adccommunitymod (AutomationDirect) asked a question.
Do-More Rounding of Real Numbers
Created Date: July 20,2015
Created By: Dean
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Is there a better way to do this?
Created Date: July 20,2015
Created by: bcarlton
It seems easier to multiply by 10, truncate, then divide by 10.
Created Date: July 20,2015
Created by: Dean
Do you mean truncate instead of round for result R4? This wouldn't properly handle fractions 0.500 or greater. Or am I misunderstanding you?
Created Date: July 20,2015
Created by: bcarlton
Ok how about
It seems easier to multiply by 10, round, (truncate - I guess not needed), then divide by 10.
Created Date: July 20,2015
Created by: Do-more PE
Like Bernie said, it can all go in one expression. R2 = ROUND(R1 * 10) / 10
Created Date: July 20,2015
Created by: Dean
Okay I get it now. Thanks to both of you.
Created Date: July 20,2015
Created by: bcarlton
Do-More 1.41 using the Simulator
When I place
ROUND(R1 * 10) / 10
In a MATH instruction I get an answer for the equivalent of
ROUND((R1 * 10) / 10 ) (In other words - ROUND(R1) )
If I try to place parentheses like this to force 'multiply ' - 'ROUND ' - 'divide '
(ROUND(R1 * 10)) / 10
it deletes them and goes back to
ROUND(R1 * 10) / 10
I ended up having to break it into separate MATH blocks to get it right.
Created Date: July 20,2015
Created by: Do-more PE
Interesting. I'll pass that along to HOST to see what they have to say about it.
Created Date: July 20,2015
Created by: bcarlton
Yup - that does seem to do it. It's strange though, the 'R ' should have clued in the compiler that 'Real ' math was involved.
Created Date: July 20,2015
Created by: BobO
Please tell me what you are getting that is inconsistent with what you expect.
Edit: ROUND returns an integer...
Created Date: July 20,2015
Created by: bcarlton
The original poster wanted to round a Real to the first decimal position.
I suggested a 'times ten ' - 'ROUND ' - 'divide by ten ' sequence. I did it up in Do-more 1.41 with the simulator using 3 MATH instructions to verify.
Do-more PE suggested 1 MATH instruction using ROUND(R1 * 10) / 10 as the expression.
I tried that but only got a rounding to the lowest integer position.
Mike Nash suggested replacing 10 with 10.0 in the expression in the single MATH instruction.
I tried that and it worked.