CoCoA

24 May 2019

17:43 CoCoA-5 Bug #1288: len for RINGELEM ?!?

The source code for the function @len@ is in file @BuiltinFunctions-CoCoALib.C@ around line 100.
The code recognis... John Abbott

16:25 CoCoA-5 Bug #1288: len for RINGELEM ?!?

The manual entry for @len@ looks a bit strange, and is hard to read. It says the fn signature is... John Abbott

16:22 CoCoA-5 Bug #1288 (Closed): len for RINGELEM ?!?

I was surprised to discover that @len@ can be applied to a @RINGELEM@.... John Abbott

04:18 CoCoA-5 Feature #1272: Groebner Bases over ZZ

We also wrote a prototype implementation of GBasis over ZZ. In particular we focused on minimal strong GBasis. Maybe ... Elisa Palezzato

23 May 2019

15:13 CoCoA-5 Support #1287 (In Progress): Better err mesg for easy typo in ring definition

The relevant source code is in @Parser.C@ around line 360 in the function @parseUseStatement@.
I think it may be ... John Abbott

12:16 CoCoA-5 Support #1287 (Closed): Better err mesg for easy typo in ring definition

Consider this excerpt:... John Abbott

11:53 CoCoA-5 Feature #1285: New Fn: make a homogeneous list of ringelem

What exactly should the function do? What should it be called?
* *(A)* simplest is to accept @RINGELEM@ and @INT@... John Abbott

11:30 CoCoA-5 Feature #1285 (New): New Fn: make a homogeneous list of ringelem

Proposal: create a new function which takes a ring and a list, and returns a list of RINGELEM belonging to the speci... John Abbott

11:48 CoCoA-5 Bug #1286: Website: trouble with the world map

I'm very unhappy about the CPU "burning" (it might well be a Google revenge tactic).
Also after visiting the page ... John Abbott

11:46 CoCoA-5 Bug #1286 (Closed): Website: trouble with the world map

The world map showing where visitors to the CoCoA website come from causes trouble in "private mode" in Firefox:
* t... John Abbott

11:23 CoCoA-5 Design #1120: Web site

Should we close this? Ater all 5.2.4 has been released.
What about the problem with "forever loading"?
John Abbott

11:17 CoCoA-5 Feature #1272: Groebner Bases over ZZ

Florian Walsh (Passau) has an prototype implementation of GBasis over ZZ, currently as a package in CoCoA-5. He is w... John Abbott

22 May 2019

22:05 CoCoA-5 Slug #1284 (Resolved): CartesianProductList: too slow

I suspect that the main problem is that @append@ is terribly slow -- I'm pretty sure it makes needless copies.
Her... John Abbott

16:30 CoCoA-5 Slug #1284: CartesianProductList: too slow

@CartesianProductList@ is defined in @list.cpkg5@
Ange reported that @CartesianProductList@ is slow; maybe I had a... John Abbott

16:18 CoCoA-5 Slug #1284: CartesianProductList: too slow

The examples above are not tiny, but also not so large. The resulting lists contained 32768 elements, and each eleme... John Abbott

16:15 CoCoA-5 Slug #1284 (Closed): CartesianProductList: too slow

Cartesian product operator is much faster than @CartesianProductList@.
Example:... John Abbott

11 May 2019

21:57 CoCoALib Feature #1283: Printing for (prime) finite fields

Consider the following session:... John Abbott

21:53 CoCoALib Feature #1283 (Closed): Printing for (prime) finite fields

I have found a "useful" result in an old file.
Unfortunately the result contains printed forms of the RingHoms used ... John Abbott

20:47 CoCoA-5 Support #1006: External dependencies for building

I have just tried building CoCoA-5 on my old MacBook, and it failed because java is not installed.
* it is annoyin... John Abbott

05 May 2019

10:07 CoCoALib Feature #1282 (New): subresultant

A long time ago Ring Xiao sent an implementation of Ducos's subresultant chain algorithm.
Clean it, and incorporate ... John Abbott

04 May 2019

21:05 CoCoALib Bug #1281: Factor of multivariate sometimes prints ERROR

The simplest examples (with 3 terms) seem to be of deg 7 (none found in deg 6 or deg 5).... John Abbott

20:55 CoCoALib Bug #1281 (New): Factor of multivariate sometimes prints ERROR

Here is an example:... John Abbott

03 May 2019

20:36 CoCoALib Bug #1280: Determinant & Inverse of matrix over non integral domain

I'm now wondering what is the difference between @ConstMatrixViewBase::myDet@ and @DenseMatImpl::myDet@... John Abbott

16:35 CoCoALib Bug #1280: Determinant & Inverse of matrix over non integral domain

I'd like to rewrite @ConstMatrixViewBase::myDet@ so that it calls the "fast" impls for small matrices. How to do thi... John Abbott

15:59 CoCoALib Bug #1280 (In Progress): Determinant & Inverse of matrix over non integral domain

Some thoughts about computing the determinant.
There is special case code for:
* small matrices (up to 5x5 incl.)... John Abbott

13:57 CoCoALib Bug #1280: Determinant & Inverse of matrix over non integral domain

Here is a simple failing case:... John Abbott

13:51 CoCoALib Bug #1280 (In Progress): Determinant & Inverse of matrix over non integral domain

CoCoA gives unnecessary errors when computing det or inverse of a matrix over a non-integral domain.
Rectify! John Abbott

14:05 CoCoALib Support #1263: Tidy CoCoALib test directory

I have just checked that running *all* @test-bugNNN@ executables takes about 0.03s on my computer. Since these files... John Abbott

13:45 CoCoALib Feature #303: Rows and Columns of a matrix

I have now added @GetRow@, @GetCol@, @GetRows@ and @GetCols@ to @MatrixOps.txt@
Fixed a couple of minor bugs. Is ... John Abbott

13:24 CoCoALib Feature #303 (Resolved): Rows and Columns of a matrix

I have just implemented @GetRow@, @GetCol@, @GetRows@ and @GetCols@.
Perhaps the names are not ideal, but they are... John Abbott

11:47 CoCoALib Design #1279 (Closed): Tidy up code for matrix determinant

I recently encountered an unexpected error while trying to compute the determinant of a 2x2 matrix over @ZZ/(841)@ wh... John Abbott

11:42 CoCoALib Feature #1278 (New): Port old "clever" code for matrix determinant over ZZ to CoCoALib

In CoCoA-4 there was a "clever" implementation of matrix determinant(over ZZ) based on the paper with Bronstein and M... John Abbott

11:39 CoCoALib Feature #11 (Closed): Bareiss algorithm

This was done ages ago. It has been working trouble-free for over 2 years.
Closing. John Abbott

11:35 CoCoALib Slug #691 (Closed): Matrix determinant over ZZ

I think this was resolved some time ago when I arranged for the code to recognise the case that the entries are all i... John Abbott

30 Apr 2019

17:18 CoCoALib Design #925: MachineInt or long for args which are indices (yet again)

Postponing because there are too many other more pressing issues. Anyway the current code works adequately, so it is... John Abbott

11:51 CoCoALib Feature #813: Implement "elim" in CoCoALib

It would be nice to complete this before the next release! To this end, I have increased the priority... John Abbott

10:54 CoCoALib Feature #1277: Gaussian row reduction

NTL's doc shows just one fn *@gauss@* which accepts 2 args: matrix @M@ and an optional integer @w@ (default is number... John Abbott

10:44 CoCoALib Feature #1277: Gaussian row reduction

The request seems reasonable to me.
Not yet sure what the best design might be, but I suggest the following as a s... John Abbott

10:40 CoCoALib Feature #1277 (Closed): Gaussian row reduction

Julian Danner (Passau) would like CoCoA to offer matrix row reduction via gaussian elimination.
Discuss, design, i... John Abbott

10:35 CoCoA-5 Bug #1273: NewPolyRing and SymbolRange together make a crash

I must get my CVS access sorted out, so I can check in.
John Abbott

29 Apr 2019

21:05 CoCoALib Support #1276: Release 0.99650

List of principal changes made: *19th november 2019*
* NO LONGER C++03 compatible! We are moving towards C++14 (#89... John Abbott

21:03 CoCoALib Support #1276 (Closed): Release 0.99650

Description
Everything related to making a CoCoALib release:
* Redmine Roadmap: close or postpone issue
* ... John Abbott

18:38 CoCoALib Support #1039 (Resolved): Rename iroot?

I have changed the names into *@FloorRoot@* and *@IsExactFloorRoot@*.
Added *@iroot@* to @obsolescent.H/C@.
Test an... John Abbott

13:25 CoCoALib Support #1039: Rename iroot?

Even though GMP allows negative inputs to its @mpz_root@ function, I like the idea of limiting the number whose root ... John Abbott

18:21 CoCoA-5 Bug #1273: NewPolyRing and SymbolRange together make a crash

Another problem was in @evalArgAsListOfSymbols@ which did a dynamic pointer cast and used the result without checking... John Abbott

14:21 CoCoA-5 Bug #1273 (Resolved): NewPolyRing and SymbolRange together make a crash

One problem appears to be on line 46 of @cocolib.cpkg5@: replace *@[i]@* with just *@i@*.
John Abbott

14:18 CoCoA-5 Bug #1273: NewPolyRing and SymbolRange together make a crash

The *@SymbolRange@* impl looks very suspect. It does not properly check its arg types.
Fn is defd in @coclib.cpkg... John Abbott

14:14 CoCoA-5 Bug #1273 (Closed): NewPolyRing and SymbolRange together make a crash

The problem is with double indices. Here is a small failing example:... John Abbott

18:00 CoCoA-5 Slug #1228: SLUG: filling an array

I think I have found a situation where my simple idea in comment 6 causes trouble...... John Abbott

17:53 CoCoA-5 Slug #1275 (New): incr and decr are slow

The CoCoA-5 functions @incr@ and @decr@ are disappointingly slow.... John Abbott

15:26 CoCoA-5 Bug #1274 (Resolved): SortBy and SortedBy sometimes give wrong result

The bug was at the end of the first loop in *@QuickSortBy1@* where the case @Up = Down@ was not handled.
Added 1 l... John Abbott

14:56 CoCoA-5 Bug #1274 (In Progress): SortBy and SortedBy sometimes give wrong result

Example found by calling @SortedBy@ on random permutations of 1..17.
Seems to work find for lists with only 16 or fe... John Abbott

14:53 CoCoA-5 Bug #1274 (Closed): SortBy and SortedBy sometimes give wrong result

In CoCoA5 the *@SortBy@* and *@SortedBy@* functions sometimes give wrong answers!
Here is an example:... John Abbott

13:57 CoCoALib Support #1263: Tidy CoCoALib test directory

I have noticed that there some tests which run quickly (_e.g._ less than 0.01s on my computer), but the compilation t... John Abbott