Optimize linear codes: __eq__, dual_code and commented debug lines

[sagetrac-dlucas]

Some code in LinearCode.py is quite old and/or slow, and could be optimized.
This tickets proposes a faster implementation for __eq__ and dual_code methods.
It also removes a lot of commented debug lines.

Component: coding theory

Author: David Lucas

Branch/Commit: b869837

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/19492

[sagetrac-dlucas]

Branch: u/dlucas/clean_linear_code

[sagetrac-dlucas]

Commit: d64c360

[sagetrac-dlucas]

comment:2

Let C be a linear code with H a parity check matrix of C. The generator matrix of C's dual is H. I made changes in AbstractLinearCode's dual_code method to use that property instead of the old implementation and got something faster.

I also rewrote AbstractLinearCode's __eq__ which is now less heavy and a bit faster.

Finally, I removed a lot of old debug prints that were still present in this file as commented lines.

This is now ready for review.

---

New commits:

eba939b	Changes in dual_code method
d64c360	Changes in `__eq__` method, removed commented debug lines

[sagetrac-dlucas]

Author: David Lucas

[videlec]

comment:4

The following would be cleaner on two lines.

+        Ks, rbas = self.parity_check_matrix().right_kernel(), right.gens()

Otherwise it looks good.

[sagetrac-git]

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

f3a7f07

Integrated reviewer's comment

[sagetrac-git]

Changed commit from d64c360 to f3a7f07

[sagetrac-dlucas]

comment:6

Thanks for your input.

I changed the code to what you suggested. I also fixed a silly copy-paste mistake two lines below the one you mentioned.

David

[videlec]

comment:7

While you are at it, the print statements like

print " t = ",t," , v = ",n," , k = ",w," , lambda = ",wts[w]*binomial(w,t)/binomial(n,t)

are really ugly. Could you do something cleaner like

print "t={} v={} k={} lambda={}".format(t, n, w, wts[w]*binomial(w,t)/binomial(n,t))

[jdemeyer]

comment:8

Even better would be

print("t={} v={} k={} lambda={}".format(t, n, w, wts[w]*binomial(w,t)/binomial(n,t)))

since that's compatible with Python 2 and 3.

[sagetrac-git]

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

b869837

Changed some print statements to something cleaner

[sagetrac-git]

Changed commit from f3a7f07 to b869837

[sagetrac-dlucas]

comment:10

It's done.
I picked Jeroen's suggestion for the new statements.

[videlec]

Reviewer: Vincent Delecroix

[vbraun]

Changed branch from u/dlucas/clean_linear_code to b869837