I'm using an expression object here to attempt a very simple task, to multiply a variable by a fractional ratio. In the process, I have run into this trouble:

I create a number object and feed it into [expr $f1*(25/24)], but I only receive my variable back to me as output (as if it was merely being multiplied by 1, rather than by the fraction). So I do some testing, and find what does and does not seem to work:

My question is: Why?

Why is it that { 25 -> [expr $f1/24] => 1.041 } works but [expr 25/24] does not and returns 1. It seems like the expression object is rounding to the nearest integer, but that does not make sense.

1 -> [expr (25*$f1)/24] => 1.041 Works.
1 -> [expr (25/24)*$f1] => 1 does Not.

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I know it's a dull question, so I appreciate you in helping me to understand. I want to understand, so that I can avoid the frustration later.

PEACE

yeah, that does seem like a bug.

http://puredata.info/docs/faq/how-do-i-report-a-bug

expr is doing integer arithmetic with your constants, so 25/24 rounds off to 1.
When you pass in the 25, it is a float, so the computation is done floating point, as you want.

Change it to [expr $f1 * 25.0/24] and it will evaluate the fraction in floating point.

you could actually get away with 25./24

it would probably be better if expr converted everything to floats because you can't pass in an int anyway?
dunno how much work it would entail, expr's source code is kinda... extensive
edit: I opened a feature request http://sourceforge.net/p/pure-data/feature-requests/138/