GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73679
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xtan.c
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1 
2 #include <stdlib.h>
3 #include <math.h>
4 
5 #include <grass/gis.h>
6 #include <grass/raster.h>
7 #include <grass/calc.h>
8 
9 /**********************************************************************
10 tan(x)
11 
12  if floating point exception occurs during the evaluation of tan(x)
13  the result is NULL
14 
15  note: x is in degrees.
16 **********************************************************************/
17 
18 #define DEGREES_TO_RADIANS (M_PI / 180.0)
19 
20 int f_tan(int argc, const int *argt, void **args)
21 {
22  DCELL *res = args[0];
23  DCELL *arg1 = args[1];
24  int i;
25 
26  if (argc < 1)
27  return E_ARG_LO;
28  if (argc > 1)
29  return E_ARG_HI;
30 
31  if (argt[0] != DCELL_TYPE)
32  return E_RES_TYPE;
33 
34  if (argt[1] != DCELL_TYPE)
35  return E_ARG_TYPE;
36 
37  for (i = 0; i < columns; i++)
38  if (IS_NULL_D(&arg1[i]))
39  SET_NULL_D(&res[i]);
40  else {
42  res[i] = tan(arg1[i] * DEGREES_TO_RADIANS);
44  SET_NULL_D(&res[i]);
45  }
46 
47  return 0;
48 }
double DCELL
Definition: gis.h:581
Definition: calc.h:13
int columns
Definition: calc.c:12
volatile int floating_point_exception
Definition: calc.c:9
#define DCELL_TYPE
Definition: raster.h:13
int f_tan(int argc, const int *argt, void **args)
Definition: xtan.c:20
Definition: calc.h:12
#define IS_NULL_D(x)
Definition: calc.h:30
#define SET_NULL_D(x)
Definition: calc.h:34
#define DEGREES_TO_RADIANS
Definition: xtan.c:18