Re: Adds longas, maximas and non-standard tweaks to MultiMeasureRest (issue4536068)

[dak]

http://codereview.appspot.com/4536068/diff/30001/lily/multi-measure-rest.cc
File lily/multi-measure-rest.cc (right):

http://codereview.appspot.com/4536068/diff/30001/lily/multi-measure-rest.cc#newcode131
lily/multi-measure-rest.cc:131: int measure_duration_log = int (ceil
(duration_log));
On 2011/07/27 04:13:48, Keith wrote:
> To me, having done numerical work, the chain of functions you use,
int( ceil(
> -log2(x))), is easily recognizable as "find the smallest n so that 1 /
2^n <=
> x".

> While log2 is inexact, the results when x is a power of 2 are exact
> (IEEE-compliant floating-point represents integers and integer powers
of 2
> exactly) so reliably 3/4 and 2/4 both come out 1 (half/minim rest).

log2 is a transcedental operation, it is not guaranteed to be exact.
logb would be (it just returns the exponent from the floating point
representation).

Anyway, it seems like log2 is not universally available, so we should
avoid it.  The same is likely true for logb.

http://codereview.appspot.com/4536068/diff/37002/lily/multi-measure-rest.cc
File lily/multi-measure-rest.cc (right):

http://codereview.appspot.com/4536068/diff/37002/lily/multi-measure-rest.cc#newcode241
lily/multi-measure-rest.cc:241: length = (2 << -i) / 2;
The division by 2 changes the result.  Not that I understand too well
what it is supposed to be doing.

http://codereview.appspot.com/4536068/