# Matrix Numerov Method in three dimensions

Hi can anybody help me to write the following equation in form of matrix by using Numerov's method. $$\left(\frac{d^2}{d x_1^2}+\frac{d^2}{d x_2^2}+\frac{d^2}{d x_3^2}+x^2_1+x^2_2+x^2_3+x_1x_2+x_2x_3+x_1x_3\right) u(x_1,x_2,x_3)=E u(x_1,x_2,x_3)\\$$

I hope there may exist a way to write this equation interms of tensors by using matrix Numerov's method.