spline *spline_read(FILE *fp)
{
  int        i, length;
  spline *s;

  /* read header */
  if ( fscanf(fp," Spline: length:%u",&length) < 1)
    return NULL;
  s = spline_create(length);

  /* read xlist */
  fscanf(fp," xlist:");
  for ( i = 0; i < length; i++ )
    if ( fscanf(fp,"%lf",&(s->xlist[i])) < 1 )
      spline_error("spline_read: fscanf error");
  /* read ylist */
  fscanf(fp," ylist:");
  for ( i = 0; i < length; i++ )
    if ( fscanf(fp,"%lf",&(s->ylist[i])) < 1 )
      spline_error("spline_read: fscanf error");
  /* read Mlist */
  fscanf(fp," Mlist:");
  for ( i = 0; i < length; i++ )
    if ( fscanf(fp,"%lf",&(s->Mlist[i])) < 1 )
      spline_error("spline_read: fscanf error");

  return s;
}