Abstract Linear Code No Metric Class

[emes4]

With the changes in the coding component, the classes AbstractLinearCode and AbstractLinearRankMetricCode share a lot of the same code. To avoid this and also make creating new linear codes with different metrics easier, we propose to create a new class, AbstractLinearCodeNoMetric, which will stand between AbstractCode and AbstractLinearCode/AbstractLinearRankMetricCode. This class will contain all the methods relevant for linear codes, which do not depend on a metric. In practice this is mostly methods related to generator matrix.

CC: @dimpase @johanrosenkilde @xcaruso @Adurand8

Component: coding theory

Keywords: gsoc19

Author: Marketa Slukova, Amaury Durand

Branch/Commit: 158d73f

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/28350

[emes4]

Branch: u/emes4/28073

[emes4]

Changed branch from u/emes4/28073 to u/emes4/28350

[emes4]

Changed branch from u/emes4/28350 to none

[emes4]

Commit: 45cf76e

[emes4]

Branch: u/gh-emes4/coding/no_metric

[emes4]

Last 10 new commits:

40df01e	Finished up documentation.
01135cb	Merge branch 'develop' of git://trac.sagemath.org/sage into t/28073/abstract_code
ef7b797	Merge branch 'develop' of git://trac.sagemath.org/sage into t/28073/abstract_code
9608a23	Documentation and example fixes.
5230b19	Merge #27634
318b444	Module inheritance. Ambient_space and `__call__` changes.
3996761	Merge commit '8b01cc5df9e1508250976b08b4d2212aecb02927' of git://trac.sagemath.org/sage into t/28073/abstract_code
a4582a3	Merge branch 'develop' of git://trac.sagemath.org/sage into t/28073/abstract_code
4dbc878	documentation fix
45cf76e	Class linear_code_no_metric. Moved stuff from linear_code.

[emes4]

comment:5

I created the class AbstractLinearCodeNoMetric and moved stuff from AbstractLinearCode there, including the category theory set up. I don't understand what the facade does, but when I remove it, the test suite test in LinearCode is unhappy.

The only thing I couldn't get to work was the requirement that the dimension of the code is at most the length. The problem is that the dimension requires a generator matrix (unless it's given) and that causes some issues. I kept the check line commented out in __init__ of AbstractLinearCodeNoMetric.

Unlike AbstractCode, in AbstractLinearCodeNoMetric, it is required that subclasses have default encoders/decoders. This should make sense since we require a generic constructor class.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

01d9a3d

Merge branch 'develop' of git://trac.sagemath.org/sage into t/28350/abstract_linear_code_no_metric_class

[sagetrac-git]

Changed commit from 45cf76e to 01d9a3d

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

226ffbf

Added no metric to coding documentation index. Moved zero method from AbstractLinearCode. Changed base_field check.

[sagetrac-git]

Changed commit from 01d9a3d to 226ffbf

[emes4]

comment:10

Updated Sage.

Added linear_code_no_metric.py to the index of coding module documentation.

Moved zero method from AbstractLinearCode.

Changed base_field check message.

[dimpase]

comment:11

with python3:
(i.e. doing ./configure --with-python=3 && make)

sage -t src/sage/coding/decoder.py
**********************************************************************
File "src/sage/coding/decoder.py", line 197, in sage.coding.decoder.Decoder.__hash__
Failed example:
    hash(D) #random
Exception raised:
    Traceback (most recent call last):
      File "/mnt/opt/Sage/sage-dev/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 681, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/mnt/opt/Sage/sage-dev/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 1123, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.coding.decoder.Decoder.__hash__[3]>", line 1, in <module>
        hash(D) #random
      File "/mnt/opt/Sage/sage-dev/local/lib/python3.7/site-packages/sage/coding/linear_code.py", line 2632, in __hash__
        return hash((self.code(), self.maximum_error_weight()))
    TypeError: unhashable type: 'LinearCode_with_category'
**********************************************************************

this causes more errors

sage -t src/sage/coding/decoder.py  # 1 doctest failed
sage -t src/sage/coding/linear_code_no_metric.py  # 2 doctests failed
sage -t src/sage/coding/linear_code.py  # 1 doctest failed

[dimpase]

comment:14

Any chance this could be brought forward - it holds up few more tickets...

[johanrosenkilde]

comment:15

I unfortunately don't have any time to move on this currently :-(

[emes4]

comment:16

I will have a look at it this week!

[embray]

comment:17

Ticket retargeted after milestone closed

[Adurand8]

Changed branch from u/gh-emes4/coding/no_metric to u/gh-Adurand8/coding/no_metric

[xcaruso]

Changed commit from 226ffbf to dbaaaa1

[xcaruso]

comment:19

Hello,

I'm not really satisfied with the names of the classes.
Instead, I would propose the following hierarchy:

AbstractCode
  AbstractLinearCode
    AbstractLinearMetricCode
      AbstractLinearHammingMetricCode  # if relevant
      AbstractLinearRankMetricCode

Also, through it is not directly related to this ticket, I don't understand the purpose of the class LinearCode...

---

New commits:

d49390e	merged version 9.1.beta1
80ff011	Add function hash
dbaaaa1	Merge branch 'develop' into t/28350/coding/no_metric

[sagetrac-git]

Changed commit from dbaaaa1 to db3b18a

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

db3b18a

Error commit on linear_code_no_metric in precedent commit

[dimpase]

comment:21

Replying to @xcaruso:

I'm not really satisfied with the names of the classes.

I'd propose that we complete this ticket and #28209 (which depends on this ticket) with as few chnages as posssible,
and then go on with renaming/redesigning.

[dimpase]

comment:22

tests pass now. Is it ready for review?

[dimpase]

Changed author from Marketa Slukova to Marketa Slukova, Durand Amaury

[dimpase]

Changed author from Marketa Slukova, Durand Amaury to Marketa Slukova, Amaury Durand

[dimpase]

comment:24

Ping?

[johanrosenkilde]

comment:25

Dima, is there a specific reason you refrain from reviewing yourself? I'm completely swamped right now, so there's no chance I'll do it any time soon, but I remember being fairly happy about the design during GSoC.

@xcaruso: Concerning your proposed naming, I guess your names are better from a completely general point of view. The current naming is for "historic reasons" centering on classical "linear codes over Hamming metric" being what everyone would expect. So in some sense the names follow the principal of least surprise by specifically pointing out in the name when it differs from the "expected". But I think I could easily be talked into going with your hierarchy.

The purpose of LinearCode btw is to act as a thin wrapper around AbstractLinearCode for constructing "unstructured" codes directly from a generator matrix. That's an essential class for users. The distinction from AbstractLinearCode was created as part of the encoder-framework (long story), but is a typical way to construct a class hierarchy in more strongly typed languages: if I could do so in Python, I would specify on a type level that AbstractLinearCode is not supposed to be instantiated directly.

[dimpase]

comment:26

I was not reviewing as the ticket is set to needs work. So I've set it to needs review and to positive review now.

[dimpase]

Reviewer: Dima Pasechnik

[vbraun]

comment:27

Merge conflit

[dimpase]

comment:28

rebased

---

New commits:

244f4af	Class linear_code_no_metric. Moved stuff from linear_code.
c716526	Added no metric to coding documentation index. Moved zero method from AbstractLinearCode. Changed base_field check.
0b5baa0	Add function hash
158d73f	Error commit on linear_code_no_metric in precedent commit

[dimpase]

Changed commit from db3b18a to 158d73f

[dimpase]

Changed dependencies from #28073 to none

[dimpase]

Changed branch from u/gh-Adurand8/coding/no_metric to u/dimpase/coding/no_metric

[vbraun]

Changed branch from u/dimpase/coding/no_metric to 158d73f