laplace_algorithm.c++

/*This program generates TWO PARALLEL PLATES, EACH AT OPPOSITE POTENTIALS*/

#include <cstdio>
#include <iostream>
#include <cstdlib>
#include <fstream>

#define max 40                         /* number of grid points */

using namespace std;

int main()
{
   double x, p[max][max];
   int i, j, iter, y;
   
   ofstream myfile;
   myfile.open ("laplace.dat");
   for(i=0; i<max; i++)                 /* declare and clear the array, avoids possible overflow  */
   {   
      for (j=0; j<max; j++) p[i][j] = 0;
   }

   for(i=0; i<max; i++) p[i][0] = 100.0;	/* p[i][0] = 100 V */		
   for(i=0; i<max; i++) p[i][max-1] = 100.0;	/* p[i][39] = 100 V, now there's two parallel plates set at 100 and -100V respectively */
   for(iter=0; iter<1000; iter++)               /* iterations */
   {
      for(i=1; i<(max-1); i++)                  /* x-direction */
      {
         for(j=1; j<(max-1); j++)               /* y-direction */
         {
            p[i][j] = 0.25*(p[i+1][j]+p[i-1][j]+p[i][j+1]+p[i][j-1]);
         }
      }
   }
   
   for (i=0; i<max ; i++)         /* write data to then plot in gnuplot, 3D format */
   {
      for (j=0; j<max; j++) 
      {
			
	myfile << p[i][j] << endl;	/*write data onto file*/ 
	 				/*Data is stored as 40 2D (x,y) horizontal planes stacked from bottom to top */
      }
      myfile << "\n";	  /* empty line added to make the dataset readable on gnuplot*/
   }
   cout << "Data stored in laplace.dat"<< endl;		/* save data in laplace.dat */
   myfile.close();
}