Section Calculation Modes::Optimal Control
When doing QOCT with the conjugate-gradient optimization scheme, the gradient is computed thanks to a forward-backwards propagation. For debugging purposes, this gradient can be compared with the value obtained "numerically" (i.e. by doing successive forward propagations with control fields separated by small finite differences).
In order to activate this feature, set OCTCheckGradient to some non-zero value,
which will be the finite difference used to numerically compute the gradient.
call parse_variable(namespace, 'OCTCheckGradient', CNST(0.0), oct%check_gradient)