20191109 14:34:12 0600  commented question  How to create a subgroup with MAGMA inside SAGE of a group created with MAGMA inside SAGE? Thank you very much for your comment! :) 
20191109 14:33:58 0600  commented answer  How to create a subgroup with MAGMA inside SAGE of a group created with MAGMA inside SAGE? Thank you very much for your answer! :) 
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20191108 12:14:46 0600  asked a question  How to create a subgroup with MAGMA inside SAGE of a group created with MAGMA inside SAGE? Dear SAGE team, I would like to let MAGMA inside SAGE create a subgroup of a group (which was also created with MAGMA inside SAGE), but an error message was returned. Unfortunately, I don't know ho to resolve this. I would be thankful for any help. Here's the code (only an example):
The error message is as follows: TypeError Traceback (most recent call last) <ipythoninput13da9ee2cf66f9> in <module>() > 1 GG_MAGMA=magma.new('sub<ggg[(1,2)]>')< p=""> /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/interface.pyc in new(self, code) 351 352 def new(self, code): > 353 return self(code) 354 355 ################################################################### /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/magma.pyc in __call__(self, x, gens) 792 pass 793 > 794 A = Expect.__call__(self, x) 795 if has_cache: 796 x._magma_cache[self] = A /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/interface.pyc in __call__(self, x, name) 286 287 if isinstance(x, string_types): > 288 return cls(self, x, name=name) 289 try: 290 return self._coerce_from_special_method(x) /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/expect.pyc in __init__(self, parent, value, is_name, name) 1441 except (RuntimeError, ValueError) as x: 1442 self._session_number = 1 > 1443 raise_(TypeError, TypeError(*x.args), sys.exc_info()[2]) 1444 except BaseException: 1445 self._session_number = 1 /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/expect.pyc in __init__(self, parent, value, is_name, name) 1436 else: 1437 try: > 1438 self._name = parent._create(value, name=name) 1439 # Convert ValueError and RuntimeError to TypeError for 1440 # coercion to work properly. /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/interface.pyc in _create(self, value, name) 482 def _create(self, value, name=None): 483 name = self._next_var_name() if name is None else name > 484 self.set(name, value) 485 return name 486 /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/magma.pyc in set(self, var, value) 627 13/5 628 """ > 629 out = self.eval("%s:=%s" % (var, value)) 630 if out.lower().find("error") != 1: 631 raise TypeError("Error executing Magma code:\n%s" % out) /var/autofs/nfs/scratch/hannes/sage8.8/local/lib/python2.7/sitepackages/sage/interfaces/magma.pyc in eval(self, x, strip, *kwds) 561 ans = Expect.eval(self, x, *kwds).replace('\\n', '') 562 if 'Runtime error' in ans or 'User error' in ans: > 563 raise RuntimeError("Error evaluating Magma code.\nIN:%s\nOUT:%s" % (x, ans)) 564 return ans 565 TypeError: Error evaluating Magma code. IN:_sage_[3]:=sub<ggg[(1,2)]>; out:<="" p="">

20191108 12:01:16 0600  commented answer  How to connect Magma_free, SAGE and GAP (problem concerning a MAGMA string not readable by GAP)? Thank you very much for your answer! :) To whom it may concern: In the meantime I got to know that the following is also a possible solution (exemplarily done for G=$S_4$): gap.LoadPackage('"ctbllib"') ct=magma_free("G:=Sym(4);ct:=CharacterTable(G);ct;") myfile=file("tbl_MAGMA.txt", 'w') print >> myfile, ct print >> myfile.close() tbl=gap.GAPTableOfMagmaFile('"tbl_MAGMA.txt"', '"MAGMA_TBL"') gap.Display(tbl) G=gap.SymmetricGroup(4) gap.ConnectGroupAndCharacterTable(G,tbl) 
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20190201 10:23:52 0600  asked a question  How to connect Magma_free, SAGE and GAP (problem concerning a MAGMA string not readable by GAP)? Hi, I'd like to ask the following: I'd like to use SAGE in order to compute something with the free magma online calculator and then convert it into a GAP object. Unfortunately, there occurs an error, and I don't know, how to fix this. Any help is very much appreciated. I followed the example on page 91 of http://www.math.rwthaachen.de/~Thoma... Here is what I did: 
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20180120 08:47:45 0600  commented answer  Can SAGE calculate with projective (indecomposable) Amodules (A is a finite dimensional Qalgebra)? Thank you very much for your answer. I was thinking of the kdimension of the algebra. I should have written that in the question. Sorry for my late reply. As a comment, I would like to say that in the meantime I have learned that these things can be done with the aid of the GAPpackage QPA. This also works in SAGE via letting GAP be the intermediator. 
20180120 08:44:19 0600  commented answer  Dotted and dashed lines in directed graphs Thank you for your answer. Maybe the answer to thie following other question of mine is also helpful: https://ask.sagemath.org/question/356... 
20180120 08:42:39 0600  commented question  Compute radical and idempotents of a quotient algebra In the meantime I have learned that these things can be done for admissible quotients of path algebras with the aid of the GAPpackage QPA. This also works in SAGE via letting GAP be the intermediator. So, if we make the additional restriction that our algebra is commutative, it works as follows: If we let $k$ be a finite field, then the command IdempotentsForDecomposition(A); works, but I don't have a computational solution for the case $k=\mathbb{Q}$. I have not yet a solution for the noncommutative case. 
20180120 08:18:22 0600  commented answer  Drawing AuslanderReiten quivers with sage possible? Thank you very much for your answer (and sorry for my very late reply). It works perfectly fine! :) 
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20161118 08:51:08 0600  commented question  Drawing AuslanderReiten quivers with sage possible? Thank you very much for your comment. I edited the question. 
20161118 07:49:43 0600  asked a question  Drawing AuslanderReiten quivers with sage possible? Hi, I'd like to draw an AuslanderReiten quiver with sage. I tried to do this by viewing the AuslanderReiten quiver as a digraph, but, unfortunately, I was not able to find out how to let sage draw both dashed and solid arrows in one digraph. Is this possible? If not, is there another way to let sage draw AuslanderReiten quivers? Any help would be appreciated. Edit: I used the following code: sage: H=DiGraph() sage: H.add_edges([(2,1),(2,4),(10,4),(1,3),(4,3),(4,11),(11,6),(3,6),(3,5),(5,7),(6,7),(6,12)]) sage: H.add_edges([(7,8),(7,9),(12,9)]) After having typed sage: H.show() a few times I got the following output: Now, I'd like to draw dahed arrows indicating the AuslanderReiten translates (e.g. a dashed arrow from 3 to 2). 
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20151203 20:39:18 0600  asked a question  Dotted and dashed lines in directed graphs Hi, I would like to know if it is possible to do (one of) the following with Sage. Reading http://doc.sagemath.org/html/en/refer... I saw that it is possible to draw dashed and dotted lines. Now my questions are 1) Is it possible to produce an output graphic where some edges are dotted and some edges are dashed? 2) Is it possible to force the text in the labels of the vertices, e.g. M2, M4, M1 instead of 0,1,2? Thanks for the help! 
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20151127 06:49:00 0600  commented answer  How to make pygraphviz and sage compatible? Thank you very much for your answer. 
20151125 21:08:31 0600  commented answer  How to draw special trees from a list consisting of tuples with Sage? Thank you very much for your answer. 
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20151125 21:07:58 0600  marked best answer  How to draw special trees from a list consisting of tuples with Sage? I have the following problem: Imagine, we have tuples (1,1), (1,2), ... , (1,n), (2,1), (2,2), (2,n), (3,1), ... , (k,n) in a list To every tuple I would like the PC to draw trees in the following manner: In the first level, there is one tuple T. This was manually chosen from the list In the second level, there are all the tuples In the third level, for each tuple Iterate this, until the process stops (is finished) and you have drawn a tree. The arrows of the tree are just edges and the points are the tuples, that should be numbered by Here is a small example: This gives the following tree for Not only the tree, but also its "longest" branches (i.e. these, that can no more be extended by the procedure above...in the above example, these are Now, my question is:
Thanks for the help! 
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20151125 20:42:50 0600  asked a question  How to make pygraphviz and sage compatible? Hi, I would like sage to help me when I am working with (un)directed graphs and quivers, and so on. After having played around with various possibilities, I would like to convert some stuff into a string and then let sage print something like a .ps  file that contains an image from dot (or something similar to this).
Could you help me understand and solve the following: boehmler@boehmlerX55A:~/Schreibtisch/bb/sage6.9x86_64Linux$ ./sage ┌────────────────────────────────────────────────────────────────────┐ │ SageMath Version 6.9, Release Date: 20151010 │ │ Type "notebook()" for the browserbased notebook interface. │ │ Type "help()" for help. │ └────────────────────────────────────────────────────────────────────┘ sage: import networkx as nx sage: import matplotlib.pyplot as plt sage: import matplotlib.image as mpimg sage: from cStringIO import StringIO sage: g = nx.dodecahedral_graph() sage: d = nx.to_pydot(g) AttributeError Traceback (most recent call last) <ipythoninput60d33c400a5cf> in <module>() > 1 d = nx.to_pydot(g) AttributeError: 'module' object has no attribute 'to_pydot' sage: d = nx.to_agraph(g) ImportError Traceback (most recent call last) <ipythoninput7d9254026fb59> in <module>() > 1 d = nx.to_agraph(g) /home/boehmler/Schreibtisch/bb/sage6.9x86_64Linux/local/lib/python/networkx/drawing/nx_agraph.pyc in to_agraph(N) > 134 '(not available for Python3)') ImportError: ('requires pygraphviz ', 'http://networkx.lanl.gov/pygraphviz ', '(not available for Python3)') sage: Exiting Sage (CPU time 0m3.33s, Wall time 56m28.80s). After typing boehmler@boehmlerX55A:~/Schreibtisch/bb/sage6.9x86_64Linux$ sudo H pip install pygraphviz I get the message Wall Wstrictprototypes fPIC I/usr/include/graphviz I/usr/include/python2.7 c pygraphviz/graphviz_wrap.c o build/temp.linuxx86_642.7/pygraphviz/graphviz_wrap.o pygraphviz/graphviz_wrap.c:130:21: fatal error: Python.h: Datei oder Verzeichnis nicht gefunden # include <python.h> ^ compilation terminated. error: command 'x86_64linuxgnugcc' failed with exit status 1 Command "/usr/bin/python c "import setuptools, tokenize;__file__='/tmp/pipbuild6yZh3l/pygraphviz/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install record /tmp/pipa6o8Fgrecord/installrecord.txt singleversionexternallymanaged compile" failed with error code 1 in /tmp/pipbuild6yZh3l/pygraphviz in the end. I would be grateful for any hints how to solve / fix this. Thanks for the help! 
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