DSP Robotics Support

Posted: **Sun Sep 15, 2013 4:43 pm**

How to get (simplest way) a factional part in blue?
Like 4.543 -> 0.543
rndint(x) works differently than green int philosophy.

Posted: **Sun Sep 15, 2013 4:56 pm**

out = in-rndint(in);

Posted: **Sun Sep 15, 2013 4:58 pm**

Nope. Check the numbers with fraction above #.5, like 3.8
Code int rounds up or down. Green integer splits the integer and fractional part.

Posted: **Sun Sep 15, 2013 4:59 pm**

Yeah... posted without checking (or thinking!)... Sorry.

Posted: **Sun Sep 15, 2013 5:07 pm**

out = in - rndint(in-0.5);

But only with positive values

For negative and positive values this looks like it works:

streamin in;
streamout out;
float adj;

adj = 0.5 - (1 & (in<0));

out = in - rndint(in-adj);

(the assembly people can give you a proper solution)

EDIT - final - DOESN'T WORK WITH FLOATS THAT ARE ALREADY INTEGERS... I'll shut up now. :oops:

Posted: **Sun Sep 15, 2013 5:16 pm**

Need for both - positive and negative values.

Posted: **Sun Sep 15, 2013 5:20 pm**

Was editing last post when you replied... but as I said the assembly guys will give you something much better but this does seem to work.

Posted: **Sun Sep 15, 2013 5:20 pm**

Yeah, just came to similar thing, but I was wondering - if there is a simpler, "one operation" way.

Posted: **Sun Sep 15, 2013 7:59 pm**

This doesn't look simpler, but actually it's a lot faster.

Posted: **Sun Sep 15, 2013 9:02 pm**

for something that looks simple...

out = in%1;

I missed that there's a modulus divide. :lol:

how to get a fraction in blue