Re: Polyhedron construction fails on specific list of vertices

[Volker Braun]

I can confirm this. The problem is that cdd errors out with "*Error: Numerical inconsistency is found.  Use the GMP exact arithmetic.". Gee, thanks ;)

On Tuesday, April 23, 2013 9:09:08 AM UTC+1, Felix Wellen wrote:

while trying to render the intersection of a 4-cube and a 3-cube (I guess that really doesn't matter), I stopped on trouble with the following:

[Volker Braun]

This is now http://trac.sagemath.org/14479 (needs review)

[Nathann Cohen]

This is now http://trac.sagemath.org/14479 (needs review)

I love your style ! :-D

It says "Welcome in the world of Sage, where no known bug makes it past the day" :-D

Nathann 

[Felix Wellen]

With "backend='ppl', base_ring=QQ" it works!

Thanks again ;)

[abhishek]

Hello All, 

I am a new user of SAGE. I need to know how to control flow of how to control execution according to data type. As in a given loop I want to execute loop further only if variable is of a integer type. 

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[Volker Braun]

Its bad practice in Python to depend explicitly on the specific type. You should implement your algorithm such that it does not matter if the type is exactly a Sage integer or just something that behaves like an integer:

try:

    ... do something ...

except ValueError:

    ... not an integer? ...

The second-best solution is to see if it is something that can be converted into ZZ:

sage: 5 in ZZ

True

sage: 5/2 in ZZ

False

The worst solution is to look directly at the type:

sage: isinstance(5, sage.rings.integer.Integer)

True