X-Git-Url: https://hackdaworld.org/gitweb/?p=physik%2Fcomputational_physics.git;a=blobdiff_plain;f=bessel_1.c;fp=bessel_1.c;h=afc0a978f003160165356868429f55e4335fbd09;hp=0000000000000000000000000000000000000000;hb=dbec7a4f63c3acda2e68719cb98d85fd34c91afc;hpb=936dfe8d44eb6beeecb48b201db22bb0d9de9956

diff --git a/bessel_1.c b/bessel_1.c
new file mode 100644
index 0000000..afc0a97
--- /dev/null
+++ b/bessel_1.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <math.h>
+#include "g_plot.h"
+#include "general.h"
+
+#define EPSILON .0001
+#define MAX_L 100
+#define R_STEP 0.1
+#define MAX_R 30
+
+int main(int argc, char **argv) {
+	int l;
+	// int fd;
+	int i;
+	double r;
+	double t;
+	double delta=2*EPSILON;
+	double Jl,Jl_1;
+
+	/*
+	if(argc!=2) {
+		printf("usage: %s file\n"argv[0]);
+		return 1;
+	}
+	*/
+
+	// for(l=0:l<MAX_L;l++)
+	l=1;
+
+	for(r=0;r<MAX_R;r+=R_STEP) {
+
+	/* fd */
+	// fd=gp_init(argv[1]);
+
+	i=1;
+	t=1/(fak2(2*l-1));
+	Jl_1=t;
+	t=t/(2*l+1);
+	Jl=t;
+	delta=2*EPSILON;
+	while(delta>EPSILON) {
+		t*=-(r*r)/(2*i);
+		Jl_1+=t;
+		t*=(1./(2*l+1+i));
+		Jl+=t;
+		delta=absolute_value(t/Jl);
+		i++;
+	}
+	printf("%f %f %f (i=%d)\n",r,Jl,Jl_1,i);
+
+	}
+	// gp_close(fd);
+	return 1;
+}
+
+