Matrix with differential operators - HELP

Hello all,

I need some help of you!

I have a matrix of deferential operators (like the image in attachment) and i want to write it in a Matlab notation in order to multiply it with a matrix of functions.

Anyone can help me ?

Thanks in advance

Answer 1

[Azzi Abdelmalek]

%Example

syms x y
f=@(h) [diff(h,y) diff(h,x);diff(h,x) -diff(h,y)]
h=2*x+3*y
f(h)

[rodrigo]

Ok, but that is a matrix of derivates. I need a matrix with only de diferential operators in order to multiply it to another matrix.

Do you understand what i mean ? sorry if i can't explain ...

thanks

[Azzi Abdelmalek]

Maybe this is what you want

syms x y
f=@(h) [diff(h(1,1),y) diff(h(1,2),x);diff(h(2,1),x) -diff(h(2,2),y)]
h=[2*x+3*y 5*x+6*y;10*x+30*y 22*x-y]
f(h)

[rodrigo]

More or less.

I have the matrix "h" with variable size. because that i have to multiply the operators matrix with expressions matrix, and not what that.

Any idea ?

Answer 2

[rodrigo]

Anyone can help me please ? Azzi's idea did not work for what want.

Thanks

[Cedric]

What you want to achieve is still unclear to me. Do you need an "operator" which returns the analytical form of this matrix when applied to a function defined analytically/symbolically, or is it numeric?

Answer 3

[Lam Nguyen Van]

Take a look: https://www.mathworks.com/matlabcentral/answers/36580-operator-matrix-for-matrix-differentiation

function dNdv = diffmtx(v,N)

% v -vector m x 1 - sym array

% N - matrix m x n - sym array

rz = arrayfun(@(ii)diff(N(ii,:),v(ii)),(1:numel(v)).','un',0);

dNdv = cat(1,rz{:});

end