Trouble with deepcopy of vectorspaces where the inner product matrix is specified

[jonhanke]

There are some serious problems using deepcopy on vectorspaces where the inner_product_matrix is specified. This fails over GF(p) for large primes, and over RR.

Please see also Ticket #10577 for a related problem over GF(2).

sage: V = VectorSpace(GF(46337), 2, inner_product_matrix=DiagonalMatrix(ZZ, [1,1]))
sage: deepcopy(V)
Ambient quadratic space of dimension 2 over Finite Field of size 46337
Inner product matrix:
[1 0]
[0 1]
sage: 
sage: V = VectorSpace(GF(46349), 2, inner_product_matrix=DiagonalMatrix(ZZ, [1,1]))
sage: deepcopy(V)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/Users/jonhanke/Documents/SAGE/sage-4.6/<ipython console> in <module>()

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in deepcopy(x, memo, _nil)
    187                             raise Error(
    188                                 "un(deep)copyable object of type %s" % cls)
--> 189                 y = _reconstruct(x, rv, 1, memo)
    190 
    191     memo[d] = y

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in _reconstruct(x, info, deep, memo)
    320         dictiter = None
    321     if deep:
--> 322         args = deepcopy(args, memo)
    323     y = callable(*args)
    324     memo[id(x)] = y

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in deepcopy(x, memo, _nil)
    160     copier = _deepcopy_dispatch.get(cls)
    161     if copier:
--> 162         y = copier(x, memo)
    163     else:
    164         try:

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in _deepcopy_tuple(x, memo)
    233     y = []
    234     for a in x:
--> 235         y.append(deepcopy(a, memo))
    236     d = id(x)
    237     try:

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in deepcopy(x, memo, _nil)
    160     copier = _deepcopy_dispatch.get(cls)
    161     if copier:
--> 162         y = copier(x, memo)
    163     else:
    164         try:

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in _deepcopy_tuple(x, memo)
    233     y = []
    234     for a in x:
--> 235         y.append(deepcopy(a, memo))
    236     d = id(x)
    237     try:

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python/copy.pyc in deepcopy(x, memo, _nil)
    171             copier = getattr(x, "__deepcopy__", None)
    172             if copier:
--> 173                 y = copier(memo)
    174             else:
    175                 reductor = dispatch_table.get(cls)

TypeError: __deepcopy__() takes no arguments (1 given)

CC: @williamstein @jonhanke

Component: linear algebra

Keywords: copy, vectorspace

Author: Frédéric Chapoton

Branch/Commit: bf855a3

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/10606

[fchapoton]

comment:5

Works in 8.2.b7

[simonbrandhorst]

comment:6

Shouldn't we add a doctest to show the bug is fixed?

[tscrim]

comment:7

Replying to @simonbrandhorst:

Shouldn't we add a doctest to show the bug is fixed?

Feel free to add one.

[fchapoton]

Changed author from Jonathan Hanke to Frédéric Chapoton

[fchapoton]

Branch: u/chapoton/10606

[fchapoton]

Commit: eb0d0d5

[fchapoton]

comment:8

doctest added, please review

---

New commits:

eb0d0d5

trac 10606 adding a doctest

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:9

LGTM.

[fchapoton]

comment:11

there is a typo Z Z

[sagetrac-git]

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

6ba9925

fix a typo

[sagetrac-git]

Changed commit from eb0d0d5 to 6ba9925

[fchapoton]

comment:13

corrected and tested. I am setting back to positive

[fchapoton]

comment:14

pyflakes plugin is not happy

[sagetrac-git]

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

bf855a3

fixing pyflakes

[sagetrac-git]

Changed commit from 6ba9925 to bf855a3

[fchapoton]

comment:16

done, setting back to positive

[vbraun]

Changed branch from u/chapoton/10606 to bf855a3