TwoQubitBasisDecomposer.decomp2_supercontrolled

TwoQubitBasisDecomposer.decomp2_supercontrolled(target)

Decompose target ~Ud(x, y, z) with 2 uses of the basis gate.

For supercontrolled basis ~Ud(pi/4, b, 0), all b, result Ur has trace .. math:

|Tr(Ur.Utarget^dag)| = 4cos(z)

which is the optimal approximation for basis of CNOT-class ~Ud(pi/4, 0, 0) or DCNOT-class ~Ud(pi/4, pi/4, 0) and any target. May be sub-optimal for b!=0 (e.g. there exists exact decomposition for any target using B B~Ud(pi/4, pi/8, 0), but not this decomposition.) This is an exact decomposition for supercontrolled basis and target ~Ud(x, y, 0). No guarantees for non-supercontrolled basis.