dither.cpp
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34 
35 // Original version: Kevin Watts <watts@willowgarage.com>
36 
37 #include <control_toolbox/dither.h>
38 
39 namespace control_toolbox {
40 
41 Dither::Dither() : amplitude_(0), has_saved_value_(false)
42 {
43 
44 }
45 
47 {
48 }
49 
51 {
52  if (has_saved_value_)
53  {
54  has_saved_value_ = false;
55  return saved_value_;
56  }
57 
58  // Generates gaussian random noise using the polar method.
59  double v1, v2, r;
60  for (int i = 0; i < 100; ++i)
61  {
62  v1 = 2.0 * erand48(seed_) - 1.0; // [-1, 1]
63  v2 = 2.0 * erand48(seed_) - 1.0; // [-1, 1]
64  r = v1*v1 + v2*v2;
65  if (r <= 1.0)
66  break;
67  }
68  if (r > 1.0)
69  r = 1.0;
70 
71  double f = sqrt(-2.0 * log(r) / r);
72  double current = amplitude_ * f * v1;
73  saved_value_ = amplitude_ * f * v2;
74  has_saved_value_ = true;
75 
76  return current;
77 }
78 
79 }
~Dither()
Destructor.
Definition: dither.cpp:46
f
double update()
Get next Gaussian white noise point. Called in RT loop.
Definition: dither.cpp:50
unsigned short seed_[3]
Definition: dither.h:108


control_toolbox
Author(s): Melonee Wise, Sachin Chitta, John Hsu
autogenerated on Mon Jun 10 2019 12:56:31