Secondary Fans using gfan

[simon]

Hello,

I'm trying to compute the secondary fan of a vector configuration as described e.g. in

http://www.polymake.org/doku.php/news/release_2_10

I have both polymake 2.11 and gfan 0.5 installed.
However, my installation of polymake does not know about a function "secondary_fan".

Maybe I have to tell polymake first about gfan?

Thanks in advance!

[joswig]

You may have to do

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reconfigure "gfan.rules";

in application fan.

[simon]

ah sure! Thanks!

[esche]

Hi!

I have the same problem here. I use polymake 2.12 and gfan 0.5 in Mac OS X 10.6. The subroutine secondary_fan is undefined and I get the error message

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polytope > reconfigure "gfan.rules"; polymake: ERROR: there are no configuration actions associated with rulefile gfan.rules

Do you have some advice ? Thanks in advance.

esche

[blorenz]

The gfan rules are within application fan and therefore you need to switch to that application before reconfiguring or using the secondary_fan function:

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application "fan"; reconfigure "gfan.rules"; $f = secondary_fan($m);

Ben

[esche]

Thanks a lot for the quick reply. Now, I have the next problem:

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$ptmat = new Matrix<Integer>([[1,0,0,0,0],[1,2,-1,-1,-1],[1,-1,2,-1,-1],[1,-1,-1,-1,-1],[1,0,0,1,0],[1,0,0,0,1]]); $P = new Polytope<Rational>(POINTS=>$ptmat); $Sigma = fan::secondary_fan($P->VERTICES); polymake: transforming /private/var/folders/NQ/NQnbaTxVHAecd8YXcj+MPE+++TI/-Tmp-/poly2028Taaaa0001.poly with upgrade-2.9.10.xslt polymake: transforming /private/var/folders/NQ/NQnbaTxVHAecd8YXcj+MPE+++TI/-Tmp-/poly2028Taaaa0001.poly with upgrade-2.10.xslt polymake: transforming /private/var/folders/NQ/NQnbaTxVHAecd8YXcj+MPE+++TI/-Tmp-/poly2028Taaaa0001.poly with upgrade-2.11.xslt polymake: transforming /private/var/folders/NQ/NQnbaTxVHAecd8YXcj+MPE+++TI/-Tmp-/poly2028Taaaa0001.poly with upgrade-2.12.xslt polymake: WARNING: encountered unknown property 'AMBIENT_DIM' in object SymmetricFan<Rational> Please be aware that all unknown properties are automatically removed from the data files. If you want to supply additional information with the objects, please use attachments or declare new properties in extension rules. polymake: WARNING: Creating backup file /private/var/folders/NQ/NQnbaTxVHAecd8YXcj+MPE+++TI/-Tmp-/poly2028Taaaa0001.poly.bak polymake: WARNING: encountered unknown property 'DIM' in object SymmetricFan<Rational>

Can you give me a hint what I am supposed to do here ?

esche

[joswig]

Can you give me a hint what I am supposed to do here ?

Nothing.

polymake transformed your files into a new format. On the way it trashed the properties DIM and AMBIENT_DIM which became user functions. That's why you got a warning (but no error). No information lost in your data.

[esche]

I see. Then how do I get the 1-dimensional cones ? Or the maximal cones ? I seem to get an empty result which I know not to be true.

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print $Sigma->MAXIMAL_CONES; {}

esche

[joswig]

OK, there is a bug in apps/fan/rules/gfan.rules.

Please replace the line 41 by

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gfan_print_matrix($tempfile,eliminate_denominators_entire_affine($M->minor(All,[1..$M->cols()-1])));

Sorry for the inconvenience.

[esche]

Thanks. Now I'm getting the following error message

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fan > $Sigma = fan::secondary_fan($P->VERTICES); polymake: used package gfan Gfan is a software package for computing Groebner fans and tropical varieties. Copyright by Anders Jensen http://www.math.tu-berlin.de/~jensen/software/gfan/gfan.html polymake: Creating tree /Users/esche/.polymake-macbundle/wrappers/core for automatically generated private C++/perl wrappers polymake: ERROR: Undefined subroutine &Polymake::fan::eliminate_denominators_entire_affine called at /Applications/polymake.app/Contents/MacOS/../Resources//polymake/share/polymake/apps/fan/rules/gfan.rules line 41.

esche