[Axiom-developer] Re: Savannah patches

[Martin Rubey]

Dear Bill,

Bill Page writes:
 > #2074:  Bug #4733 (rounding of negative numbers) [AS]
 > #3089:  bug #6357 sqrt(-1/abs(x))-1/sqrt(-abs(x))=>0 [A]
 > #3121:  [bugs #9057] product over product or sum fail [A]
 > #3349:  bug #10312 Problems raising a UTS to a negative integer power  [A]

What does [A] and [AS] mean?
 
 > I do have some questions about the status of some others. From
 > the comments it is not clear to me that the proposed patches are
 > complete:
 > 
 > #3127:  bug #9297 -- output misses parenthesis in COMBF [A]

the patch does the straightforward thing: it always adds parentheses around a
sum and a product. In certain cases, the parentheses might not be strictly
necessary, but with the patch the output is always mathematically correct. I'd
say that it could be a *future* project to improve output.

 > #3148:  bug #9216 differentiating sums with respect to a bound is wrong [A]

in my opinion correct beyond doubt.

 > #3161:  any? and every? should exit when the result is clear [A]

I don't have the time to look it up right now, whether the "mixed" behaviou
TREE would vanish with this patch or not. In any case, this "bug" will never
produce mathematically incorrect results. It will only waste cpu cycles. In
fact, I included the comment regarding TREE only to document that if there
would be code that depends on the "evaluate all" code, it wouldn't work with
TREE anyway, so it would be broken already. Bottom line: no danger. 

 > Also, you submitted these as direct patches to the .spad files.  Really you
 > should be patching the .spad.pamphlet files.

Yes. 100% correct.

 > And it would be **very desirable** if in the future you could also include
 > some new documentation in the .spad.pamphlet file describing the problem and
 > the nature of the change. Most of the documentation is still missing for the
 > algebra files, so if you learn something new while analysing a problem, it
 > would be great to capture this and add and/or revise the documentation for
 > future generations.

Absolutely right. I promise to deliver documentation before 3.0 i.e., before
February. (In fact, the reason was that I was waiting for pamphlet support on
mathaction... I had the feeling it would be easier to document then.)

 > This one seems to have been anonymously submitted, but it looks ok to me.
 > 
 > #3311:  bug #10069 overview: cot(0.0), csc(0.0), asec(0.0),
 > acsc(0.0),asech(0.0),acsch(0.0),cot(0.0),coth(0.0),acoth(0.0) [A]
 > 
I didn't look at that one.

Thanks for patching!

Martin