New Lattice.reduce method

[lfarv]

The Lattice.reduce method is similar to the atreduce Matlab function: it removed all elements with an IdentityPass passmethod, and then merges compatible consecutive elements.

A keep keyword allows to keep selected elements even if they have an IdentityPass passmethod. By default, Lattice.reduce keeps Monitor and RFCavity elements.

[swhite2401]

This is very nice!

[lfarv]

@simoneliuzzo : there was a bug when comparing PolynomA/B (missing the last term, PolynomB[MaxOrder]). Your example now seems to run. Can you check ?

[simoneliuzzo]

I have tested with two lattice files. One EBS SR lattice, with few elements to reduce and an ARC cell of 10000 elements that has been correctly reduced to 141 elements. The optics after reducing are identical a part the last few digits of some parameters (numerical).

[lfarv]

@simoneliuzzo: thanks for testing, I rely on you for that !

Did you try "keep=None" which should be even more agressive by removing Monitor and RFCavity elements, or any other "keep" combination ?

[simoneliuzzo]

Dear @lfarv ,
no I did not try, I find that is a very good idea to keep RF and BPMs by default.
Now I tried it.
On a very segmented ARC cell it gives no errors and the optics are identical to those of the default reduce. So, good for me.
On an EBS SR lattice with RF cavities it works without issues. I think the cavities are CavityPass (or RFCavityPass) and thus they are not removed.

[lfarv]

@simoneliuzzo:

I think the cavities are CavityPass (or RFCavityPass) and thus they are not removed.

Of course, this is useful only if radiation is OFF: thin cavities are then set to IdentityPass.