lcz

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1 years, 143 days

MaplePrimes Activity


These are replies submitted by lcz

@Carl Love  Thanks I learn another good trick from you.

@nm   extremely grateful

@nm  Thanks ! For simplicity,  furthermore I'd like to let (5435 + 3*sqrt(515793))^(1/3)=t, but fail.

subs((5435 + 3*sqrt(515793))^(1/3)=t,s1)

@tomleslie  This is good, but it seems to be less thorough than the above method of vv.

@vv  Thnaks!   expand is  more  stronger than simplify and value. It's weird.

@Carl Love 

I see, thank you!

@Pascal4QM Thanks it is useful!

@Carl Love 

When f (specific expression) is very complicated, in order to write concisely

@Carl Love  

 

I understand now, thank you so much! Indeed,It can be generated by the transpositions (2, 3) and (3, 4)!

 
 
 
 

@dantopa   When we use the following code, we will get the right output. The example from vv.

I post  another problem of ChromaticNumber in the link below. 

 https://www.mapleprimes.com/questions/229567-Bug-Of-ChromaticNumber

graphsof4c := [NonIsomorphicGraphs(4, output = graphs, outputform = graph,
             restrictto=connected)]:
DrawGraph(graphsof4c [5]);
ChromaticNumber(graphsof4c[5])

 

@tomleslie Thanks and maybe you are right. I still not know  immanent cause.

@Carl Love  Extremely grateful

@Carl Love  Thank you very much!  Unfortunately,I am not still familiar for creating  Array inside loop.  I have a question :  How to save these graphs  based on  using  iterator codes rather than naive method of building lists inside loop.

.

@Carl Love  Thanks!  By testing in my computer, your codes cost 0.375 seconds .  My codes cost 0.672 seconds .

It's much better!   I read the help of  NonIsomorphicGraphs. I noticed one  option output=iterator . 

 For output=iterator a module is returned. When called as a procedure, it outputs the next graph in the sequence. The iterator output is similar to the graphs output, but the complete sequence of graphs is never actually formed, which makes this most useful when dealing with a large number of graphs.
 

 So I use output=iterator in order to avoid costing large RAM when complete sequence of graphs  is formed at once.  Sometimes it  even causes Maple  to crash.

 

@vv  Maple 2020 can do that!

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