// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

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// Author: sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_INTERNAL_DETECT_STRUCTURE_H_

#define CERES_INTERNAL_DETECT_STRUCTURE_H_

#include "ceres/block_structure.h"

namespace ceres {

namespace internal {

// Detect static blocks in the problem sparsity. For rows containing

// e_blocks, we are interested in detecting if the size of the row

// blocks, e_blocks and the f_blocks remain constant. If they do, then

// we can use template specialization to improve the performance of

// the block level linear algebra operations used by the

// SchurEliminator.

//

// If a block size is not constant, we return Eigen::Dynamic as the

// value. This just means that the eliminator uses dynamically sized

// linear algebra operations rather than static operations whose size

// is known as compile time.

//

// For more details about e_blocks and f_blocks, see

// schur_eliminator.h. This information is used to initialized an

// appropriate template specialization of SchurEliminator.

//

// Note: The structure of rows without any e-blocks has no effect on

// the values returned by this function. It is entirely possible that

// the f_block_size and row_blocks_size is not constant in such rows.

void DetectStructure(const CompressedRowBlockStructure& bs,

                     const int num_eliminate_blocks,

                     int* row_block_size,

                     int* e_block_size,

                     int* f_block_size);

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_DETECT_STRUCTURE_H_