[GAP Forum] Strange output

[Stephen Linton]

Hi Gordon,

Could you let me have your programme so I can look into this?

In terms of correctness, though, this is not a bug. The range [1,6..11] which has length 3 offset 1 and step 5 is equal to the plain list [1,6,11].  GAP range notation only makes sense with the brackets and the three entry notation [a,b..c] implies a step of b-a. b..c does not mean anything outside brackets.

As Laurent says, GAP in general, is allowed to, and benefits by being able to, choose what representation to return a result in, so long as the result is correct according to the documentation.

If there isn't a good performance reason, though, then this is needless complication, so I'll look into it. 

	Steve

On 8 Feb 2013, at 09:10, Gordon Royle <Gordon.Royle at uwa.edu.au> wrote:

> I have a simple program that uses SmallestImageSet to find the lex least representative of orbits of a graph on k-sets.
> 
> The output has suddenly started to look odd, in that in among all the "regular" sets, there are sets that print out with a strange syntax
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> [ 1, 5, 51 ]
> [ 1, 6 .. 11 ]
> [ 1, 6, 12 ]
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> The set [ 1, 6 .. 11 ] is equal to [1, 6, 11] but why does it print this way?
> 
> Thanks
> 
> Gordon
> 
> Professor Gordon Royle
> School of Mathematics and Statistics
> University of Western Australia
> Gordon.Royle at uwa.edu.au<mailto:Gordon.Royle at uwa.edu.au>
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