Changeset 388 for cpp

Timestamp:

05/24/15 21:01:18 (10 years ago)

Author:

Maciej Komosinski

Message:

A local PRBS-7 implementation so that this file does not depend on external random number generators

File:

• cpp/frams/model/similarity/SVD/lapack.cpp (modified) (4 diffs)

cpp/frams/model/similarity/SVD/lapack.cpp

@@ -47 +47 @@
  * AutoBuffer from https://github.com/Itseez/opencv/blob/master/modules/core/include/opencv2/core/utility.hpp
  * VBLAS, JacobiSVDImpl_ from https://github.com/Itseez/opencv/blob/master/modules/core/src/lapack.cpp
- * changes:
- * - "RNG rng(0x12345678)" replaced with "srand(time(NULL))"
- * - "rng.next()" replaced with "rand()"
- * MK, 04.2015:
- * - commented out "srand(time(NULL))" - this line would affect everything else that uses the standard global r.n.g., and would introduce uncontrolled indeterminism
+ * changes MK, May 2015:
+ * - "RNG rng(0x12345678)" and "rng.next()" replaced with a local PRBS-7 implementation so that this file does not depend on external random number generators.
  */
 #include <cstdlib>
@@ -58 +55 @@
 #include <limits>
 #include <cfloat>
-#include <assert.h>
+//#include <assert.h>
+#include <math.h> //hypot(), embarcadero
+#include <stdint.h> //uint8_t
 #include "lapack.h"
-#include <stdlib.h> //rand(), embarcadero
-#include <math.h> //hypot(), embarcadero
-
-typedef unsigned char uchar;
+
 
 #if defined _M_IX86 && defined _MSC_VER && _MSC_VER < 1700
@@ -376 +372 @@
         return;
 
-    //srand(time(NULL));
-    for (i = 0; i < n1; i++)
+        uint8_t rndstate = 0x02; //PRBS-7 from http://en.wikipedia.org/wiki/Pseudorandom_binary_sequence
+        for (i = 0; i < n1; i++)
     {
         sd = i < n ? W[i] : 0;
@@ -389 +385 @@
             for (k = 0; k < m; k++)
             {
-                _Tp val = (rand() & 256) != 0 ? val0 : -val0;
+                                int rndbit = (((rndstate >> 6) ^ (rndstate >> 5)) & 1);
+                                rndstate = ((rndstate << 1) | rndbit) & 0x7f;
+                                _Tp val = rndbit == 0 ? val0 : -val0;
                 At[i * astep + k] = val;
             }