imag.cpp

   1 /* Returns the coefficient of the imaginary part of complex z
   2
   3         z               imag(z)
   4         -               -------
   5
   6         a + i b         b
   7
   8         exp(i a)        sin(a)
   9 */
  10
  11 #include "stdafx.h"
  12 #include "defs.h"
  13
  14 void
  15 eval_imag(void)
  16 {
  17         push(cadr(p1));
  18         eval();
  19         imag();
  20 }
  21
  22 void
  23 imag(void)
  24 {
  25         save();
  26         rect();
  27         p1 = pop();
  28         push(p1);
  29         push(p1);
  30         conjugate();
  31         subtract();
  32         push_integer(2);
  33         divide();
  34         push(imaginaryunit);
  35         divide();
  36         restore();
  37 }
  38
  39 #if SELFTEST
  40
  41 static char *s[] = {
  42
  43         "imag(a+i*b)",
  44         "b",
  45
  46         "imag(1+exp(i*pi/3))",
  47         "1/2*3^(1/2)",
  48
  49         "imag(i)",
  50         "1",
  51
  52         "imag((-1)^(1/3))",
  53         "1/2*3^(1/2)",
  54
  55         "imag(-i)",
  56         "-1",
  57 };
  58
  59 void
  60 test_imag(void)
  61 {
  62         test(__FILE__, s, sizeof s / sizeof (char *));
  63 }
  64
  65 #endif