##// END OF EJS Templates
Adds methods to handle search of min/max values in structures that can contain NaN values...
Alexandre Leroux -
r567:36d29ea2f20f
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@@ -59,6 +59,58 struct SortUtils {
59 59
60 60 return sortedData;
61 61 }
62
63 /**
64 * Compares two values that can be NaN. This method is intended to be used as a compare function
65 * for searching min value by excluding NaN values.
66 *
67 * Examples of use:
68 * - f({1, 3, 2, 4, 5}) will return 1
69 * - f({NaN, 3, 2, 4, 5}) will return 2 (NaN is excluded)
70 * - f({NaN, NaN, 3, NaN, NaN}) will return 3 (NaN are excluded)
71 * - f({NaN, NaN, NaN, NaN, NaN}) will return NaN (no existing value)
72 *
73 * @param v1 first value
74 * @param v2 second value
75 * @return true if v1 < v2, false otherwise
76 * @sa std::min_element
77 */
78 template <typename T>
79 static bool minCompareWithNaN(const T &v1, const T &v2)
80 {
81 // Table used with NaN values:
82 // NaN < v2 -> false
83 // v1 < NaN -> true
84 // NaN < NaN -> false
85 // v1 < v2 -> v1 < v2
86 return std::isnan(v1) ? false : std::isnan(v2) || (v1 < v2);
87 }
88
89 /**
90 * Compares two values that can be NaN. This method is intended to be used as a compare function
91 * for searching max value by excluding NaN values.
92 *
93 * Examples of use:
94 * - f({1, 3, 2, 4, 5}) will return 5
95 * - f({1, 3, 2, 4, NaN}) will return 4 (NaN is excluded)
96 * - f({NaN, NaN, 3, NaN, NaN}) will return 3 (NaN are excluded)
97 * - f({NaN, NaN, NaN, NaN, NaN}) will return NaN (no existing value)
98 *
99 * @param v1 first value
100 * @param v2 second value
101 * @return true if v1 < v2, false otherwise
102 * @sa std::max_element
103 */
104 template <typename T>
105 static bool maxCompareWithNaN(const T &v1, const T &v2)
106 {
107 // Table used with NaN values:
108 // NaN < v2 -> true
109 // v1 < NaN -> false
110 // NaN < NaN -> false
111 // v1 < v2 -> v1 < v2
112 return std::isnan(v1) ? true : !std::isnan(v2) && (v1 < v2);
113 }
62 114 };
63 115
64 116 #endif // SCIQLOP_SORTUTILS_H
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