|
First session with GAP
|
Remember that GAP is case-sensitive!
Do not panic if you see Error, Variable: 'FuncName' must have a value.
Care about names of variables and functions.
Use command line editing.
Use autocompletion instead of typing names of functions and variables in full.
Use ? and ?? to view help pages.
Set the default help format to HTML using SetHelpViewer.
Use the LogTo function to save all GAP input and output into a text file.
If calculation takes too long, press -C to interrupt it.
Read ‘A First Session with GAP’ from the GAP Tutorial.
|
|
Some more GAP objects
|
GAP has a plethora of various immediate, positional and component objects.
List arithmetic is very flexible and powerful.
Objects like lists and records are good to keep structured and related data.
|
|
Functions in GAP
|
Command line is good for prototyping; functions are good for repeated calculations.
Informative function names and comments will make code more readable to your future self and to others.
Beware of undeclared local variables!
|
|
Using regression tests
|
It is easy to create a test file by copying and pasting a GAP session.
Writing a good and comprehensive test suite requires some effort.
Make it right, then make it fast!
|
|
Small groups search
|
Organise the code into functions.
Create small groups one by one instead of producing a huge list of them.
Using SmallGroupsInformation may help to reduce the search space.
GAP is not a magic tool: theoretical knowledge may help much more than the brute-force approach.
|
|
Attributes and Methods
|
Positional objects may accumulate information about themselves during their lifetime.
This means that next time the stored information may be retrieved at zero cost.
Methods are bunches of functions; GAP’s method selection will choose the most efficient method based on the type of all arguments.
‘No-method-found’ is a special kind of error with useful debugging tools helping to understand it.
|