SpinDynamics.org User Support Forum

Dear Prof. Kuprov,

Is it possible to optimize an effective propagator using the optimal control module?

If I want to optimize a cyclic propagator (unit matrix), is it feasible to define the problem in Spinach?

Best regards,
Mengjia

that's absolutely good news for me, thank you for implementing this fancy algorithm！

thank you so much, I am lucky to try new features.

Dear Ilya, to cover the resonance bandwidth, I found the optimal control example in the Spinach defined multiple spins for the spin system and built a large-size Hamiltonian. Another method I can come up with is to build a small-size spin system but put the bandwidth into ensembles (control.drifts)....

thanks for your quick reply.

Best,
Mengjia

Dear Ilya, To analyze the pulse sequence, I'm considering calculating the Hamiltonian in the Interaction Frame, which is defined by the H_rf (RF part)+H_z (Zeeman part), since there is a big offset. So the effective J coupling part (H_J) should be rotated in this frame, is there any function to calc...

thanks for the update, I will try and hope David would do that

I'm excited to give this method a try ASAP since LBFGS taking its time to converge in my simulation. But of course, it all depends on your schedule. Many thanks!

Dear Prof. Kuprov, you may find David Goodwin's new paper regarding Accelerated Newton-Raphson GRAPE methods for optimal control, which shows very impressive acceleration in the computation of the Hessian, in a large number of time steps. So do you have a plan to include the new features in this pap...

Dear Prof. Kuprov, I'm considering running the optimal control under a given gradient field, i.e., applying RF and gradient pulse simultaneously. In this case, the gradient pulse is known but shaped. To include the gradient in optimal control, I guess it's difficult to contribute the gradient to a d...