1// Ceres Solver - A fast non-linear least squares minimizer
2// Copyright 2012 Google Inc. All rights reserved.
3// http://code.google.com/p/ceres-solver/
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are met:
7//
8// * Redistributions of source code must retain the above copyright notice,
9//   this list of conditions and the following disclaimer.
10// * Redistributions in binary form must reproduce the above copyright notice,
11//   this list of conditions and the following disclaimer in the documentation
12//   and/or other materials provided with the distribution.
13// * Neither the name of Google Inc. nor the names of its contributors may be
14//   used to endorse or promote products derived from this software without
15//   specific prior written permission.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27// POSSIBILITY OF SUCH DAMAGE.
28//
29// Author: sameeragarwal@google.com (Sameer Agarwal)
30//
31// Utility routines for validating arrays.
32//
33// These are useful for detecting two common class of errors.
34//
35// 1. Uninitialized memory - where the user for some reason did not
36// compute part of an array, but the code expects it.
37//
38// 2. Numerical failure while computing the cost/residual/jacobian,
39// e.g. NaN, infinities etc. This is particularly useful since the
40// automatic differentiation code does computations that are not
41// evident to the user and can silently generate hard to debug errors.
42
43#ifndef CERES_INTERNAL_ARRAY_UTILS_H_
44#define CERES_INTERNAL_ARRAY_UTILS_H_
45
46#include "ceres/internal/port.h"
47
48namespace ceres {
49namespace internal {
50
51// Fill the array x with an impossible value that the user code is
52// never expected to compute.
53void InvalidateArray(int size, double* x);
54
55// Check if all the entries of the array x are valid, i.e. all the
56// values in the array should be finite and none of them should be
57// equal to the "impossible" value used by InvalidateArray.
58bool IsArrayValid(int size, const double* x);
59
60// If the array contains an invalid value, return the index for it,
61// otherwise return size.
62int FindInvalidValue(const int size, const double* x);
63
64// Utility routine to print an array of doubles to a string. If the
65// array pointer is NULL, it is treated as an array of zeros.
66void AppendArrayToString(const int size, const double* x, string* result);
67
68extern const double kImpossibleValue;
69
70// This routine takes an array of integer values, sorts and uniques
71// them and then maps each value in the array to its position in the
72// sorted+uniqued array. By doing this, if there are are k unique
73// values in the array, each value is replaced by an integer in the
74// range [0, k-1], while preserving their relative order.
75//
76// For example
77//
78// [1 0 3 5 0 1 5]
79//
80// gets mapped to
81//
82// [1 0 2 3 0 1 3]
83void MapValuesToContiguousRange(int size, int* array);
84
85}  // namespace internal
86}  // namespace ceres
87
88#endif  // CERES_INTERNAL_ARRAY_UTILS_H_
89