import numpy

slices = 100.

bound = 10.

width = 2.*bound/slices

enot = 8.85*10**-12

rho = (1.5*10**-7)/(8*bound**3)

x = numpy.arange(0,2*bound, width)
y = numpy.arange(0,2*bound, width)
z = numpy.arange(0,2*bound, width)

xx = numpy.zeros(x.size)
yy = numpy.zeros(y.size)
zz = numpy.zeros(z.size)

for i in range(0,x.size):
    xx[i] = -bound + i*width
    yy[i] = -bound + i*width
    zz[i] = -bound + i*width

v = numpy.array([xx,yy,zz])


change = 1.
while change < 2:
    for i in range(1, xx.size-1):
            v[i,i,i] = v[i+1,i,i]+v[i-1,i,i]
            for j in range(1, xx.size-1):
                v[j,j,j] = v[j,j+1,j]+v[j,j-1,j]
                for k in range(1, xx.size-1):
                    v[k,k,k] = v[k,k,k+1]+v[k,k,k-1]
    v = (1./6)*v + (width**2/6*enot)*rho
    change = change + 1