If statement with 2 matrices

Hi guys,

I got the following question regarding applying a if statement in the correct way:

I have a matrix A (2856x48) containing values.

I have a matrix B (2856x48) containing ones and zeros.

And I have 2 boundary values C and D.

Now I want to check for each value in A whether it exceeds its corresponding boundary value. And if so, the value in A should be set to the boundary value.

So, let's say the value B(1,1)= 0. In this case the value of A(1,1) should be checked whether it exceeds the boundary value C and if so the value in A(1,1) should be set to C.

Another example, let's say B(2,3)= 1. In this case the value of A(2,3) should be checked whether it exceeds the boundary value D and if so the value in A(2,3) should be set to D.

So boundary value C corresponds to a zero-value in B & D corresponds to a one-value in B.

Can anyone help me out?

Answer 1

[Lessmann]

Hi,

if statements on matrices can often be realized with logical indexing. Assuming the matrix B is of type 'logical', your if statement is:

 A(A>D &  B) = D
 A(A>C & ~B) = C

Answer 2

[Adam]

Something like this ought to work, though it is untested off the top of my head:

boundaryVals = B * C + ( 1 - B ) * D;

A( A > boundaryVals ) = boundaryVals( A > boundaryVals );