The triple integral I= ∫∫∫(on the domain V) f(x,y,z) dV cannot be calculated either analytically in the general case or even numerically.

Recently we have seen many attempts, some using the Schrödinger equation in QM!?, to evaluate its integral, but unfortunately all ended in failure.

Perhaps this is why Einstein introduced tensor algebra just to estimate the total garavity energy near the sun, as follows:

U= ∫∫∫ G(x,y,z) dx dy dz

.

To our knowledge the only numerical method we know for this triple integral is [1],

i= f(x1,y1,z1) . SW1 +f(x2,y2,z2) . SW2. . . + f(x27,y27,z27) . SW27

Where SW,s are the statistical weights of the triple integral.

Numerical examples,

I=∫∫∫[0,1]^3 f(x,y,z) dx dy dz

for f(x)=x or f(x)=y or f(x)=z

then I is almost the same and is equal to 13.6

for f(x)=x^2 or f(x)=y^2 or f(x)=z^2

then I have almost the same value and equals 11

for f(x)=x+y+z,

I = 40.54

1- A rigorous reform of physics and mathematics.