Symbol matrix function differentiation

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chen xy
chen xy 2013-3-3
1.The function 'diff' seems could only work with one-element variable 'v',
diff(f,v); % f(v), v is a one-lelement variable
while I would like do differentiation on a symbol matrix
diff(F, V); % F(V), V is a symbol matrix variable
2.If I make differentiation to each element of the symbol matrix, and obtain the result of diff(F, V), while the result is in element by element format,
[g1(v_i), g2(v_i), ..., gn(v_i)]
so I want to know are there some methods to make the result in symbol matrix variable format like this?
g(V)
3.for example
diff(x^T*A*x, x) = A^T*x + A*x; % A is a constant matrix, x is a vector

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Walter Roberson
Walter Roberson 2013-3-4
编辑：Walter Roberson 2013-3-4
If you want the result to be like in your (2) above, then use a "for" loop, or use
g = feval(symengine, 'zip', F, V, 'diff');
or use
g = cell2mat(arrayfun(@diff, F, V, 'Uniform', 0));
You might be able to just use
g = arrayfun(@diff, F, V);
but I think I recall seeing that have problems with arrayfun expecting numeric results.
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chen xy
chen xy 2013-3-5
If A isn't square, "x.'*A*x" will be wrong for matrix dimensions.

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