calc-cbs-params: fix off-by-one on locredit calculation #37
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The locredit parameter is a rounded up integer from a floating-point division. Unfortunately, locredit is a negative number (as it is derived from sendslope), and the rounding up python function employed (math.ceil()) provides the relative (not absolute) rounded up value. Thus, math.ceil(-4.2) is -4 and not -5. Use math.floor() for this specific case. Before this patch: $ ./calc-cbs-params.py --stream class=a,transport=avtp-aaf,rate=8000,psize=384 Class A: idleslope 28800 sendslope -971200 hicredit 45 locredit -437 (...) After this patch: $ ./calc-cbs-params.py --stream class=a,transport=avtp-aaf,rate=8000,psize=384 Class A: idleslope 28800 sendslope -971200 hicredit 45 locredit -438 (...) Signed-off-by: Rodrigo Cataldo <[email protected]>
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Hello everyone,
i think i found an off-by-one issue on locredit calculation, assuming that the intent of
ceilwas to always round up.Let me know if you all agree.
If I am wrong, i still think we should add a comment since
ceil()may not behave as "expected".The locredit parameter is a rounded up integer from a floating-point division. Unfortunately, locredit is a negative number (as it is derived from sendslope), and the rounding up python function employed (math.ceil()) provides the relative (not absolute) rounded up value.
Thus, math.ceil(-4.2) is -4 and not -5.
Use math.floor() for this specific case.
Before this patch:
$ ./calc-cbs-params.py --stream class=a,transport=avtp-aaf,rate=8000,psize=384
Class A: idleslope 28800 sendslope -971200 hicredit 45 locredit -437
(...)
After this patch:
$ ./calc-cbs-params.py --stream class=a,transport=avtp-aaf,rate=8000,psize=384
Class A: idleslope 28800 sendslope -971200 hicredit 45 locredit -438
(...)