Why do I keep getting complex values from an if/else statement?

I'm trying to create values for a variable (called r2 in my code) using random numbers on [0,1] and an if/else statement. However, I keep getting complex values for r2 when that shouldn't happen. Is there an issue with the way I wrote my code? Here it is:

r = rand(25,1)

if r < 0.5

r2 = 0.5-sqrt(0.25-(r/2));

else

r2 = 0.5+sqrt((r/2)-0.25);

end

Answer 1

[Star Strider]

The problem is in the if block logic and the way MATLAB evaluates vectors.

if r < 0.5

implies:

if all(r < 0.5) 

that of course is not true, so the first section never evaluates.

You could put it in a loop, however this is more efficient:

r2 = (0.5-sqrt(0.25-(r/2))).*(r<0.5) + (0.5+sqrt((r/2)-0.25)).*(r>=0.5);

.

[Ryan Mahoney]

This worked. Thank you!

[Star Strider]

As always, my pleasure!