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save definitions

asked 2012-03-16 07:53:13 +0200

emiliocba gravatar image

Hello,

I want to use save a definition in the interactive shell. For example, I define

sage: def F(m):
....:     return 2*m
....:

I put

sage: save(F,'function')

but it doesn't work. How can I do to save this definition and then load to work with it.

Thanks.-.

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niles gravatar imageniles ( 2012-03-16 13:48:48 +0200 )edit

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answered 2012-03-16 10:20:35 +0200

Simon King gravatar image

Saving functions is a general problem with Python (and Python is Sage's language). But Sage provides a partial solution in the modules sage.misc.fpickle. That module contains a function pickle_function, that translates a given function into a string (and then you can save the string). And it also contains a function unpickle_function, that translates that string into a function.

Example:

sage: from sage.misc.fpickle import pickle_function, unpickle_function
sage: def my_func(x): return x^2
....: 
sage: tmp = tmp_filename()
sage: save(pickle_function(my_func), tmp)
sage: recovered_function = unpickle_function(load(tmp))
sage: recovered_function(5)
25

pickle_function does have limitations (as explained in the docs), but perhaps it is enough for your application?

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Asked: 2012-03-16 07:53:13 +0200

Seen: 381 times

Last updated: Mar 16 '12