If statement element-by-element for vector of arbitrary size

I need to emulate this VBA code in Matlab:

If M > 1 Then
    PR_NS = (kp * M ^ 2 / (km * M ^ 2 + 2)) ^ e1 _
          * (kp / (2 * k * M ^ 2 - km)) ^ e2
Else
    PR_NS = 1
End If

Where M is a column vector of arbitrary (unknown) size and other items (kp, km, e1, e2) are scalers.

The intent is to return a column vector PR_NS of the same size as M. Depending on each value of M, each value of PR_NS may either be 1 or the value resulting from the equation.

I know this is a very basic question, but I am a newbie and have an urgent need to implement this. Thanks!

Answer 1

[Todd]

Thanks! Very nice.

Answer 2

[Walter Roberson]

You could use a loop, but logical indexing is better:

PR_NS = ones(size(M));
M_in_range = M > 1;
PR_NS(M_in_range) = (kp .* M(M_in_range) .^ 2 ./ (km .* M(M_in_range) .^ 2 + 2)) .^ e1 .* (kp ./ (2 .* k .* M(M_in_range) .^ 2 - km)) .^ e2;