void dminmax(const double array[], const int pts, double *xmin, double *xmax);
void rotate2d(double x[], double y[], int pts, double angle);
void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);
int circle_pts(double theta);
/* filt.c */
void dminmax(const double array[], const int pts, double *xmin, double *xmax);
void rotate2d(double x[], double y[], int pts, double angle);
void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);
int circle_pts(double theta);
/* filt.c */