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qmc-lttc/variance_hydrogen.c
2021-04-25 20:02:47 +02:00

42 lines
985 B
C

#include "hydrogen.h"
int main() {
const double a[6] = {0.1, 0.2, 0.5, 1., 1.5, 2.};
const int sizex = 50;
double energy, r[3], sigma;
double x[sizex], dx, w, wsum, dV, e_tmp;
dx = 10.0 / (sizex - 1);
for (int i = 0; i < sizex; ++i) {
x[i] = -5.0 + i * dx;
}
dV = dx * dx *dx;
for (int l = 0; l < 6; ++l) {
energy = 0.0;
sigma = 0.0;
wsum = 0.0;
for (int i = 0; i < sizex; ++i) {
r[0] = x[i];
for (int j = 0; j < sizex; ++j) {
r[1] = x[j];
for (int k = 0; k < sizex; ++k) {
r[2] = x[k];
w = psi(a[l], r, 3) * psi(a[l], r, 3) * dV;
wsum += w;
e_tmp = e_loc(a[l], r, 3);
energy += w * e_tmp;
sigma += w * e_tmp * e_tmp;
}
}
}
energy = energy / wsum;
sigma = sigma / wsum;
sigma -= energy * energy;
printf("a = %.2lf E = %.5lf Sigma^2 = %.5lf\n", a[l], energy, sigma);
}
return 0;
}