how to find the inverse of a 2x2xm matrix?

i have extracted a 2x2xm matrix from an s2p file and i want to find its inverse. how do i go about doing this?

the question is like this:

a(:,:,1) =

-0.6044 - 0.1389i -5.2117 -32.3236i -0.0019 - 0.0205i -0.6058 - 0.1386i

a(:,:,2) =

-0.5319 - 0.1475i -4.6956 -34.9899i -0.0016 - 0.0213i -0.5335 - 0.1473i

a(:,:,3) =

-0.4557 - 0.1551i -4.1408 -37.3825i -0.0014 - 0.0220i -0.4574 - 0.1549i

this is a 3D matrix a.i want an inverse such that: inv (a(:,:,1)) inv (a(:,:,2)) inv (a(:,:,3)) and i want a single command that coulod do it or a code so that the answer is still in the form of a 3D matrix.

Answer 1

[Andrei Bobrov]

a(:,:,1) =[-0.6044-0.1389i,  -5.2117-32.3236i;-0.0019-0.0205i,  -0.6058-0.1386i]
a(:,:,2) =[-0.5319-0.1475i,  -4.6956-34.9899i;-0.0016-0.0213i,  -0.5335-0.1473i]
a(:,:,3) =[-0.4557-0.1551i,  -4.1408-37.3825i;-0.0014-0.0220i,  -0.4574-0.1549i]

s = size(a);
e1 = eye(s(1:2));
for jj = s(3):-1:1
    b(:,:,jj) = a(:,:,jj)\e1;
end

[padoh]

ive entered the exact code in matlab n no output matrix b is generated and no error has occurred either

[Jan]

@padoh: Then use the debugger to step through the code line by line to find out, what's going own. It is a good idea to invest own effort when a problem is discussed in the forum. Do not wait for others to solve your problem.

Answer 2

[David Sanchez]

a=rand(2); % example matrix
b=inv(a)  % inverse matrix

[padoh]

this doesnt seem to solve the problem.

[padoh]

the question is like this:

a(:,:,1) =

-0.6044 - 0.1389i  -5.2117 -32.3236i
-0.0019 - 0.0205i  -0.6058 - 0.1386i

a(:,:,2) =

-0.5319 - 0.1475i  -4.6956 -34.9899i
-0.0016 - 0.0213i  -0.5335 - 0.1473i

a(:,:,3) =

-0.4557 - 0.1551i  -4.1408 -37.3825i
-0.0014 - 0.0220i  -0.4574 - 0.1549i

this is a 3D matrix a.i want an inverse such that: inv (a(:,:,1)) inv (a(:,:,2)) inv (a(:,:,3)) and i want a single command that coulod do it or a code so that the answer is still in the form of a 3D matrix.

[David Sanchez]

Maybe this is what you need:

A=rand(4,4,4);
B = zeros(size(A));
for k=1:size(A,3)
    B(:,:,k) = inv(A(:,:,k));
end