// 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.
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// Author: sameeragarwal@google.com (Sameer Agarwal)
#include "ceres/block_random_access_crs_matrix.h"
#include <algorithm>
#include <set>
#include <utility>
#include <vector>
#include "ceres/compressed_row_sparse_matrix.h"
#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 {
BlockRandomAccessCRSMatrix::BlockRandomAccessCRSMatrix(
const vector<int>& blocks,
const set<pair<int, int> >& block_pairs)
: kMaxRowBlocks(10 * 1000 * 1000),
blocks_(blocks) {
CHECK_LT(blocks.size(), kMaxRowBlocks);
col_layout_.resize(blocks_.size(), 0);
row_strides_.resize(blocks_.size(), 0);
// Build the row/column layout vector and count the number of scalar
// rows/columns.
int num_cols = 0;
for (int i = 0; i < blocks_.size(); ++i) {
col_layout_[i] = num_cols;
num_cols += blocks_[i];
}
// Walk the sparsity pattern and count the number of non-zeros.
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(2) << "Matrix Size [" << num_cols
<< "," << num_cols
<< "] " << num_nonzeros;
crsm_.reset(new CompressedRowSparseMatrix(num_cols, num_cols, num_nonzeros));
int* rows = crsm_->mutable_rows();
int* cols = crsm_->mutable_cols();
double* values = crsm_->mutable_values();
// Iterate over the sparsity pattern and fill the scalar sparsity
// pattern of the underlying compressed sparse row matrix. Along the
// way also fill out the Layout object which will allow random
// access into the CRS Matrix.
set<pair<int, int> >::const_iterator it = block_pairs.begin();
vector<int> col_blocks;
int row_pos = 0;
rows[0] = 0;
while (it != block_pairs.end()) {
// Add entries to layout_ for all the blocks for this row.
col_blocks.clear();
const int row_block_id = it->first;
const int row_block_size = blocks_[row_block_id];
int num_cols = 0;
while ((it != block_pairs.end()) && (it->first == row_block_id)) {
layout_[IntPairToLong(it->first, it->second)] =
new CellInfo(values + num_cols);
col_blocks.push_back(it->second);
num_cols += blocks_[it->second];
++it;
};
// Count the number of non-zeros in the row block.
for (int j = 0; j < row_block_size; ++j) {
rows[row_pos + j + 1] = rows[row_pos + j] + num_cols;
}
// Fill out the sparsity pattern for each row.
int col_pos = 0;
for (int j = 0; j < col_blocks.size(); ++j) {
const int col_block_id = col_blocks[j];
const int col_block_size = blocks_[col_block_id];
for (int r = 0; r < row_block_size; ++r) {
const int column_block_begin = rows[row_pos + r] + col_pos;
for (int c = 0; c < col_block_size; ++c) {
cols[column_block_begin + c] = col_layout_[col_block_id] + c;
}
}
col_pos += col_block_size;
}
row_pos += row_block_size;
values += row_block_size * num_cols;
row_strides_[row_block_id] = num_cols;
}
}
// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
BlockRandomAccessCRSMatrix::~BlockRandomAccessCRSMatrix() {
// TODO(sameeragarwal) this should be rationalized going forward and
// perhaps moved into BlockRandomAccessMatrix.
for (LayoutType::iterator it = layout_.begin();
it != layout_.end();
++it) {
delete it->second;
}
}
CellInfo* BlockRandomAccessCRSMatrix::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;
}
*row = 0;
*col = 0;
*row_stride = blocks_[row_block_id];
*col_stride = row_strides_[row_block_id];
return it->second;
}
// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
void BlockRandomAccessCRSMatrix::SetZero() {
crsm_->SetZero();
}
} // namespace internal
} // namespace ceres