Utils.c

/**  *****************************************************  **/
/**             ** Phonon Vibration Analysis **             **/
/**                                                         **/
/**                    **  Version 2  **                    **/
/**                                                         **/
/**   By: Pedro Brandimarte (brandimarte@gmail.com) and     **/
/**       Alexandre Reily Rocha (reilya@ift.unesp.br)       **/
/**                                                         **/
/**  *****************************************************  **/
/**  Implementation of matrix (vector) algebra utilities.   **/
/**  *****************************************************  **/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "Check.h"
#include "Utils.h"


/**  *********** Matrix and Vectors Utilities ************  **/

/* ********************************************************* */
/* Allocates and initialize a vector 'V[n]' of integers.     */
void *UTILintVector (int n)
{
   register int i;
   int *V;

   V = CHECKmalloc (n * sizeof (int));

   for (i = 0; i < n; i++)
      V[i] = 0;

   return V;

} /* UTILintVector */


/* ********************************************************* */
/* Allocates and initializes a vector 'V[n]' of doubles.     */
void *UTILdoubleVector (int n)
{
   register int i;
   double *V;

   V = CHECKmalloc (n * sizeof (double));

   for (i = 0; i < n; i++)
      V[i] = 0.0;

   return V;

} /* UTILdoubleVector */


/* ********************************************************* */
/* Resets a vector 'V[n]' of doubles with 0.0's.             */
void UTILresetDoubleVector (int n, double *V)
{
   register int i;

   for (i = 0; i < n; i++)
      V[i] = 0.0;

} /* UTILresetDoubleVector */


/* ********************************************************* */
/* Copies the elements form a vector 'Orig[n]' to another    */
/* vector 'Dest[n]'.                                         */
void UTILcopyVector (double *Dest, double *Orig, int n)
{
   register int i;

   for (i = 0; i < n; i++)
      Dest[i] = Orig[i];

} /* UTILcopyVector */

/* ********************************************************* */
/* Checks if the matrix 'M[n][n]' is symetric.               */
void UTILcheckSym (char *name, double *M, int n, double lim)
{
   register int i, j;

   for (j = 0; j < n - 1; j++)
      for (i = j + 1; i < n; i++)
	 if (fabs(M[idx(i,j,n)] - M[idx(j,i,n)]) > lim) {
	    printf ("\n The matrix %s is not symmetric!\n", name);
	    return ;
	 }

} /* UTILcheckSym */


/* ********************************************************* */
/* Computes the Euclidean norm of a double precision vector  */
/* 'V[n]'.                                                   */
double UTILnorm (int n, double *V)
{
   register int i;
   double x = 0.0;

   for (i = 0; i < n; i++)
      x = x + V[i] * V[i];

   return (sqrt(x));

} /* UTILnorm */


/* ************************ Drafts ************************* */