ported chaos to the Library Template, now with libchaos support

svn path=/trunk/externals/bbogart/chaos/; revision=15625

1 files changed, 0 insertions, 90 deletions

diff --git a/lyapunov.c b/lyapunov.c
deleted file mode 100644
index 04153ba..0000000
--- a/lyapunov.c
+++ /dev/null
@@ -1,90 +0,0 @@
-#include <stdio.h>
-#include <math.h>
-#include "lyapunov.h"
-
-#define LY_ITERATIONS 50000
-
-//#define LY_ABERATION 1e-6
-#define LY_ABERATION 10e-15
-
-/**
- * this expects the fractal to already be stable (ie iterate it a few hundred/thousand times).
- 
- Steps as described by Julian Sprott
- 1. Start with any initial condition in the basin of attraction
- 2. Iterate until the orbit is on the attractor
- 3. Select (almost any) nearby point (separated by d0)
- 4. Advancce both orbits one iteration and calculate the new separation d1
- 5. Evaluate log(d1/d0) in any convienient base
- 6. Readjust one orbit so its separation is d0 in the same direction as d1
- 7. Repeat steps 4-6 many times and calculate the average of step 5
- */
-double lyapunov_eval(void *fractal, t_gotfn calc, int var_count, double *vars, double *test) {
-	int i, j;
-	double exponent = 0.0, sum = 0.0, d2, df, rs;
-	double diff[MAX_VARS];
-	
-	for(i = 0; i < LY_ITERATIONS; i++) {
-		// 4. iterate each set
-		calc(fractal, vars);
-		calc(fractal, test);
-		// 5. Evaluate
-		d2 = 0.0;
-		for(j = 0; j < var_count; j++) {
-			diff[j] = test[j] - vars[j];
-			//fprintf(stderr, "vars[%d] = %0.30f\n test[%d] = %0.30f\n  diff[%d] = %0.30f\n",
-			//	j, vars[j], j, test[j], j, diff[j]);
-			d2 += diff[j] * diff[j];
-		}
-		df = 1000000000000.0 * d2;
-		rs = 1.0 / sqrt(df);
-		sum += log(df);
-		exponent = 0.721347 * sum / i;
-		//fprintf(stderr, "%d\n  d2 = %0.30f\n  df = %0.30f\n  rs = %0.30f\n  sum = %0.30f\nexponent = %0.30f\n\n",
-		//	i, d2, df, rs, sum, exponent);
-		// 6. adjust the orbit under test
-		for(j = 0; j < var_count; j++) {
-			test[j] = vars[j] + (rs * (test[j] - vars[j]));
-		}
-	}
-	return exponent;
-}
-
-double lyapunov(void *fractal, t_gotfn calc, int var_count, double *vars) {
-	int i;
-	double test[MAX_VARS];
-	
-	// 1. + 2. 'vars' is expected to be ready to start computing
-	// 3. create a test set of variables
-	test[0] = vars[0] + LY_ABERATION;
-	for(i = 1; i < var_count; i++) { test[i] = vars[i]; }
-	
-	return lyapunov_eval(fractal, calc, var_count, vars, test);
-}
-
-double *lyapunov_full(void *fractal, t_gotfn calc, int var_count, double *vars, double *results) {
-	int i, j;
-	double initial[MAX_VARS];
-	double test[MAX_VARS];
-	
-	// save the starting values
-	for(i = 0; i < var_count; i++) {
-		initial[i] = vars[i];
-	}
-	for(i = 0; i < var_count; i++) {
-		// aberate each variable in turn
-		for(j = 0; j < var_count; j++) {
-			if (j == i) {
-				test[j] = vars[j] + LY_ABERATION;
-			} else {
-				test[j] = vars[j];
-			}
-		}
-		results[i] = lyapunov_eval(fractal, calc, var_count, vars, test);
-		// set the vars back the initial values
-		for(j = 0; j < var_count; j++) {
-			vars[j] = initial[j];
-		}
-	}
-	return results;
-}