Rewriting in black box classical groups Intrinsic 'ClassicalRewrite'

Contains the Magma implementation of several algorithms that write an element of a classical group as an SLP in the standard generators.

Signatures:

(G::Grp, gens::SeqEnum, type::MonStgElt, dim::RngIntElt, q::RngIntElt, 
g::GrpElt) -> BoolElt, GrpElt
[
    Method
]

    The group G must be isomorphic to the classical group given by the 
    argument type, dim, and q; gens must be a generating set of G that 
    satisfies ClassicalStandardPresentation( type, dim, q ); g must be an 
    element in the same universe as the generators of G; the string type is 
    one of "SL", "Sp", "SU", "Omega", "Omega+", "Omega-". The function 
    checks if g is an element of G and returns true or false accordingly. 
    Further, if g is in G, then the function also returns a straight-line 
    program from gens to g. The algorithm employed in the function depends 
    on whether G is given in its natural representation, in a matrix 
    representation over a field in the defining characteristic (grey-box), 
    or in some other representation that that does not fall under the 
    previous cases (black-box). The optional parameter Method may be 
    supplied to override the default choice of algorithm. The possible 
    values of Method are "BB" (to force that the black-box algorithm be 
    used) or "CharP" (to force the grey-box algorithm). If g is not an 
    element of G, then the program attempts to find an SLP that points to an
    element of h such that gh^-1 centralises G. If such an SLP is found that
    the function returns false and this SLP.