Function: mfparams
Section: modular_forms
C-Name: mfparams
Prototype: G
Help: mfparams(F): Returns [N,k,CHI], level, weight, and character:
 F is either a modular form space or a modular form; in the latter case
 the level N may be a multiple of the level of F.
Doc: Returns \kbd{[N,k,CHI]}, level, weight, and character:
 $F$ is either a modular form space  or a modular form; in the latter case
 the level $N$ may be a multiple of the level of $F$. If you want the true
 level of $F$ from this result, use \kbd{mfconductor(mfinit([N,k,CHI]),F)}.
 \bprog
 ? E1 = mfeisen(4,-3,-4); E2 = mfeisen(3,5,-7); E3 = mfmul(E1,E2);
 ? E4 = mfderivE2(E3,3);
 ? apply(params, [E1,E2,E3,E4])
 %1 = [[12, 4, 12], [35, 3, -35], [420, 7, -420], [420, 13, -420]]
 @eprog In the case of a modular form $F$ which was created via a recipe
 for its coefficients (\kbd{mfcreate}), if the level, weight or character
 cannot be determined, they are set to the impossible values
 $-1$, $-1$ or $0$ respectively.
