Mercurial > octave-nkf

comparison liboctave/Array-f.cc @ 9922:3a8327d51ed4

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optimize issorted for doubles & floats
author Jaroslav Hajek <highegg@gmail.com>
date Sat, 05 Dec 2009 21:30:47 +0100
parents 56fbe170d354
children 1369f13ae6b2
comparison
equal deleted inserted replaced
9921:7c8392a034e6 9922:3a8327d51ed4
82 } 82 }
83 83
84 return result; 84 return result;
85 } 85 }
86 86
87 // The default solution using NaN-safe comparator is OK, but almost twice as
88 // slow than this code.
89 template <>
90 sortmode
91 Array<float>::is_sorted (sortmode mode) const
92 {
93 octave_idx_type n = numel ();
94
95 const float *el = data ();
96
97 if (n <= 1)
98 return mode ? mode : ASCENDING;
99
100 if (! mode)
101 {
102 // Auto-detect mode.
103 if (el[n-1] < el[0] || xisnan (el[0]))
104 mode = DESCENDING;
105 else
106 mode = ASCENDING;
107 }
108
109 if (mode == DESCENDING)
110 {
111 octave_idx_type j = 0;
112 float r;
113 // Sort out NaNs.
114 do
115 r = el[j++];
116 while (xisnan (r) && j < n);
117
118 // Orient the test so that NaN will not pass through.
119 for (; j < n; j++)
120 {
121 if (r >= el[j])
122 r = el[j];
123 else
124 {
125 mode = UNSORTED;
126 break;
127 }
128 }
129
130 }
131 else if (mode == ASCENDING)
132 {
133 // Sort out NaNs.
134 while (n > 0 && xisnan (el[n-1]))
135 n--;
136
137 if (n > 0)
138 {
139 // Orient the test so that NaN will not pass through.
140 float r = el[0];
141 for (octave_idx_type j = 1; j < n; j++)
142 {
143 if (r <= el[j])
144 r = el[j];
145 else
146 {
147 mode = UNSORTED;
148 break;
149 }
150 }
151 }
152 }
153
154 return mode;
155 }
156
87 INSTANTIATE_ARRAY_SORT (float); 157 INSTANTIATE_ARRAY_SORT (float);
88 158
89 INSTANTIATE_ARRAY (float, OCTAVE_API); 159 INSTANTIATE_ARRAY (float, OCTAVE_API);
90 160
91 #include "Array2.h" 161 #include "Array2.h"