Description
The shape of the resulting matrix is the same as the shape of f, but the degrees of the source module are different in an attempt to ensure that the result is homogeneous.
i1 : R = QQ[x,y,z];

i2 : f = matrix{{x^2y*z, x*y*z + z^4}, {x1, 2*y^2+z^21}}
o2 =  x2yz z4+xyz 
 x1 2y2+z21 
2 2
o2 : Matrix R < R

i3 : diff(x,f)
o3 =  2x yz 
 1 0 
2 2
o3 : Matrix R < R

i4 : diff(x^2y*z,f)
o4 =  3 x 
 0 0 
2 2
o4 : Matrix R < R
