GRASS GIS 8 Programmer's Manual  8.5.0dev(2024)-d12eea5925
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xexp.c
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1 #include <math.h>
2 
3 #include <grass/gis.h>
4 #include <grass/raster.h>
5 #include <grass/calc.h>
6 
7 /**********************************************************************
8 exp(x) computes e raised to power x
9 exp(x,y) computes x raised to power y
10 
11  if floating point exception occurs during the evaluation of exp(x)
12  or exp(x,y) the result is NULL
13 **********************************************************************/
14 
15 int f_exp(int argc, const int *argt, void **args)
16 {
17  DCELL *res = args[0];
18  DCELL *arg1 = args[1];
19  DCELL *arg2;
20  int i;
21 
22  if (argc < 1)
23  return E_ARG_LO;
24  if (argc > 2)
25  return E_ARG_HI;
26 
27  if (argt[0] != DCELL_TYPE)
28  return E_RES_TYPE;
29 
30  if (argt[1] != DCELL_TYPE)
31  return E_ARG_TYPE;
32 
33  arg2 = (argc > 1) ? args[2] : NULL;
34 
35  for (i = 0; i < columns; i++)
36  if (IS_NULL_D(&arg1[i]))
37  SET_NULL_D(&res[i]);
38  else if (argc > 1 && IS_NULL_D(&arg2[i]))
39  SET_NULL_D(&res[i]);
40  else if (argc > 1 && arg1[i] < 0 && arg2[i] != ceil(arg2[i]))
41  SET_NULL_D(&res[i]);
42  else {
44  res[i] = (argc > 1) ? pow(arg1[i], arg2[i]) : exp(arg1[i]);
46  SET_NULL_D(&res[i]);
47  }
48 
49  return 0;
50 }
@ E_RES_TYPE
Definition: calc.h:14
@ E_ARG_TYPE
Definition: calc.h:13
@ E_ARG_HI
Definition: calc.h:12
@ E_ARG_LO
Definition: calc.h:11
volatile int floating_point_exception
Definition: calc.c:8
#define SET_NULL_D(x)
Definition: calc.h:32
int columns
Definition: calc.c:11
#define IS_NULL_D(x)
Definition: calc.h:28
#define NULL
Definition: ccmath.h:32
double DCELL
Definition: gis.h:629
#define DCELL_TYPE
Definition: raster.h:13
int f_exp(int argc, const int *argt, void **args)
Definition: xexp.c:15