newRPL  build 1255 released! [updated to 1299]

01112019, 04:16 PM
Post: #355




RE: newRPL  build 1089 released! [update:build 1127]
(01112019 03:05 AM)The Shadow Wrote: I'm trying to come up with situations in which one would define conditions on things other than numeric values, and so far I'm coming up blank. I can't come up with an example either, but also remember, many numeric expressions can't be computed exactly with >NUM either, imagine a rule to replace exact known values for SIN(), we need that argument to be expressed as a fraction of pi, which needs to remain symbolic to be exact. You could write SIN(.NN*pi/2) in the rule itself, but that wouldn't match SIN(pipi/2) at first sight. Of course, you could use RULEAPPLY, which would fail at first, then do autosimplification (turning into SIN(pi/2)), then will try again and would match, but not with RULEAPPLY1 which would fail initially and that's the end of it. Moving that to a condition by writing SIN(.NN) :> ...  FP(2*.NN/pi)==0 you need to first simplify the condition symbolically so if .NN has pi as a factor it would cancel out, then numerically to check that the result is an integer without precision loss. 

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