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MC_pinumerical.c
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MC_pinumerical.c
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#include <stdio.h>
#include <stdlib.h>
#include <time.h>
# include <math.h>
int main(void) {
srand(time(NULL));
int N=50000;
int i,counter = 0;
double error = 1e-10;
double oldPi = 1,newPi = 1;// initial values can't be zero!!!
double temp = 100,sum = 1;// temp is the evaluation for while loop
// for(i = 1; i <= N; i++) {
// if(i%2 == 1){
// sum -= (double) 1/(2*i+1);
// }
// else{
// sum += (double) 1/(2*i+1);
// }
// printf("After interation %d, PI = %f\n",i,(double) 4 * sum);
// }
// Please make a plot to tell when Pi is close to a constant
while(temp > error){
counter++;
if(counter%2 == 1){
sum -= (double) 1/(2*counter+1);
}
else{
sum += (double) 1/(2*counter+1);
}
oldPi = newPi;
newPi = sum ;
temp = (double)(fabs(newPi-oldPi))/oldPi;// abs() for integer only
printf("After interation %d, PI = %.12lf with error %.12lf\n",counter,(double) 4 * sum,temp);
}
return 0;
}