#include <stdio.h>
read_data(file,x,nx,y,ndata)
    char *file;
    double *x, *y;
    int *nx, *ndata;
{
    FILE *fd;
    double *vector();
    double *xx, *yy;
    double dummy;
    char *b;
    char buf[1024];
    int i,j;

    fd = fopen (file, "r");
    if (fd == NULL)
    {
	perror (file);
	exit(1);
    }

/* figure out how many variables on the first line */
    if(NULL == fgets(b = buf, sizeof buf, fd))
	*buf = 0;

    *nx = 0;
    while(1)
    {
	while (*b == ' ' || *b == '\t' || *b == '\n')
		b++;
	if (*b == 0) break;

	(*nx)++;
	while (*b && *b != ' ' && *b != '\t' && *b != '\n')
		b++;
    }
    if (*nx == 1)
    {
	fprintf (stderr, "%s - no variables\n", file);
	exit(1);
    }
    if (*nx == 0)
    {
	fprintf (stderr, "%s - no data\n", file);
	exit(1);
    }
    printf ("%d variables\n", *nx - 1);

/* read the file once to findout how may data values */
    fseek (fd, 0L, 0);
    *ndata = 0;
    while (fscanf(fd, "%lf", &dummy) == 1)
	(*ndata)++;
    if ((*ndata) % (*nx))
    {
	fprintf (stderr, "%s - missing or extra data\n", file);
	exit(1);
    }
    *ndata /= *nx;
    printf ("%d observations\n", *ndata);
    (*nx)--;
    x = xx = vector((*nx)*(*ndata));
    y = yy = vector (*ndata);
    fseek (fd, 0L, 0);
    for (i = 0; i < *ndata; i++)
    {
	for (j = 0; j < *nx; j++)
	    fscanf (fd, "%lf", xx++);
	fscanf (fd, "%lf", yy++);
    }
    fclose (fd);
}

nonlinear_data(x1,nx1,y,epsilon,ndata,x2,nx2)
	double **x1, **x2, **y, **epsilon;
	int *nx1, *nx2, *ndata;
{
	int k,m,i;
	double *vector();

	*nx2 = (*nx1)*2;
	*x2 = vector (*nx2 * (*ndata));
	for (k=0; k< (*ndata); k++)
	   for (m=0; m< (*nx1); m++)
	       {
		*((*x2)+k*(*nx2)+m) = *((*x1)+k*(*nx1)+m);
	        *((*x2)+k*(*nx2)+(*nx1)+m)=*((*x1)+k*(*nx1)+m) *
	(*((*epsilon)+k) - *((*y)+k));
	       }
/******
	for (i=0; i< (*nx1)*(*ndata); i++)
	printf("in nonlinear_data:i=%3d, x1=%12.4f\n",i,*((*x1)+i));
	for (i=0; i< (*nx2)*(*ndata); i++)
	printf("in nonlinear_data:i=%3d, x2=%12.4f\n",i,*((*x2)+i));
******/
}