added ignore file

[physik/ising.git] / ising.c

diff --git a/ising.c b/ising.c
index cb89d8a..4ff3ba8 100644 (file)
--- a/ising.c
+++ b/ising.c
@@ -11,22 +11,33 @@
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
+#include <time.h>
+
 #include "dfbapi.h"
 
-#define X 50
-#define Y 50
-#define MAX_T 200
+#define X 200
+#define Y 200
+#define MAX_T 10
 
 int main(int argc, char **argv)
 {
  unsigned char *atom;
+ char *arg_v[4];
+ char m_text[64];
+ char t_text[64];
+ char b_text[64];
  int max_x,x_c,max_y,y_c;
- int i,j;
+ int i;
+ int count_p;
  unsigned int T;
- double M;
+ double S;
+ int M;
  double beta;
  double delta_e;
 
+ /* random stuff*/
+ srand(time(0));
+
  /* display stuff */
  d2_lattice d2_l;
 
@@ -43,25 +54,44 @@ int main(int argc, char **argv)
  /* begin at T=0 M=1 situation */
  memset(atom,0,max_x*max_y*sizeof(unsigned char));
 
+ S=1; /* i have no idea! */
+ 
  for(T=1;T<MAX_T;T++)
  {
-  beta=1.0/T; /* k_B = 1 */
-  /* do N*N itterations, we will need more */
-  for(i=0;i<max_x*max_y;i++)
+  beta=5.0/T; /* k_B = 1 */
+  /* do 100 itterations, we will need more */
+  for(i=0;i<100;i++)
   {
 
- for(x_c=0;x_c<max_x-1;x_c++)
+ M=0;
+ for(x_c=0;x_c<max_x;x_c++)
  {
-  for(y_c=0;y_c<max_y-1;y_c++)
+  for(y_c=0;y_c<max_y;y_c++)
   {
-   delta_e=0;
-   // delta_e+=(-1*(int)(atom
+   count_p=0;
+   if((*(atom+x_c+((y_c+max_y+1)%max_y)*max_x))&1) ++count_p;
+   if((*(atom+x_c+((y_c+max_y-1)%max_y)*max_x))&1) ++count_p;
+   if((*(atom+((max_x+x_c+1)%max_x)+y_c*max_x))&1) ++count_p;
+   if((*(atom+((max_x+x_c-1)%max_x)+y_c*max_x))&1) ++count_p;
+   if(((*(atom+x_c+y_c*max_x))&1)==0) count_p=4-count_p;
+   delta_e=(2*count_p-4)*S;
+   if(delta_e<0) *(atom+x_c+y_c*max_x)=(*(atom+x_c+y_c*max_x)+1)&1;
+   else
+   {
+    if(1.0*rand()/RAND_MAX<exp(-1.0*delta_e*beta))
+     *(atom+x_c+y_c*max_x)=(*(atom+x_c+y_c*max_x)+1)&1;
+   }
+   if((*(atom+x_c+y_c*max_x))&1) ++M;
   }
-  
  }
-
+  sprintf(t_text,"temp = %d",T);
+  arg_v[1]=t_text;
+  sprintf(b_text,"beta = %f",beta);
+  arg_v[2]=b_text;
+  sprintf(m_text,"magn = %f",1.0-2.0*M/(max_x*max_y));
+  arg_v[3]=m_text;
+  d2_lattice_draw(&d2_l,0,0,3,arg_v);
   }
-  d2_lattice_draw(&d2_l,0,0,0,NULL);
  }
 
  getchar();