source: trunk/etc/src/yrms.c

/*
Copyright or © or Copr. MMSA team, LOCEAN Paris (2011)

This software is a framework for variational data assimilation in
numerical models.

This software is governed by the CeCILL license under French law and
abiding by the rules of distribution of free software.  You can  use,
modify and/ or redistribute the software under the terms of the CeCILL
license as circulated by CEA, CNRS and INRIA at the following URL
"http://www.cecill.info".

As a counterpart to the access to the source code and  rights to copy,
modify and redistribute granted by the license, users are provided only
with a limited warranty  and the software's author,  the holder of the
economic rights,  and the successive licensors  have only  limited
liability.

In this respect, the user's attention is drawn to the risks associated
with loading,  using,  modifying and/or developing or reproducing the
software by the user in light of its specific status of free software,
that may mean  that it is complicated to manipulate,  and  that  also
therefore means  that it is reserved for developers  and  experienced
professionals having in-depth computer knowledge. Users are therefore
encouraged to load and test the software's suitability as regards their
requirements in conditions enabling the security of their systems and/or
data to be ensured and,  more generally, to use and operate it in the
same conditions as regards security.

The fact that you are presently reading this means that you have had
knowledge of the CeCILL license and that you accept its terms.

YAO website : http://www.locean-ipsl.upmc.fr/~yao/
Contact : yao@locean-ipsl.upmc.fr
*/
// Contributor : Charles Sorror

/************************************************************************/
/*              yrms : is a part of Yao utilities and tools             */
/************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define BUFSIZE 80

int main (int argc, char *argv[])
{    /* . Syntaxe: yrms f1 f2 zspace [f3] */
     /* . Purpose: calculer l'erreur rms entre 2 trajectoires d'espace
                 dont les valeurs sont respectvement dans les fichiers
                 f1 et f2 passes en parametres qui doivent contenir
                 le meme nombre d'elements qui doit d'ailleurs etre
                 un multiple de zspace qui est la taille de l'espace
                 le resultat, {pour chaque pas d'espace, zspace} est
                 ecrit dans f3 s'il est mentionne sinon sur la sortie
                 standard.
                 la somme des rms est affichee a la fin
        . Warning: la detection de ligne blanche ou vide n'est pas geree
        . Compilation : cc -Wall -o yrms yrms.c -lm                     */

        FILE    *f1, *f2, *f3;
        char    buf1[BUFSIZE+1], buf2[BUFSIZE+1];
        int     zspace, rstelt, nbt;
        double  x1, x2, errsumt, errsumallt, rms, sumrms;

        if (argc<4 || argc > 5)
        {       printf("syntaxe error !!! : yrms f1 f2 zspace [f3]\n");
                exit(0);
        }

        if ((f1 = fopen(argv[1], "r")) <= 0)
        {       printf ("file1 %s not found !!!\n", argv[1]);
                exit(0);
        }
        if ((f2 = fopen(argv[2], "r")) <= 0)
        {       printf ("file2 %s not found !!!\n", argv[2]);
                exit(0);
        }
        if (argc==5)
        {       if ((f3 = fopen(argv[4], "w")) <= 0)
                {       printf ("failed while opening file3 %s !!!\n", argv[3]);
                        exit(0);
                }
        }
        else
                f3 = stdout;

        zspace = atoi(argv[3]);
        if (zspace<=0)
        {       printf ("zspace must be a integer greater than zero !!!\n");
                exit(0);
        }

        rstelt=0; nbt=0; errsumt=0.0; errsumallt=0.0, sumrms=0.0;
        while (1) /* boucle de */
        {       /* lecture paralle des 2 fichiers */
                if (fgets (buf1, BUFSIZE, f1) == NULL)
                {  /* fin du 1er fichier => fin du 2eme fichier */
                   if (fgets (buf2, BUFSIZE, f2) != NULL)
                   {  printf("erratum 1: the files have not the same size !!!\n");
                      exit(0);
                   }

                   /* fin: le nombre d'elt devait etre un multiple de zspace */
                   if (rstelt!=0)
                   {  printf("erratum 3: number of element is not o multiple of zspace\n");
                      exit(0);
                   }

                   /* fin fin */
                   break;
                }

                /* on doit pouvoir lire le 2eme fichier */
                if (fgets (buf2, BUFSIZE, f2) == NULL)
                {  printf("erratum 2: the files have not the same size !!!\n");
                   exit(0);
                }

                x1 = atof(buf1);        x2 = atof(buf2);
                //printf("x1=%f x2=%f \n", x1, x2);

                errsumt += ((x1-x2)*(x1-x2));
                errsumallt += errsumt;

                rstelt = (rstelt+1)%zspace;
                if (rstelt==0)
                {       //printf ("errsumt=%f \n", errsumt);
                        rms = sqrt(errsumt/zspace);
                        fprintf(f3, "%f\n",  rms);
                        errsumt = 0.0;
                        ++nbt;
                        sumrms += rms;
                }

        } /* fin du while de la boucle de lecture parallele */
        printf("SUMt(rms) = %30.20e\n", sumrms);

        /* rms sur tout la trajectoire */
        rms = sqrt(errsumallt/(zspace*nbt));
        printf("RMS(trajectoire::%i pas de temps) = %30.20e\n", nbt, rms);

        printf("yrms: process end normaly\n");
        return (0);
}