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Why do I get the "unable to find a common ring for all elements" error message?

asked 2013-11-17 13:46:09 -0500

Behzad gravatar image

I was wondering if you can take a look at this cell:

and let me know why I get the error message.


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answered 2013-11-17 14:32:30 -0500

ppurka gravatar image

The variables in the MILP are not symbolic variables, i.e., not from the Symbolic Ring. The vector() command is failing in that step.

<type 'sage.numerical.linear_functions.LinearFunction'>

You can rewrite your constraints like this

p.add_constraint(sum(_a*_x for _a,_x in zip(a1, [x,y])) + r*a1.norm(2) <= b1)
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Basically, you are reimplementing the dot product. That seems like a "bad thing". Obviously linear algebra and linear programming should play well together - can this actually be done?

Saul Schleimer gravatar imageSaul Schleimer ( 2015-09-06 21:23:14 -0500 )edit

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Asked: 2013-11-17 13:46:09 -0500

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Last updated: Nov 17 '13