How to set a value according to a range without using a for loop?

Hello everybody.

I need to obtain r̂ values using next function:

where

I created an array gu to store all gu values from 0 to 128 using the function g.

The r values (to obtain r̂) are stored into an array called dct_values.

It is possible to compute r̂ values without using for loop (for example, when gu ⩽ r < gu+1) ?

Thanks for your help.

u  = [0:128];
gu = g(u);

[Walter Roberson]

u = 0:128;
gu = u.^2/90 + u/3;

Now consider discretize() of r with bins [-fliplr(gu), gu] . Then the bin-number can be used to index the replacement matrix [-128, -fliplr(u)-1, u, 127]

[Gabriel Melendez]

Thank you very much for your answer!