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import sage packages in python

asked 2012-09-06 13:29:57 +0200

MaelstromYamato gravatar image

updated 2012-09-06 14:02:41 +0200

kcrisman gravatar image

An easy way to use sage in python files is demonstrated in the Sage Tutorial.

#!/usr/bin/env sage -python

import sys
from sage.all import *

if len(sys.argv) != 2:
    print "Usage: %s <n>"%sys.argv[0]
    print "Outputs the prime factorization of n."

print factor(sage_eval(sys.argv[1]))

Well, what if I don't want to import all of sage as shown above using:

from sage.all import *

Instead of this command above, I just want to import the following:

  1. Matrix -> type 'sage.matrix.matrix_integer_dense.Matrix_integer_dense'
  2. vector -> type 'sage.modules.vector_integer_dense.Vector_integer_dense'
  3. ZZ -> type 'sage.rings.integer_ring.IntegerRing_class'
  4. MixedIntegerLinearProgram -> type 'sage.numerical.mip.MixedIntegerLinearProgram'

So I should be able to write something like this in python

from sage.library.package.for.Matrix import *
from sage.library.package.for.vector import *
from sage.library.package.for.ZZ import *
from sage.library.package.for.MixedIntegerLinearProgram import *

I just don't know what they are. Any help is appreciated.


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I'd be really careful with this. The cascade of imports is very convoluted, and there isn't any guarantee that importing something like `ZZ` won't import most of the rest of Sage. It may not be worth the effort.

kcrisman gravatar imagekcrisman ( 2012-09-06 14:03:39 +0200 )edit

2 Answers

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answered 2012-09-06 14:08:28 +0200

updated 2012-09-06 18:14:35 +0200

  1. Matrix -> type 'sage.matrix.matrix_integer_dense.Matrix_integer_dense'

    from sage.matrix.all import Matrix


    from sage.matrix.constructor import Matrix

  2. vector -> type 'sage.modules.vector_integer_dense.Vector_integer_dense'

    from sage.modules.free_module_element import vector

  3. ZZ -> type 'sage.rings.integer_ring.IntegerRing_class'

    from sage.rings.integer_ring import ZZ

  4. MixedIntegerLinearProgram -> type 'sage.numerical.mip.MixedIntegerLinearProgram'

    from sage.numerical.mip import MixedIntegerLinearProgram

Once you know roughly where the class is defined, for example Matrix is defined somewhere in SAGE_ROOT/devel/sage/sage/matrix/, take a look at the file in that directory. In this case you'll find a line

from constructor import matrix, Matrix, column_matrix, random_matrix, diagonal_matrix, identity_matrix, block_matrix, block_diagonal_matrix, jordan_block, zero_matrix, ones_matrix, elementary_matrix, companion_matrix

So that tells you that you can import Matrix from sage.matrix.all or from sage.matrix.constructor. Your other examples can be dealt with similarly.

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Thanks. This does help!

MaelstromYamato gravatar imageMaelstromYamato ( 2012-09-06 14:47:58 +0200 )edit

But this suggestion results in ImportError: cannot import name ZZ.

ml9nn gravatar imageml9nn ( 2018-02-03 18:09:44 +0200 )edit

Sage has changed in the past 5 1/2 years, so whatever suggestion may have worked then may not be valid any more. If you want to ask a new question, please do so.

John Palmieri gravatar imageJohn Palmieri ( 2018-02-19 23:27:01 +0200 )edit

answered 2012-09-06 15:03:33 +0200

Jason Grout gravatar image

updated 2012-09-06 15:05:37 +0200

It seems you are trying to avoid cluttering the namespace? Then do this:

import sage.all
from sage.all import Matrix,vector,ZZ, MixedIntegerLinearProgram

kcrisman was right---lots of Sage depends on lots of other things in Sage, and importing just a piece (i.e., without doing import sage.all) is definitely not supported and may often break or not provide any benefit.

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Ah, the namespace. See, this doesn't occur to me :)

kcrisman gravatar imagekcrisman ( 2012-09-06 15:58:02 +0200 )edit

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Asked: 2012-09-06 13:29:57 +0200

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Last updated: Sep 06 '12