RWalib C Array Library User Guide > Exponentiation and Logarithms > alibPow
  

alibPow
General powers for scalar or array arguments, element-wise. The PV-WAVE API for this routine is the Exponentiation Operator ^.
Prototypes
void alibPowf( wvlong m, wvlong n, float *p, float *q, float *r )
void alibPowd( wvlong m, wvlong n, double *p, double *q, double *r )
void alibPowc( wvlong m, wvlong n, COMPLEX *p, COMPLEX *q, COMPLEX *r )
void alibPowz( wvlong m, wvlong n, DCOMPLEX *p, DCOMPLEX *q, DCOMPLEX *r )
Parameters
m — (Input) The number of elements in the first array operand. A value of 0 indicates that the first operand is a scalar.
n — (Input) The number of elements in the second array operand. A value of 0 indicates that the second operand is a scalar. If both operands are arrays then n must equal m.
*p — (Input) The pointer to the first operand.
*q — (Input) The pointer to the second operand.
*r — (Input/Output) The destination array. On return, array r contains argument p to the power of argument q, element-wise. The operation can be done in-place, i.e., r can equal p or q.
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=0.25, f1[4]={0.5,1.5,2.5,3.5}, f2[4]={0.5,-0.5,1.5,-1.5};
  /* make an output array */
    float    f[4];
  printf( "\n\n show scalar f0 and 4-element vectors f1 and f2" );
    alibinit( NULL, NULL, NULL, NULL );
    alibPrintArrayf( 1, 1, 1, 1, &f0, NULL );
    alibPrintArrayf( 1, 1, 1, 4, f1, NULL );
    alibPrintArrayf( 1, 1, 1, 4, f2, NULL );
  printf( "\n\n show f0 to the power f1, element-wise" );
    alibPowf( 0, 4, &f0, f1, f );
    alibPrintArrayf( 1, 1, 1, 4, f, "%12.4e" );
  printf( "\n\n show f1 to the power f0, element-wise" );
    alibPowf( 4, 0, f1, &f0, f );
    alibPrintArrayf( 1, 1, 1, 4, f, NULL );
  printf( "\n\n show f1 to the power f2, element-wise" );
    alibPowf( 4, 4, f1, f2, f );
    alibPrintArrayf( 1, 1, 1, 4, f, NULL );
  printf( "\n\n repeat the operation in-place;  print result as a matrix" );
    alibPowf( 4, 4, f1, f2, f1 );
    alibPrintArrayf( 1, 1, 2, 2, f1, NULL );
}
 
Output:
 
 show scalar f0 and 4-element vectors f1 and f2
 
   2.500e-01
 
   5.000e-01   1.500e+00   2.500e+00   3.500e+00
 
   5.000e-01  -5.000e-01   1.500e+00  -1.500e+00
 
 show f0 to the power f1, element-wise
 
  5.0000e-01  1.2500e-01  3.1250e-02  7.8125e-03
 
 show f1 to the power f0, element-wise
 
   8.409e-01   1.107e+00   1.257e+00   1.368e+00
 
 show f1 to the power f2, element-wise
 
   7.071e-01   8.165e-01   3.953e+00   1.527e-01
 
 repeat the operation in-place;  print result as a matrix
 
   7.071e-01   8.165e-01
   3.953e+00   1.527e-01

Version 2017.0
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