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argyllcms/rspl/cw1.c
2026-08-20 20:28:40 +01:00

310 lines
6.8 KiB
C

/************************************************/
/* Investigate various curve approximations */
/************************************************/
/* Discrete regularized spline versions */
/* Test variable grid spacing in 1D */
/* Author: Graeme Gill
* Date: 4/10/95
* Date: 5/4/96
*
* Copyright 1995, 2013 Graeme W. Gill
*
* This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :-
* see the License.txt file for licencing details.
*/
#undef DIAG
#undef DIAG2
#undef GLOB_CHECK
#define AVGDEV 0.0 /* Average deviation of function data */
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <math.h>
#include "copyright.h"
#include "aconfig.h"
#include "numlib.h"
#include "rspl.h"
#include "plot.h"
#include "ui.h"
double lin();
void usage(void);
#define TRIALS 1 /* Number of random trials */
#define XRES 100 /* Plotting res */
#define PNTS1 10
#define GRES1 100
/* Function that we're approximating */
static double func(double val) {
double out;
int sgn = 0;
if (val < 0.0) {
sgn = 1;
val = -val;
}
out = pow(val, 2.5);
if (sgn)
out = -out;
return out;
}
/* Grid spacing power */
#define GRIDPOW 1.5
/* Scattered data sample spacing power */
#define SAMPPOW 1.3
co test_points[PNTS1];
double ipos[GRES1];
double *iposes[1] = { ipos };
double powlike(double vv, double pp);
void usage(void) {
fprintf(stderr,"Test 1D rspl interpolation variable grid spacing\n");
fprintf(stderr,"Author: Graeme W. Gill\n");
fprintf(stderr,"usage: c1 [options]\n");
fprintf(stderr," -s smooth Use given smoothness (default 1.0)\n");
exit(1);
}
int main(int argc, char *argv[]) {
int fa,nfa; /* argument we're looking at */
int i,j, n;
double x;
double xx1[XRES];
double yy1[6][XRES];
double xx2[XRES];
double yy2[6][XRES];
rspl *rss; /* incremental solution version */
datai low,high;
int gres[MXDI];
double smooth = 1.0;
double avgdev[MXDO];
low[0] = 0.0;
high[0] = 1.0;
avgdev[0] = AVGDEV;
error_program = "c1";
check_if_not_interactive();
/* Process the arguments */
for(fa = 1;fa < argc;fa++) {
nfa = fa; /* skip to nfa if next argument is used */
if (argv[fa][0] == '-') { /* Look for any flags */
char *na = NULL; /* next argument after flag, null if none */
if (argv[fa][2] != '\000')
na = &argv[fa][2]; /* next is directly after flag */
else {
if ((fa+1) < argc) {
if (argv[fa+1][0] != '-') {
nfa = fa + 1;
na = argv[nfa]; /* next is seperate non-flag argument */
}
}
}
if (argv[fa][1] == '?')
usage();
/* smoothness */
else if (argv[fa][1] == 's' || argv[fa][1] == 'S') {
fa = nfa;
if (na == NULL) usage();
smooth = atof(na);
}
else
usage();
} else
break;
}
/* Only one trial */
for (n = 0; n < TRIALS; n++) {
double lrand = 0.0; /* Amount of level randomness */
int pnts;
int fres;
pnts = PNTS1;
fres = GRES1;
gres[0] = fres;
/* Create the object */
rss = new_rspl(RSPL_NOFLAGS,
1, /* di */
1); /* fdi */
/* For each grid spacing test */
for (j = 0; j < 2; j++) {
for (i = 0; i < pnts; i++) {
double val, out;
val = i/(pnts - 1.0);
if (j == 0) { /* Linear */
// out = func(val + d_rand(-0.001, 0.001));
out = func(val);
test_points[i].p[0] = val;
test_points[i].v[0] = out;
} else { /* power 2.0 grid spacing */
val = pow(val, SAMPPOW); /* sample point spacing */
// out = func(val + d_rand(-0.001, 0.001));
out = func(val);
val = powlike(val, 1.0/GRIDPOW); /* To grid spacing */
test_points[i].p[0] = val;
test_points[i].v[0] = out;
}
}
/* Set grid position info */
for (i = 0; i < gres[0]; i++) {
double val, out;
val = i/(gres[0] - 1.0);
if (j == 1)
val = powlike(val, 1.0/GRIDPOW); /* To grid spacing */
ipos[i] = val;
}
rss->fit_rspl(rss,
0,
test_points, /* Test points */
pnts, /* Number of test points */
low, high, gres, /* Low, high, resolution of grid */
NULL, NULL, /* Default data scale */
smooth, /* Smoothing */
avgdev, /* Average deviation */
j == 0 ? NULL : iposes); /* iwidth */
/* Show the result full scale */
for (i = 0; i < XRES; i++) {
co tp; /* Test point */
x = i/(double)(XRES-1);
xx1[i] = x;
yy1[0][i] = func(x);
tp.p[0] = x;
if (j == 1)
tp.p[0] = powlike(tp.p[0], 1.0/GRIDPOW); /* Grid spacing input */
rss->interp(rss, &tp);
yy1[1+j][i] = tp.v[0];
if (yy1[1+j][i] < -0.2)
yy1[1+j][i] = -0.2;
else if (yy1[1+j][i] > 1.2)
yy1[1+j][i] = 1.2;
}
/* Show the result magnified */
for (i = 0; i < XRES; i++) {
co tp; /* Test point */
x = i/(double)(XRES-1);
x *= 0.1;
xx2[i] = x;
yy2[0][i] = func(x);
tp.p[0] = x;
if (j == 1)
tp.p[0] = powlike(tp.p[0], 1.0/GRIDPOW); /* Grid spacing input */
rss->interp(rss, &tp);
yy2[1+j][i] = tp.v[0];
if (yy2[1+j][i] < -0.2)
yy2[1+j][i] = -0.2;
else if (yy2[1+j][i] > 1.2)
yy2[1+j][i] = 1.2;
}
}
printf("Full scale: Black = ref, Red = even, Green = pow2\n");
do_plot6(xx1,yy1[0],yy1[1],yy1[2],NULL,NULL,NULL,XRES);
printf("Magnified: Black = ref, Red = even, Green = pow2\n");
do_plot6(xx2,yy2[0],yy2[1],yy2[2],NULL,NULL,NULL,XRES);
}
return 0;
}
/* A power-like function, based on Graphics Gems adjustment curve. */
/* Avoids "toe" problem of pure power. */
/* Adjusted so that "power" 2 and 0.5 agree with real power at 0.5 */
double powlike(double vv, double pp) {
double tt, g;
if (pp >= 1.0) {
g = 2.0 * (pp - 1.0);
vv = vv/(g - g * vv + 1.0);
} else {
g = 2.0 - 2.0/pp;
vv = (vv - g * vv)/(1.0 - g * vv);
}
return vv;
}
/******************************************************************/
/* Error/debug output routines */
/******************************************************************/
/* Next u function done with optimization */
/* Structure to hold data for optimization function */
struct _edatas {
rspl *rss;
int j;
}; typedef struct _edatas edatas;
#ifdef GLOB_CHECK
/* Overall Global optimization method */
/* Definition of the optimization function handed to powell() */
double efunc2(void *edata, double p[])
{
int j;
double rv;
rspl *rss = (rspl *)edata;
for (j = 0; j < rss->nig; j++) /* Ugg */
rss->u[j].v = p[j];
rv = rss->efactor(rss);
#ifdef DIAG2
/* printf("%c%e",cr_char,rv); */
printf("%e\n",rv);
#endif
return rv;
}
solveu(rss)
rspl *rss;
{
int j;
double *cp;
double *s;
cp = dvector(0,rss->nig);
s = dvector(0,rss->nig);
for (j = 0; j < rss->nig; j++) /* Ugg */
{
cp[j] = rss->u[j].v;
s[j] = 0.1;
}
powell(rss->nig,cp,s,1e-7,1000,efunc2,(void *)rss);
}
#endif /* GLOB_CHECK */