Modelamento

Boa tarde, preciso de ajuda para passar este código em c para fortran 90. Já montei o programa em fortran, porém não consigo o mesmo resultado, por favor, preciso de ajuda. #include <stdio.h> #include <stdlib.h> #include <math.h> /* if you don't have drand48 uncomment the following two lines */ /* #define drand48 1.0/RAND_MAX*rand #define srand48 srand */ #define max 40000 /* number of iterations */ #define size 401 /* size of grid array */ #define PI 3.1415926535897932385E0 #define seed 68111 /* seed for number generator */ main() { double angle, rad = 180.0; int i,j, x, y, dist, dir, step, trav; int grid, hit; int gauss_ran(); /* gaussian random number */ FILE *output; /* save data in dla.dat */ output = fopen("dla.dat","w"); for(i=0; i<size; i++) /* clear grid */ { for(j=0; j<size; j++) grid[j] = 0; } grid[200][200] = 1; /* one particle at the center */ srand48(seed); /* seed number generator */ for(i=0; i<max; i++) /* choose starting point */ { hit = 0; angle = (2*PI*drand48()); /* random angle */ x = (200+rad*cos(angle)); /* coordinates */ y = (200+rad*sin(angle)); dist = gauss_ran(); /* random number gaussian dist. */ if (dist<0) step=-1; /* move forwards or backwards */ else step=1; trav=0; while((hit==0)&&(x<399)&&(x>1)&&(y<399)&&(y>1)&&(trav<abs(dist))) { if(grid[x+1][y]+grid[x-1][y]+grid[x][y+1]+grid[x][y-1]>=1) { hit = 1; /* one neighbor is occupied */ grid[x][y] = 1; /* particle sticks, walk is over */ } else if(drand48() < 0.5) x+=step; /* move horizontally */ else y+=step; /* move vertically */ trav++; } } for(i=0; i<size; i++) /* print resulting grid */ { for(j=0; j<size; j++) { if(grid[j]==1) fprintf(output,"%d\t%d\n", i, j); } } printf("data stored in dla.dat\n"); fclose(output); } /*--------------------------end of main program-----------------------*/ /* generates random numbers with gaussian distribution using the */ /* Box-Mueller method */ int gauss_ran() { double fac, rr, r1, r2; static int old=0; /* have to be static so information */ static int mem; /* survives between function calls */ if (old==0) /* no random number left from */ { /* previous function call */ do { r1= 2.0*drand48()-1.0; /* choose random point in */ r2= 2.0*drand48()-1.0; /* the unit circle */ rr= r1*r1+r2*r2; }while ((rr>=1)||(rr==0)); fac=sqrt(-2*log(rr)/rr); mem=5000*r1*fac; /* save for next call */ old=1; /* set flag */ return((int)(5000*r2*fac)); } else /* return second number */ { /* from last call */ old=0; /* unset flag */ return mem; /* return number from last call */ } }