseMatrix::BlockRandomAccessSparseMatrix(
const vector<int>& blocks,
const set<pair<int, int> >& block_pairs)
: kMaxRowBlocks(10 * 1000 * 1000),
blocks_(blocks) {
CHECK_LT(blocks.size(), kMaxRowBlocks);
// Build the row/column layout vector and count the number of scalar
// rows/columns.
int num_cols = 0;
vector<int> col_layout;
for (int i = 0; i < blocks_.size(); ++i) {
col_layout.push_back(num_cols);
num_cols += blocks_[i];
}
// Count the number of scalar non-zero entries and build the layout
// object for looking into the values array of the
// TripletSparseMatrix.
int num_nonzeros = 0;
for (set<pair<int, int> >::const_iterator it = block_pairs.begin();
it != block_pairs.end();
++it) {
const int row_block_size = blocks_[it->first];
const int col_block_size = blocks_[it->second];
num_nonzeros += row_block_size * col_block_size;
}
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 (set<pair<int, int> >::const_iterator it = block_pairs.begin();
it != block_pairs.end();
++it) {
const int row_block_size = blocks_[it->first];
const int col_block_size = blocks_[it->second];
layout_[IntPairToLong(it->first, it->second)] =
new CellInfo(values + pos);
pos += row_block_size * col_block_size;
}
// Fill the sparsity pattern of the underlying matrix.
for (set<pair<int, int> >::const_iterator it = block_pairs.begin();
it != block_pairs.end();
++it) {
const int row_block_id = it->first;
const int col_block_id = it->second;
const int row_block_size = blocks_[row_block_id];
const int col_block_size = blocks_[col_block_id];
int pos =
layout_[IntPairToLong(row_block_id, col_block_id)]->values - values;
for (int r = 0; r < row_block_size; ++r) {
for (int c = 0; c < col_block_size; ++c, ++pos) {
rows[pos] = col_layout[row_block_id] + r;
cols[pos] = col_layout[col_block_id] + c;
values[pos] = 1.0;
DCHECK_LT(rows[pos], tsm_->num_rows());
DCHECK_LT(cols[pos], tsm_->num_rows());
}
}
}
}
// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
BlockRandomAccessSparseMatrix::~BlockRandomAccessSparseMatrix() {
for (LayoutType::iterator it = layout_.begin();
it != layout_.end();
++it) {
delete it->second;
}
}
CellInfo* BlockRandomAccessSparseMatrix::GetCell(int row_block_id,
int col_block_id,
int* row,
int* col,
int* row_stride,
int* col_stride) {
const LayoutType::iterator it =
layout_.find(IntPairToLong(row_block_id, col_block_id));
if (it == layout_.end()) {
return NULL;
}
// Each cell is stored contiguously as its own little dense matrix.
*row = 0;
*col = 0;
*row_stride = blocks_[row_block_id];
*col_stride = blocks_[col_block_id];
return it->second;
}
// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
void BlockRandomAccessSparseMatrix::SetZero() {
if (tsm_->num_nonzeros()) {
VectorRef(tsm_->mutable_values(),
tsm_->num_nonzeros()).setZero();
}
}
} // namespace internal
} // namespace ceres