CoCoA » CoCoALib

25 Jun 2015

18:40 Support #739: Move code in examples into namespace CoCoA

JAA has done @ex-[A-D]@
JAA has done @ex-[E-M]@ John Abbott

15:32 Support #739 (Closed): Move code in examples into namespace CoCoA

Following the change made to test files; move all code (except @main@) into @namespace CoCoA@.
This should keep th... John Abbott

18:12 Design #619 (Closed): Modulus (for CRTMill) ambiguous

Added example and test (actually they are the same).
Checked in. Closing!
John Abbott

17:27 Feature #721: CheckForInterrupt: string arg to specify where it was called?

I have checked in the current version (whose ctor requires a string). Waiting for Anna to check it.
At the moment... John Abbott

17:23 Feature #738: Extend homomorphism to polynomial ring

Anna, John and Renzo agree that cases (1) and (2) in comment 1 are OK, and that the others are best handled by constr... John Abbott

15:48 Feature #738: Extend homomorphism to polynomial ring

Here is the original situation where the problem arose. I Have some polynomials with complex coeffs (in @QQ[i]@) and... John Abbott

15:28 Feature #738 (In Progress): Extend homomorphism to polynomial ring

I don't like automatic choices: look at these examples... Anna Maria Bigatti

14:48 Feature #738: Extend homomorphism to polynomial ring

What precisely are the semantics? When can the function be called?
Various cases to consider:
# given @phi: R --> R@... John Abbott

14:41 Feature #738 (In Progress): Extend homomorphism to polynomial ring

It might be nice to have a simple/convenient/compact way of extending "coefficient homomorphisms" to polynomial rings... John Abbott

17:15 Design #642 (Closed): Move code in test file into namespace CoCoA

No problems encountered over the last month -- closing!
John Abbott

16:24 Feature #740: Addition of sparse (multivariate) polynomials

I computed @(1+x+y+z)^99@ using CoCoA and Singular on my machine. CoCoA took about 8s, singular took about 5s :-( John Abbott

16:23 Feature #740 (New): Addition of sparse (multivariate) polynomials

Singular computes the length of the sum of two polynomials as part of the main result. We should do something simila... John Abbott

15:34 Bug #736 (Resolved): QuotientRing: is it correct to prohibit quotient by ideal(1)?

done: added IsOne(IDEAL) Anna Maria Bigatti

14:30 Bug #736 (In Progress): QuotientRing: is it correct to prohibit quotient by ideal(1)?

John Abbott wrote:
> * @if 1 isin I then ....@
> * @if IsOne(I) then ....@
the first already works. The second ... Anna Maria Bigatti

12:52 Bug #736: QuotientRing: is it correct to prohibit quotient by ideal(1)?

Robbiano confirms that it is best to avoid the null ring (which has surprising properties such as @1 = 0@).
In thi... John Abbott

15:27 Bug #631: Ambiguous: rank for matrix (in ex-matrix1.C)

JAA notes that now we're planning to move all test/example code into @namespace CoCoA@ the problem of ambiguity (in n... John Abbott

15:16 Bug #666 (Closed): RatReconstructByLattice fails in some simple cases

Modified C5 doc too.
John Abbott

21 Jun 2015

21:09 Bug #736: QuotientRing: is it correct to prohibit quotient by ideal(1)?

The problem arose while doing some computations for Ulrich where it was known/expected that some ideals would be @ide... John Abbott

21:06 Bug #736 (Closed): QuotientRing: is it correct to prohibit quotient by ideal(1)?

The quotient ring @R/I@ where @I=ideal(1)@ gives the trivial ring.
Currently the quotienting operation gives a spe... John Abbott

16 Jun 2015

08:25 Feature #665: Integrate Janet/Pommaret basis code

At the moment the UIBC uses only the standard algorithm to compute a Janet basis @TQBlockLow@. But it should be possi... Mario Albert

12 Jun 2015

12:03 Feature #664: Impl small non-prime finite fields (using logs)

Now I have a (partly?) working CoCoALib ring which wraps my previous code.
John Abbott

11 Jun 2015

20:06 Feature #728: Noncommutative algebra "of solvable type"

As I am sitting in a delayed train with too much time at hand, some further comments:
1.) The "book" by Levandovsk... Werner M Seiler

15:27 Feature #728: Noncommutative algebra "of solvable type"

Going to a seminar here about G-bases in PBW algebras :-)
*NOTE* the seminar was OK. The student pointed out that (... John Abbott

11:43 Feature #728 (In Progress): Noncommutative algebra "of solvable type"

Yes, we should get the old @RingWeyl@ code working again -- my guess is that there is little to do.
We should find... John Abbott

11:30 Feature #728: Noncommutative algebra "of solvable type"

We have already done most of these considerations for RingWeyl (except for the coefficient rule).
.. and we also had... Anna Maria Bigatti

11:14 Feature #728: Noncommutative algebra "of solvable type"

Werner pointed out that a simplistic implementation is likely to be terribly slow (though perhaps "obviously correct"... John Abbott

19:00 Feature #735 (Resolved): Convert a PPMonoidElem to RingElem with coefficient one

done, checked in.
So far I modified only the files in AlgebraicCore Anna Maria Bigatti

11:46 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

OK, do it! Including @monomial(P,expv)@.
Don't forget documentation, examples and tests!
John Abbott

11:24 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

My preference (by far) goes to @monomial(P, pp)@
I have already implemented and all tests pass.
Should I also do @m... Anna Maria Bigatti

11:04 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

I point out that assignment to @RingElem@ can perform some type changes. Should we allow assignment to a @RingElem@ ... John Abbott

11:00 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

I do agree that, without familiarity with the function, upon reading @monomial(P,1,pp)@ my first thought would be "Wh... John Abbott

10:46 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

I didn't know that @monomial(P, 1, pp)@ works as expected.
But I think for the _normal_ user who wants to use a @PP... Mario Albert

10:41 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

I am a little uncertain about the proposal. @monomial(P,pp)@ gains little over @monomial(P,1,pp)@.
Is it worth cr... John Abbott

08:56 Feature #735: Convert a PPMonoidElem to RingElem with coefficient one

Should we do the same for @monomial(P, expv)@?
I cannot see any ambiguity.
*REPLY* (JAA) if we have @monomial(P,PP)@... Anna Maria Bigatti

08:41 Feature #735 (In Progress): Convert a PPMonoidElem to RingElem with coefficient one

That seems very reasonable: I had a look at the code and, indeed, most of the times @monomial@ is called the coeffici... Anna Maria Bigatti

08:31 Feature #735 (Closed): Convert a PPMonoidElem to RingElem with coefficient one

Let @pp@ be a @PPMonoidElem@ of the @PPMonoid@ @PPM@. Let @P@ be a @SparsePolyRing@ with @PPM@ as @PPMonoid@.
Severa... Mario Albert

15:26 Feature #664 (In Progress): Impl small non-prime finite fields (using logs)

JAA has implemented a first prototype (following the model @RingFpImpl@ and @SmallFpImpl@). The computational part u... John Abbott

14:58 Feature #386: add resolution data type

Hans says that singular uses more or less the design we are considering; apparently in some cases they store two reso... John Abbott

11:57 Feature #386: add resolution data type

One possibility might be to have a "module view" much like @MatrixView@, but I'm far from certain whether such a thin... John Abbott

11:43 Feature #386: add resolution data type

> Since the C++ types of the input are different it seems simplest to have different classes for each case. Each cla... Anna Maria Bigatti

08:24 Feature #665: Integrate Janet/Pommaret basis code

In the following I try to explain how I integrated the JBMill/PBMill into @SparsePolyRing::IdealImpl@:
h3. UIBC
... Mario Albert

10 Jun 2015

17:12 Feature #728: Noncommutative algebra "of solvable type"

For starters Ore algebra as a simple case of polynomial algebras of solvable type should be enough. Their main advant... Werner M Seiler

12:55 Feature #728: Noncommutative algebra "of solvable type"

I made a slight mistake in the original description. It should have been:
* @x[i]*x[j] = q*x[j]*x[i] + tail@ where @... John Abbott

14:24 Slug #725: Example database: Slow ideal equality test

John Abbott wrote:
> In the specific example of this issue there are 36 indets (all used), 15 polynomials, and @dim(... Anna Maria Bigatti

13:41 Feature #386 (In Progress): add resolution data type

Mario and I have discussed some possible designs; neither of us has much experience with resolutions, so it is possib... John Abbott

13:19 Feature #729 (In Progress): Betti numbers, betti diagram

Mario suggested that the internal representation should be @vector< map<degree, long> >@.
The resolution is a list... John Abbott

11:30 Feature #730: Stats in GBMill (GReductor)

I suppose Mario ought to write about this. He has followed my design suggestion, and seems to be happy with it. If ... John Abbott

11:24 Feature #730: Stats in GBMill (GReductor)

Mario asked about gathering stats for his involutive basis code.
I suggested using a @struct@ to keep all the stats ... John Abbott

11:18 Feature #730 (Closed): Stats in GBMill (GReductor)

There is already some implementation for gathering stats in G-basis computation.
Review it!
Perhaps separate st... John Abbott

08 Jun 2015

22:27 Feature #728: Noncommutative algebra "of solvable type"

Sounds like a generalisation of RingWeyl.
... Werner, are you willing to test it out? ;-)
I was thinking of porti... Anna Maria Bigatti

18:45 Feature #728 (In Progress): Noncommutative algebra "of solvable type"

Werner asked about the possibility of having non-commutative algebras of solvable type. They are nice enough that Bu... John Abbott

18:52 Feature #729: Betti numbers, betti diagram

Mario points out that for a non-graded case we will also need a datastructure.
*UPDATE* (20150608) Mario thinks it is... John Abbott

18:50 Feature #729 (In Progress): Betti numbers, betti diagram

Design a good data structure for storing Betti numbers (also for multigraded case).
John Abbott

11:09 Feature #718: Insert calls to CheckForInterrupt

Mario asked about the possible run-time cost of calling @CheckForInterrupt@.
Currently it may be needlessly expensiv... John Abbott

07 Jun 2015

12:46 Slug #725: Example database: Slow ideal equality test

In the specific example of this issue there are 36 indets (all used), 15 polynomials, and @dim(P/I)@ gives 21. Isn't... John Abbott

06 Jun 2015

22:49 Slug #725: Example database: Slow ideal equality test

For completeness here is the list of generators in @QQ[x[1..6,1..6]]@ ... John Abbott

22:46 Slug #725: Example database: Slow ideal equality test

Anna, you are right (in principle). In practice, I think almost the whole time is spent computing a G-basis (rather ... John Abbott

21:17 Slug #725: Example database: Slow ideal equality test

Instead of checking equality you should just check whether g_j is in the ideal generated by the others. However, thi... Anna Maria Bigatti

20:32 Slug #725: Example database: Slow ideal equality test

It has finally finished:... John Abbott

14:25 Slug #725: Example database: Slow ideal equality test

Progress...... John Abbott

13:19 Slug #725: Example database: Slow ideal equality test

Re-running the program (over @QQ@) I get the following output (still incomplete):... John Abbott

13:14 Slug #725 (New): Example database: Slow ideal equality test

This is probably not important, but I wanted to record this example which seems to be unexpectedly slow -- it might b... John Abbott

01 Jun 2015

22:31 Slug #722 (In Progress): valuation slow for large inputs

I have implemented a version which divides repreatedly by the largest power of the prime which fits into @unsigned lo... John Abbott

10:39 Slug #722: valuation slow for large inputs

Probably @QuoRem@ is a more sensible choice than @gcd@.
John Abbott

31 May 2015

11:58 Slug #722: valuation slow for large inputs

Source code is in @NumTheory.C@.
It is just a very simple loop. Presumably I could test divisibility by a small pow... John Abbott

11:56 Slug #722 (Closed): valuation slow for large inputs

I tried @valuation(5,factorial(1000000))@ and it took too long.
Make @valuation@ faster if the prime is small (and... John Abbott

30 May 2015

14:52 Feature #721: CheckForInterrupt: string arg to specify where it was called?

I have implemented my suggestion in note 1.
It occurred to me that if we do allow a string as arg (to where @Check... John Abbott

10:01 Feature #721 (In Progress): CheckForInterrupt: string arg to specify where it was called?

I prefer that the exception thrown is not of the same type as a normal @CoCoA_ERROR@ because the reasons behind the e... John Abbott

10:22 Feature #385: Design new errors using inheritance

I think it may be a cleaner design to use (impose) the convention that all exceptions CoCoALib are derived from a sin... John Abbott

29 May 2015

17:20 Feature #721: CheckForInterrupt: string arg to specify where it was called?

In fact I was suggesting something else: @CheckInterrupt@ throws something which is not a CoCoA_ERROR, so cocoa-5 doe... Anna Maria Bigatti

16:19 Feature #721: CheckForInterrupt: string arg to specify where it was called?

It looks to be almost trivial to add @CheckForInterrupt(const char*)@ and @CheckForInterrupt(const std::string&)@.
... John Abbott

16:16 Feature #721 (Closed): CheckForInterrupt: string arg to specify where it was called?

Anna indirectly suggested that it might be nice to have an optional arg to @CheckForInterrupt@ which takes a string i... John Abbott

12:03 Feature #718 (In Progress): Insert calls to CheckForInterrupt

Nice! I added it into @TmpGReductor.C@ (I was actually doing something else with very slow GB ;-) )... Anna Maria Bigatti