Function: mfatkineigenvalues
Section: modular_forms
C-Name: mfatkineigenvalues
Prototype: GLb
Help: mfatkineigenvalues(mf,Q): Only applies to mf output by mfsplit corresponding to
 a split space, and for (trivial or) quadratic characters defined modulo N/Q.
 Outputs the Atkin-Lehner eigenvalues of the eigenforms for the primitive
 divisor Q of the level. The result is +-1 in even weight and +-i in odd weight.
Doc: Let $Q$ be a primitive divisor of the level $N$, and let \kbd{mf} be a
 split space for (trivial or) quadratic characters defined modulo $N/Q$.
 Outputs the Atkin-Lehner eigenvalues of the eigenforms for the primitive
 divisor $Q$ of the level. The result is always $\pm1$ in even weight, and
 also $\pm i$ in odd weight.
 \bprog
 ? mf = mfsplit([35,2]); mfatkineigenvalues(mf,5)
 %1 = [[1], [-1, -1]]
 ? CHI = Mod(3,4); mf = mfsplit([12,7,CHI]);
 ? mfatkineigenvalues(mf,3)
 %3 = [[-I, I, -I, I, -I, I]]
 @eprog
