// 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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// Author: sameeragarwal@google.com (Sameer Agarwal)
//
// Utility routines for ResidualBlock evaluation.
//
// These are useful for detecting two common class of errors.
//
// 1. Uninitialized memory - where the user for some reason did not
// compute part of a cost/residual/jacobian.
//
// 2. Numerical failure while computing the cost/residual/jacobian,
// e.g. NaN, infinities etc. This is particularly useful since the
// automatic differentiation code does computations that are not
// evident to the user and can silently generate hard to debug errors.

#ifndef CERES_INTERNAL_RESIDUAL_BLOCK_UTILS_H_
#define CERES_INTERNAL_RESIDUAL_BLOCK_UTILS_H_

#include <string>
#include "ceres/internal/port.h"

namespace ceres {
namespace internal {

class ResidualBlock;

// Fill the array x with an impossible value that the user code is
// never expected to compute.
void InvalidateArray(int size, double* x);

// Check if all the entries of the array x are valid, i.e. all the
// values in the array should be finite and none of them should be
// equal to the "impossible" value used by InvalidateArray.
bool IsArrayValid(int size, const double* x);

// Invalidate cost, resdual and jacobian arrays (if not NULL).
void InvalidateEvaluation(const ResidualBlock& block,
                          double* cost,
                          double* residuals,
                          double** jacobians);

// Check if any of the arrays cost, residuals or jacobians contains an
// NaN, return true if it does.
bool IsEvaluationValid(const ResidualBlock& block,
                       double const* const* parameters,
                       double* cost,
                       double* residuals,
                       double** jacobians);

// Create a string representation of the Residual block containing the
// value of the parameters, residuals and jacobians if present.
// Useful for debugging output.
string EvaluationToString(const ResidualBlock& block,
                          double const* const* parameters,
                          double* cost,
                          double* residuals,
                          double** jacobians);

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_RESIDUAL_BLOCK_UTILS_H_