1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 2015 Google Inc. All rights reserved.
3 // http://ceres-solver.org/
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6 // modification, are permitted provided that the following conditions are met:
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9 // this list of conditions and the following disclaimer.
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11 // this list of conditions and the following disclaimer in the documentation
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
31 // Utility routines for validating arrays.
33 // These are useful for detecting two common class of errors.
35 // 1. Uninitialized memory - where the user for some reason did not
36 // compute part of an array, but the code expects it.
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.
43 #ifndef CERES_INTERNAL_ARRAY_UTILS_H_
44 #define CERES_INTERNAL_ARRAY_UTILS_H_
47 #include "ceres/internal/port.h"
52 // Fill the array x with an impossible value that the user code is
53 // never expected to compute.
54 void InvalidateArray(int size, double* x);
56 // Check if all the entries of the array x are valid, i.e. all the
57 // values in the array should be finite and none of them should be
58 // equal to the "impossible" value used by InvalidateArray.
59 bool IsArrayValid(int size, const double* x);
61 // If the array contains an invalid value, return the index for it,
62 // otherwise return size.
63 int FindInvalidValue(const int size, const double* x);
65 // Utility routine to print an array of doubles to a string. If the
66 // array pointer is NULL, it is treated as an array of zeros.
67 void AppendArrayToString(const int size, const double* x, std::string* result);
69 // This routine takes an array of integer values, sorts and uniques
70 // them and then maps each value in the array to its position in the
71 // sorted+uniqued array. By doing this, if there are are k unique
72 // values in the array, each value is replaced by an integer in the
73 // range [0, k-1], while preserving their relative order.
82 void MapValuesToContiguousRange(int size, int* array);
84 } // namespace internal
87 #endif // CERES_INTERNAL_ARRAY_UTILS_H_