On Thursday, June 30, 2016 at 6:33:14 PM UTC+1, [email protected] wrote:
>
> Thank you sir! I am new to these string manipulations, it worked like a
> charm!
> Maybe there is a shorter way to do this, but as I've learned from you, I
> did the following:
>
> macaulay2('loadPackage "Graphs"')
> G = Graph({1:[2], 2:[1,3], 3:[2,4], 4:[3]})
> E=G.edges()
> macaulay2('EG={}')
> for i in range(len(E)):
> macaulay2('e={}')
> macaulay2('e=append(e,'+str(E[i][0])+')')
> macaulay2('e=append(e,'+str(E[i][1])+')')
> macaulay2('EG=append(EG,e)')
> macaulay2('H = graph(EG)')
>
> this is very sub-optimal; you should not call M2 in the loop, unless
absolutely necessary.
Also, Python has quite powerful string manipulation routines and functional
programming operations.
Here is the code that does the same as above, and much faster:
macaulay2('loadPackage "Graphs"')
G = Graph({1:[2], 2:[1,3], 3:[2,4], 4:[3]})
macaulay2('H = graph({'+','.join(map(lambda (x,y,_):
'{'+str(x)+','+str(y)+'}', G.edges()))+'})')
Now it seems easier for ideals. Thank you again! :)
>
>
> 30 Haziran 2016 Perşembe 13:11:25 UTC+3 tarihinde Dima Pasechnik yazdı:
>>
>> Basically, you need to build, in Sage, a string to pass to M2. E.g.:
>>
>> sage: a=1; b=31; macaulay2('G =
>> graph({{'+str(a)+',2},{2,'+str(b)+'},{'+str(b)+',4}})')
>> Graph{1 => {2} }
>> 2 => {1, 31}
>> 4 => {31}
>> 31 => {2, 4}
>>
>> Ideally, you'd develop methods for Sage types to convert them to M2 types.
>> So that macaulay2(G) would create a handle to a M2 object which is an M2
>> graph.
>> Currently there are such functions for rings, polynomials, and ideals:
>>
>> sage: R2 = macaulay2.ring('QQ', '[x, y]'); R2 # optional -
>> macaulay2QQ[x..y, Degrees => {2:1}, Heft => {1}, MonomialOrder =>
>> {MonomialSize => 16}, DegreeRank => 1]
>> {Lex => 2 }
>> {Position => Up }sage: I = macaulay2.ideal( ('y^2 -
>> x^3', 'x - y') ); I # optional - macaulay2
>>
>>
>>
>>
>>
>> On Thursday, June 30, 2016 at 9:36:19 AM UTC+1, [email protected]
>> wrote:
>>>
>>> Hi,
>>>
>>> I do some calculations about graphs and ideals via M2 interface of Sage
>>> or just using M2, but for that, I have to use M2 input as below:
>>>
>>> sage: macaulay2('loadPackage "Graphs"')
>>> sage: macaulay2('G = graph({{1,2},{2,3},{3,4}})')
>>>
>>> as explained in the link:
>>>
>>> http://math.uiuc.edu/Macaulay2/doc/Macaulay2-1.8.2/share/doc/Macaulay2/Graphs/html/_graph.html
>>> Is there a way to convert a graph or an ideal written in Sage code into
>>> Maculay2 ones so that it can be employed in M2 interface. For instance,
>>>
>>> sage: d={1:[2], 2:[1,3], 3:[2,4], 4:[3]}
>>>
>>>
>>> sage: G = Graph(d)
>>>
>>> sage: macaulay2('H=graph(G)') (or H=macaulay2('graph(G)'))
>>>
>>>
>>> Of course M2 won't accept my silly code in the 3rd line, but I've tried
>>> various ways like injecting a square free-quadratic-monomial ideal or edge
>>> list of a graph into M2 and I always fail.
>>> I also have the same problem for ideals.
>>>
>>> It's a long-standing problem of mine and it costs me writing heavy codes in
>>> Sage for multiple calculations. Calculating via M2 with Sage inputs will
>>> save lots of my time.
>>>
>>> Can anyone help?
>>>
>>> Thanks in advance! :)
>>>
>>>
>>> Best Regards
>>>
>>> Mehmet
>>>
>>>
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