Histogram of Gradient Matrix

Given a Matrix for example:

I need two Compuation Matrix such that

Gx =

Gy =

I am trying using gradient but not getting the exact results.

I also need to calculate the Magnitude of Gx and Gy such that my final matrix results as:

Resultant Matrix :

Also need to caluclate the Angle of Gx and Gy (arctan(Gy/Gx)) degree.

All element values should be rounded off in all the matrix.

I need a general code which do not depend(size of input matrix) on matrix rows and coloumns of the given input matrix.

Please help with MATLAB Code

[David Hill]

What is the multivariate equation used to generation your given matrix? You can't generate the gradients without knowing the equation or x/y streams.