CoCoA

25 May 2016

17:01 CoCoALib Slug #881: ReadExpr is too slow on large polys

Using the profiler on a linux box I noticed that @DistrMPolyInlPP::myPushFront@ was using surprisingly much time. I ... John Abbott

16:57 CoCoALib Feature #885: IsIrred3: fast 3-way irred test (returning bool3)

The idea of @IsIrred3@ was created because of some computations Mario needed to do with multivariate polynomials, so ... John Abbott

11:13 CoCoALib Feature #885 (In Progress): IsIrred3: fast 3-way irred test (returning bool3)

Some questions:
* *(A)* what should the function be called? Is @IsIrred3@ a reasonable name?
* *(B)* what should t... John Abbott

16:49 CoCoALib Design #846: IsIrred: correct design?

The simplest design is to make @IsIrred@ call @IsIrred3@; this somehow equates calling @IsIrred3@ to handling the tri... John Abbott

13:43 CoCoALib Design #846 (In Progress): IsIrred: correct design?

I think a first version of @IsIrred@ should give error if the ring is a field; if it turns out that this is inconveni... John Abbott

24 May 2016

17:27 CoCoALib Feature #885 (In Progress): IsIrred3: fast 3-way irred test (returning bool3)

Implement an irreducibility test @IsIrred3@ which is guaranteed to be fast, but returns a @bool3@.
John Abbott

15:25 CoCoALib Slug #884: DistrMPolyInlPP::myPushFront and DistrMPolyInlPP::myPushBack inefficient if arg is a PP

I wrote a special reading fn for polynomials (using a "private" linearization). It was not as fast as I hoped, and p... John Abbott

15:20 CoCoALib Slug #884 (New): DistrMPolyInlPP::myPushFront and DistrMPolyInlPP::myPushBack inefficient if arg is a PP

In the class @DistrMPolyInlPP@ the mem fns @myPushFront@ and myPushBack@ can accept raw coeff and raw pp, *BUT* the i... John Abbott

18 May 2016

13:44 CoCoALib Slug #881 (Resolved): ReadExpr is too slow on large polys

I have modified @ReadExprInSparsePolyRing@ so that sums of terms are handled specially: the terms are simply appended... John Abbott

11 May 2016

14:48 CoCoALib Slug #881: ReadExpr is too slow on large polys

I reran the test to read Mario's polynomial: now it takes about 0.4s (with the "wrong" term-ordering), and about 0.25... John Abbott

14:32 CoCoALib Slug #881: ReadExpr is too slow on large polys

I have now finished the main changes to @DistrMPolyInlPP@, and especially @myAddClear@. Time to read a correctly ord... John Abbott

12:09 CoCoALib Slug #881: ReadExpr is too slow on large polys

I wrote a very hacked version which uses @PushBack@, and it went considerably faster (but it also gave SEGV on some e... John Abbott

10 May 2016

16:41 CoCoA-5 Feature #883: gin: return/print a suitable change of variables

How about a new fn which computes both gin and a "simple" suitable transformation?
Or maybe a fn which takes an idea... John Abbott

16:30 CoCoA-5 Feature #883: gin: return/print a suitable change of variables

John Abbott wrote:
> Werner also asked whether the transformation used is triangular or square.
triangular (auxil... Anna Maria Bigatti

15:28 CoCoA-5 Feature #883 (In Progress): gin: return/print a suitable change of variables

Werner also asked whether the transformation used is triangular or square.
It might be nice to have the option to ... John Abbott

13:54 CoCoA-5 Feature #883: gin: return/print a suitable change of variables

John Abbott wrote:
> Werner Seiler asks whether it would be possible to make @gin@ also produce a "good" linear chan... Anna Maria Bigatti

11:11 CoCoA-5 Feature #883 (Closed): gin: return/print a suitable change of variables

Werner Seiler asks whether it would be possible to make @gin@ also produce a "good" linear change of variables (ideal... John Abbott

16:36 CoCoALib Slug #881: ReadExpr is too slow on large polys

I have already implemented (and checked in) a version which uses geobuckets when the ring is a sparsepolyring.
Mar... John Abbott

16:19 CoCoALib Slug #881: ReadExpr is too slow on large polys

John Abbott wrote:
> I have done a quick profile of the current version of the code (using the _ad hoc_ impl with @s... Anna Maria Bigatti

15:33 CoCoALib Slug #881 (In Progress): ReadExpr is too slow on large polys

I have done a quick profile of the current version of the code (using the _ad hoc_ impl with @std::map@). Now most (... John Abbott

13:25 CoCoALib Slug #881: ReadExpr is too slow on large polys

I have hacked the @ReadExpr@ code so that it produces a table of symbols (of type @std::map@).
This improved the rea... John Abbott

14:02 CoCoA-5 Feature #877: Easier syntax to make a PRINCIPAL ideal?

John Abbott wrote:
> Perhaps the error message should say which signatures @ideal@ does offer?
Yes, I like that (... Anna Maria Bigatti

09 May 2016

22:10 CoCoALib Slug #882: Impl faster multiplication for DUP (dense univariate polys)

I also tried implementing a method which uses fast integer multiplication in GMP.
Evaluate both polys at 1000000 (... John Abbott

22:07 CoCoALib Slug #882: Impl faster multiplication for DUP (dense univariate polys)

I made a very _ad hoc_ impl of karatsuba when I was in Osnabrueck as I wanted to get an idea of when cross-over might... John Abbott

22:05 CoCoALib Slug #882 (New): Impl faster multiplication for DUP (dense univariate polys)

Christof wanted faster multiplication for DUPs.
He suggested implementing karatsuba's method. John Abbott

21:49 CoCoALib Slug #881: ReadExpr is too slow on large polys

I did a quick test:... John Abbott

21:23 CoCoALib Slug #881: ReadExpr is too slow on large polys

Since my "stupid" MacBook cannot profile, I can only guess that reading a symbol is probably quite costly (see line 7... John Abbott

21:13 CoCoALib Slug #881: ReadExpr is too slow on large polys

I have implemented a first improvement by implementing a new fn @ReadExprInSparsePolyRing@ which uses geobuckets to s... John Abbott

21:10 CoCoALib Slug #881 (Closed): ReadExpr is too slow on large polys

Recently Mario has passed me some large polys in their printed form (_i.e._ sum of terms). Reading them by pasting t... John Abbott

20:51 CoCoALib Slug #874: factor: too slow on largish multivariate poly

I have implemented a prototype "heuristic" irred test which returns a @bool3@.
First it checks for a non-triv comm... John Abbott

15:56 CoCoA-5 Bug #880 (Closed): subst should check that indet is in same ring as 1st arg, but does not.

@subst@ should check that indet is in same ring as 1st arg, but does not.
Here is an example:... John Abbott

15:30 CoCoA-5 Support #879: LOGAR: make CoCoA-5 easier to use

At some point I triggered a bug in CoCoA-5. I was trying to use @subst@ somehow (to replace @a[6]@ by zero); perhaps... John Abbott

15:25 CoCoA-5 Support #879: LOGAR: make CoCoA-5 easier to use

Sandro then wanted to compute the expressions for the coordinates of the intersection points of the line and the elli... John Abbott

15:16 CoCoA-5 Support #879: LOGAR: make CoCoA-5 easier to use

@cond1@ corresponds to the condition that the ellipse passes through the origin.
It simplifies to @a[6]=0@.
We woul... John Abbott

15:10 CoCoA-5 Support #879: LOGAR: make CoCoA-5 easier to use

... John Abbott

15:05 CoCoA-5 Support #879 (New): LOGAR: make CoCoA-5 easier to use

In early May 2016 I met (Sandro) Logar at the Normaliz workshop in Osnabrueck.
I wanted to persuade him to use CoCoA... John Abbott

14:51 CoCoA-5 Feature #877 (In Progress): Easier syntax to make a PRINCIPAL ideal?

Now I recall what I tried: @ideal(R,x)@ does not work; it says it wants a list instead of a RINGELEM.
Are there an... John Abbott

11:43 CoCoA-5 Feature #877: Easier syntax to make a PRINCIPAL ideal?

It is already done, both in CoCoA-5 and CoCoALib (in CoCoALib up to 4 generators). Anna Maria Bigatti

11:11 CoCoA-5 Feature #877 (Closed): Easier syntax to make a PRINCIPAL ideal?

Currently the way to make a principal ideal is not so natural: the generator must be put into a list.
Are there an... John Abbott

11:29 CoCoA-5 Bug #878: RingElem applied to a symbol (repr as a string)

Personally I find the situation described quite confusing.
It is not clear to me why @ReadExpr@ is not already inc... John Abbott

11:25 CoCoA-5 Bug #878 (Closed): RingElem applied to a symbol (repr as a string)

The current design for converting a symbol (repr as a string) into a RINGELEM is inconvenient.
I wanted to do this... John Abbott

07 May 2016

13:59 CoCoA-5 Feature #876: subst: allowed also for indets in the coeff ring

Here is an example I was trying with Sandro Logar... John Abbott

13:57 CoCoA-5 Feature #876 (New): subst: allowed also for indets in the coeff ring

Suppose we have a poly ring of the form @QQ(a,b)[x,y]@ and I want to substitute @b=a+1@.
Currently @subst@ refuses b... John Abbott

06 May 2016

16:43 CoCoALib Slug #866: implicit, ImplicitHypersurface: improve output verification

I have not yet had time to look at your horner code. Anyway, I would expect it work fairly well provided the "variab... John Abbott

03 May 2016

17:02 CoCoA-5 Slug #875: Interpreter is too slow reading a big polynomial

I have tried doing some profiling. The interpreter takes quadratic time (in the number of terms) to read a polynomia... John Abbott

14:00 CoCoA-5 Slug #875 (In Progress): Interpreter is too slow reading a big polynomial

I'm trying to read a large polynomial: about 6Mbytes, about 127000 terms in 100 indets, coefficients in @QQ@ (but all... John Abbott

13:14 CoCoALib Slug #874: factor: too slow on largish multivariate poly

Mario has just sent me an even bigger polynomial to try: 100 indets, about 127000 terms, total degree 9.
He also m... John Abbott

10:50 CoCoALib Slug #874 (In Progress): factor: too slow on largish multivariate poly

Computing all contents takes about 44s; and computing contents wrt all indets which appear just linearly takes about ... John Abbott

10:42 CoCoALib Slug #874: factor: too slow on largish multivariate poly

Mario has given me an example poly. The poly ring has 84 indets; the poly itself uses 69 indets, and has about 6800 ... John Abbott

10:37 CoCoALib Slug #874 (In Progress): factor: too slow on largish multivariate poly

Mario generates lots of multivariate polys (over @QQ@); most of them are irreducible. He reports that factorization ... John Abbott

10:34 CoCoALib Support #861 (In Progress): Janet basis code: TmpJB files give some problems with C++11 (using CLANG/LLVM)

Mario has given me an updated version of his code. He has used the @__cplusplus@ preprocessor variable to have code ... John Abbott

29 Apr 2016

22:00 CoCoALib Feature #873: bool3: add some logical operations?

(Maybe this is what you had in mind from the beginning)
I think the only safe definition for @and3@ is the @and@ bet... Anna Maria Bigatti

19:21 CoCoALib Feature #873: bool3: add some logical operations?

The "monomial generators" case is easy.
The "is a monomial ideal" is hard in any case: even if both ideals are not m... John Abbott

18:53 CoCoALib Feature #873: bool3: add some logical operations?

I expect in some cases we want
uncertain3 and false3 = false3 (sum of ideals has monomial generators)
and other t... Anna Maria Bigatti

18:15 CoCoALib Feature #873 (In Progress): bool3: add some logical operations?

It would not be harmful to your code if @bool3@ offered the functions, but you may be right that it would not simplif... John Abbott

28 Apr 2016

10:45 CoCoALib Feature #873: bool3: add some logical operations?

I'm against this idea. Indeed it might be handy, but dangerous as well: while working on fixing a bug on the bool3 f... Anna Maria Bigatti

27 Apr 2016

19:05 CoCoA-5 Bug #870: GBasis of product of ideals is wrong (Vadim Tropashko) --> I.myReset()

I have added a new CoCoALib test (@test-bug6.C@) which tests for this specific problem.
It should later be expande... John Abbott

08:57 CoCoA-5 Bug #870: GBasis of product of ideals is wrong (Vadim Tropashko) --> I.myReset()

John Abbott wrote:
> I suggest that Anna try to fix the functions already in @SparsePolyRing.C@.
done! (cvs-ing)
... Anna Maria Bigatti

18:49 CoCoALib Feature #873: bool3: add some logical operations?

BOOST also offers a "not" operation. It would be trivial to implement @not3@ (giving value 1 - arg).
If we do off... John Abbott

18:45 CoCoALib Feature #873: bool3: add some logical operations?

Part of the motivation comes from Anna's rectification of code for ideal arithmetic (see issue #870).
For example ... John Abbott

18:42 CoCoALib Feature #873: bool3: add some logical operations?

I suggest adding the following two operations:
* *and* which is equivalent to "minimum"
* *or* which is equivalent... John Abbott

18:37 CoCoALib Feature #873 (In Progress): bool3: add some logical operations?

Currently there are no logical operations on @bool3@ values.
Discuss whether it may be helpful to include some sim... John Abbott