alibPow

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 2017.1