Save boolean polynomial ring to file and read it again [closed]

asked 2015-11-03 21:14:56 +0100

Pro
27 ●3 ●3 ●7

updated 2015-11-03 21:39:05 +0100

tmonteil
27413 ●31 ●204 ●517 http://wiki.sagemath.o...

I have BooleanPolynomialRing of 256 variables and I need many thick polynomials. Generate them is very time consuming so I want to save them to file and when needed read again. Is there some good way? Till now I have found out something like this (simplified)

variables=[]
for i in range(1,257):
    variables.append('x'+str(i))
R = BooleanPolynomialRing(names=variables)
R.inject_variables()
fw = open('/home/pro/Desktop/polynomials.txt', 'w')
polynomial = R.random_element(degree=2,terms=+infinity)
fw.write(str(polynomial) + "\n")
fr = open('/home/pro/Desktop/polynomials.txt', 'r')
polynomial = fr.readline()

How can I convert string back to polynomial?

Thanks f.close()

edit retag flag offensive reopen merge delete

Closed for the following reason the question is answered, right answer was accepted by Pro
close date 2015-11-04 22:18:13.453496

add a comment

1

answered 2015-11-03 21:52:43 +0100

tmonteil
27413 ●31 ●204 ●517 http://wiki.sagemath.o...

updated 2015-11-24 09:06:17 +0100

slelievre
17684 ●22 ●160 ●349 http://carva.org/samue...

Instead of using strings, you can directly save the Sage object:

sage: polynomial.save('/home/pro/Desktop/polynomials.sobj')

Then you can load it as follows:

sage: P = load('/home/pro/Desktop/polynomials.sobj')

EDIT

You can save several polynomials in the same file by saving a list of polynomials (but since lists have no save method, you have to use the save function). For example, if P1,P2,P3 are polynomials, you can do:

sage: L = [P1, P2, P3]
sage: save(L, '/home/pro/Desktop/polynomials.sobj')

and then recover it as before:

sage: L = load('/home/pro/Desktop/polynomials.sobj')

and you can then get your polynomials back:

sage: P1, P2, P3 = L

edit flag offensive delete link

Comments

So I need one file for every polynomial right? Is there a way to save multiple polynomials to one file?

Pro ( 2015-11-03 22:24:37 +0100 )edit

I updated my answer to ansver your question.

tmonteil ( 2015-11-03 23:43:09 +0100 )edit

It works perfectly. Thank you very much.

Pro ( 2015-11-04 22:18:56 +0100 )edit

add a comment

0

answered 2015-11-03 21:44:44 +0100

fidbc

2423 ●4 ●26 ●61

updated 2015-11-03 21:53:23 +0100

This may not be the best way to recover a polynomial from its string representation but it appears to work.

Say p = R.random_element(degree=2,terms=+infinity), then s = str(p) gives you its representation as a string. To recover p you can try q = R( eval(s)). Then p==q should evaluate to True.

Now, if you are reading a file fr with a polynomial per line, you can try the following to recover the polynomials.

vars = ['x'+str(i) for i in range(10)]
R= BooleanPolynomialRing(names=vars)
R.inject_variables()
polys = [ R(eval(l[:-1])) for l in fr]

Update: Added iteration through file.

edit flag offensive delete link

Comments

For some other polynomial rings it is probably a better approach to save the coefficients and then reconstruct from the list of coefficients.

fidbc ( 2015-11-03 21:46:02 +0100 )edit

add a comment

Save boolean polynomial ring to file and read it again [closed]

Closed for the following reason the question is answered, right answer was accepted by Pro
close date 2015-11-04 22:18:13.453496

2 Answers

Comments

Comments

Question Tools

Stats

Related questions

Save boolean polynomial ring to file and read it again [closed] edit

Closed for the following reason the question is answered, right answer was accepted by Pro close date 2015-11-04 22:18:13.453496

2 Answers

Comments

Comments

Question Tools

Stats

Related questions

Save boolean polynomial ring to file and read it again [closed]

Closed for the following reason the question is answered, right answer was accepted by Pro
close date 2015-11-04 22:18:13.453496