ngspice/src/frontend/points.c

116 lines
2.5 KiB
C

/**********
Copyright 1990 Regents of the University of California. All rights reserved.
Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
**********/
#include "ngspice/ngspice.h"
#include "ngspice/cpdefs.h"
#include "ngspice/ftedefs.h"
#include "ngspice/dvec.h"
#include "ngspice/graph.h"
#include "ngspice/ftedbgra.h"
#include "points.h"
/* Returns the minimum and maximum values of a dvec. Returns a pointer
* to static data. If real is TRUE look at the real parts, otherwise
* the imag parts. */
double *
ft_minmax(struct dvec *v, bool real)
{
static double res[2];
register int i;
double d;
res[0] = HUGE;
res[1] = - res[0];
for (i = 0; i < v->v_length; i++) {
if (isreal(v))
d = v->v_realdata[i];
else if (real)
d = realpart(v->v_compdata[i]);
else
d = imagpart(v->v_compdata[i]);
if (d < res[0])
res[0] = d;
if (d > res[1])
res[1] = d;
}
return (res);
}
/* Figure out where a point should go, given the limits of the plotting
* area and the type of scale (log or linear).
*/
int
ft_findpoint(double pt, double *lims, int maxp, int minp, bool islog)
{
double tl, th;
if (pt < lims[0])
pt = lims[0];
if (pt > lims[1])
pt = lims[1];
if (islog) {
tl = mylog10(lims[0]);
th = mylog10(lims[1]);
return (int)(((mylog10(pt) - tl) / (th - tl)) *
(maxp - minp) + minp);
} else {
return (int)(((pt - lims[0]) / (lims[1] - lims[0])) *
(maxp - minp) + minp);
}
}
/* Will report the minimum and maximum in "reflection coefficient" space
*/
double *
ft_SMITHminmax(struct dvec *v, bool yval)
{
static double res[2];
register int i;
double d, d2;
res[0] = HUGE;
res[1] = - res[0];
for (i = 0; i < v->v_length; i++) {
if (isreal(v))
SMITH_tfm(v->v_realdata[i], 0.0, &d, &d2);
else
SMITH_tfm(realpart(v->v_compdata[i]), imagpart(v->v_compdata[i]),
&d, &d2);
/* Are we are looking for min/max X or Y ralue
*/
if (yval)
d = d2;
if (d < res[0])
res[0] = d;
if (d > res[1])
res[1] = d;
}
return (res);
}
int
SMITH_tfm(double re, double im, double *x, double *y)
{
double dnom;
dnom = (re + 1) * (re + 1) + im * im;
*x = (re * re + im * im - 1) / dnom;
*y = 2 * im / dnom;
return 0;
}