71 lines
1.5 KiB
C
71 lines
1.5 KiB
C
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/*
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* fractal
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* Written in 2020 by Lucas
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* CC0 1.0 Universal/Public domain - No rights reserved
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*
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* To the extent possible under law, the author(s) have dedicated all
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* copyright and related and neighboring rights to this software to the
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* public domain worldwide. This software is distributed without any
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* warranty. You should have received a copy of the CC0 Public Domain
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* Dedication along with this software. If not, see
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* <http://creativecommons.org/publicdomain/zero/1.0/>.
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*/
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "criticals.h"
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#include "util.h"
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size_t newton_iters = 100;
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static size_t idx = 0;
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static long double complex criticals[100];
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int
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behaves_critical(long double complex (*df)(long double complex),
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long double complex (*ddf)(long double complex), long double complex z,
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long double complex *crit, long double bailout, long double epsilon)
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{
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size_t i;
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for (i = 0; i < newton_iters && cabsl(z) < bailout; i++)
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z = z - df(z) / ddf(z);
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if (cabsl(df(z)) < epsilon) {
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*crit = z;
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return 1;
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}
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return 0;
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}
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void
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add_critical_point(long double complex z)
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{
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size_t i;
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if (idx >= nelems(criticals))
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return;
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for (i = 0; i < idx; i++)
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if (cabsl(z - criticals[i]) < 1.0e-9)
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return;
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criticals[idx++] = z;
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}
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size_t
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ncriticals(void)
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{
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return idx;
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}
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long double complex
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get_critical(size_t i)
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{
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if (i >= idx) {
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fprintf(stderr, "get_critical: index %zu out of range", i);
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exit(1);
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}
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return criticals[i];
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}
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