How to invert a 72x72 symbolic matrix?

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Hassan 2013-12-24

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评论： Hassan 2013-12-24

Hi,

Let's say I have a matrix A which have the size 72x72 and contatins only symbolic expressions. I want to solve the problem Ax=b, where b is a 72x1 vector with symbolic expressions. Is there some other way solve this problem than x = inv(A)*b or x=A\b, since these two types of solutions will take forever because of the symbolic matrix A?

Regards Hassan

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Answer 1

Wayne King 2013-12-24

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编辑：Wayne King 2013-12-24

在 MATLAB Online 中打开

What is the performance of linsolve() for symbolic expressions? I haven't tried it for such a big matrix, but have you tried that?

    syms a x y z;
    A = [cos(a) 0 sin(a); 0 1 0; -sin(a) 0 cos(a)];
    b = [x; y; z];
    [X,R] = linsolve(A,b)

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Hassan 2013-12-24

Thank you for the quick answer Wayne.

I reduced my A matrix to 6x6 just to try this function and it still takes a while to get the solution. My A matrix is a bit more complicated which ofcourse affects the computation time. However, I will give it a try for the full scale problem and hopefully I will get a solution at the end of this day :)

Regards Hassan

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