RWalib C Array Library User Guide > Trigonometric Functions > alibAcos
  

alibAcos
Returns the inverse cosine of each element in an array. The PV-WAVE API for this routine is the ACOS Function.
Prototypes
void alibAcosf( wvlong n, float *p, float *r )
void alibAcosd( wvlong n, double *p, double *r )
Parameters
n — (Input) The number of elements in the source array.
*p — (Input) The n-element source array.
*r — (Input/Output) The n-element destination array. On return, array r contains the inverse cosine of each element in array p. The operation can be done in-place, i.e., r can equal p.
Example
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "alib.h"
void main() {
   /* make up some input data for the examples */
      float  f0[4]={-1,0,0.5,1};
   /* make an output array */
      float  f[4];
   printf( "\n\n show 4-element vector f0" );
      alibinit( NULL, NULL, NULL, NULL );
      alibPrintArrayf( 1, 1, 1, 4, f0, NULL );
   printf( "\n\n show the inverse cosine of each element in f0" );
      alibAcosf( 4, f0, f );
      alibPrintArrayf( 1, 1, 1, 4, f, NULL );
   printf( "\n\n repeat the operation in-place;  print result as a matrix" );
      alibAcosf( 4, f0, f0 );
      alibPrintArrayf( 1, 1, 2, 2, f0, NULL );
}
 
Output:
 
 show 4-element vector f0
 
  -1.000e+00   0.000e+00   5.000e-01   1.000e+00
 
 show the inverse cosine of each element in f0
 
   3.142e+00   1.571e+00   1.047e+00   0.000e+00
 
 repeat the operation in-place;  print result as a matrix
 
   3.142e+00   1.571e+00
   1.047e+00   0.000e+00

Version 2017.0
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