WIP: Classical groups. Express elements in LGO (nice) generators.#293
WIP: Classical groups. Express elements in LGO (nice) generators.#293danielrademacher wants to merge 4 commits intogap-packages:masterfrom
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I am not keen on adding binaries like PDFs into this repository. There is also the copyright issue (I have not yet looked at them). Also .DS_Store files should not be in there (perhaps add those to a global .gitignore list, on Mac's they can otherwise creep in quite easily.
| Print("The element g is not an element of one of the classical groups in their natural representation. \n"); | ||
| Print("Abort."); |
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Hmm, why not an error?
| Print("The element g is not an element of one of the classical groups in their natural representation. \n"); | |
| Print("Abort."); | |
| Error("The element g is not an element of one of the classical groups in their natural representation"); |
| # Originally implemented subfunctions | ||
| #################### | ||
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| InfoBruhat := NewInfoClass("InfoBruhat");; |
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| InfoBruhat := NewInfoClass("InfoBruhat");; | |
| DeclareInfoClass("InfoBruhat"); |
As a general rule of thumb: a regular GAP file should never include double semicolons; if it does, something is wrong :-)
| a := 0; | ||
| while res mod 2 = 0 do | ||
| a := a + 1; | ||
| res := Int(res*0.5); |
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Another rule of thumb: if you use floating point in GAp other than for printing some statistics, something is wrong.
Here, you should have used either
| res := Int(res*0.5); | |
| res := res / 2; |
which works since you know res is divisible by 2; or in situations where you also want to divde odd numbers by 2 and round down, use QuoInt.
But actually, do neither, and instead replace that whole loop by a := PValuation(n-1, 2);.
| Error("LGOStandardGens: d has to be at least 6\n"); | ||
| return; |
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Never end an Error message with newline. And don't follow it by areturn(the control flow ends here. Well, technically the user can try to edit values and resume execution, but then let them; doing areturnwill break that case. If you really want to prevent it, useErrorNoReturn`, although personally, I see no need for that).
| Error("LGOStandardGens: d has to be at least 6\n"); | |
| return; | |
| Error("LGOStandardGens: d has to be at least 6"); |
| return __LGOStandardGensSOCircle(d,q); | ||
| fi; | ||
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| Error("e has to be 1, -1 or 0."); |
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Also, don't end error messages with a period
| Error("e has to be 1, -1 or 0."); | |
| Error("e has to be 1, -1 or 0"); |
| w := PrimitiveElement(fld); | ||
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| s := IdentityMat( d, fld ); | ||
| s[1][1] := Zero(fld); |
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Ideall use the new syntax for element access everywhere:
| s[1][1] := Zero(fld); | |
| s[1,1] := Zero(fld); |
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Include functions to express arbitrary elements in terms of LGO generators. We use the LGO generators as "nice" generators for the constructive recognition of classical groups.