Usings subs on matrices ?

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Matthieu on 31 Oct 2013
Commented: Matthieu on 31 Oct 2013
Hi everyone,
I'm trying to substitute variables in a matrix, but I run in something a little bit weird. When using the command "C = subs(C, exp1, exp2)", the result is not the matrix that I would have had if I had done the same substitution for all elements of C. How can it be ?
Matthieu on 31 Oct 2013
Hi Jos,
So my matrix C was 5x5 matrix with quite complicated expression, but to make it simple let's say that all coefficients are of the form : (xi - xj) * lp * exp where exp is a symbolic expression, xi (i=1:5) and lp are symbolic variables.
Now, I have a variable y which value is 0 and my script goes :
C = subs(C, xi, y);
which I would expect to give -xj * lp * exp, but what I actually get is lp. When I do the substitution on the expression only, I get, the right result.
Any idea ?

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Answers (1)

Johannes Korsawe
Johannes Korsawe on 31 Oct 2013
C(C==exp1) = exp2;


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