MATLAB: How can i substitute elements of a symbolic matrix with arrays of numbers

substitutionsymbolic matrix

Hi,

i have a symbolic matrix

   A(2*3) = [a_1 a_2 a_3; a_4 a_5 a_6];

also i have 20*1 arrays of numbers. such as

b_1(20,1),b_2(20,1),b_3(20,1),b_4(20,1),b_5(20,1).

i need to substitute elements of symbolic matrix with elements of array one at a time, lets say

a_1=b_1(1,1),a_2=b_2(1,1),a_3=b_3(1,1),a_4=b_4(1,1),a_5=b_5(1,1)

and keep substituting to the last elements of a_1=b_1(20,1), ….

can someone please give me a hint?

thank you in advance

Best Answer

arrayfun(@(K) subs(A, A, [b_1(K), b_2(K), b_3(K); b_4(K), b_5(K), b_6(K)]), 1:length(b_1), 'Uniform', 0)

Note that the substituting vector, [b_1(K), b_2(K), b_3(K); b_4(K), b_5(K), b_6(K)] must be the same shape as the vector of variables, A, for this to work.

An easier way to handle this would be

mat2cell( reshape([b_1, b_2, b_3, b_4, b_5, b_6], [], 3, 2), ones(1, length(b_1)), 3, 2 )

since really your A is not participating in the process.

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Otherwise:

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"for" loop around repmat() in order to build the diagonal vector, and then diag() that.

Or just use a nested "for" loop.

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