Search found 10 matches
- 02 Aug 2022, 09:27
- Forum: HowTos and FAQ for TeNPy
- Topic: UserWarnings differ for identical initializations when run several times
- Replies: 1
- Views: 3401
UserWarnings differ for identical initializations when run several times
I have a frequent issue with UserWarning s regarding unused options in as such that they differ for identical(?) code, run several times. Typically this happens when initializing some tenpy algorithm. E.g.: import logging logging.basicConfig(level=logging.INFO) # allow for some UserWarnings # Next, ...
- 29 Jul 2022, 12:30
- Forum: HowTos and FAQ for TeNPy
- Topic: My correlation functions from MPS.correlation_function and MPSEnvironment.expectation value disagree
- Replies: 2
- Views: 3253
Re: My correlation functions from MPS.correlation_function and MPSEnvironment.expectation value disagree
Aah! Now I do get C_a = C_b for my system. Great. Thx. (I was trying to interpret the list of strings from the 2nd figure in tenpy.networks.mps.MPS.correlation_function following the description of correlation_function , which kind of suggested to someone=me, lost in the very helpful docs, that the ...
- 29 Jul 2022, 09:58
- Forum: HowTos and FAQ for TeNPy
- Topic: My correlation functions from MPS.correlation_function and MPSEnvironment.expectation value disagree
- Replies: 2
- Views: 3253
My correlation functions from MPS.correlation_function and MPSEnvironment.expectation value disagree
Hello, I have issues, calculation correlation functions of 2-site operators in different ways. Before posting a lot of specific code, let me pls. ask in a more general context: Let |\psi\rangle be an MPS of finite even length L Let A_i B_{i+1} denote a nearest neighbor 2-site operator, i.e. some npc...
- 31 Mar 2022, 14:17
- Forum: HowTos and FAQ for TeNPy
- Topic: MPS winding for 'new' lattice
- Replies: 2
- Views: 3972
Re: MPS winding for 'new' lattice
Ok., so I may have come a little step further, but I'd still be glad if 'some higher power' would kick in to let me know if I'm at least heading into the right direction. To be more specific, the 2D lattice I'm looking at has more than 2 sites per unit cell and I want to have my own way of traversin...
- 30 Mar 2022, 15:22
- Forum: HowTos and FAQ for TeNPy
- Topic: MPS winding for 'new' lattice
- Replies: 2
- Views: 3972
MPS winding for 'new' lattice
Hi, I am trying to implement a 2D lattice not available yet. I am fine up until the ordering function in lattice.py . The way how this function works, or if at all I need to tweak this particular function, or something else in order to set up my own winding for a new 2D lattice is unclear to me. I'v...
- 09 Jun 2021, 10:41
- Forum: HowTos and FAQ for TeNPy
- Topic: Random UserWarning: unused option ['P_tol']
- Replies: 1
- Views: 8032
Random UserWarning: unused option ['P_tol']
I frequently and randomly get the warning UserWarning: unused option ['P_tol'] for config lanczos_params warnings.warn(msg.format(keys=sorted(unused), name=self.name)) when starting a dmrg run. I get this warning independent of if I do , or if I do not use 'lanczos_params': {'P_tol': some integer,} ...
- 09 Jun 2021, 10:21
- Forum: HowTos and FAQ for TeNPy
- Topic: If/How to avoid: "final DMRG state not in canonical form..."
- Replies: 4
- Views: 6944
Re: If/How to avoid: "final DMRG state not in canonical form..."
Thx. for replying! I did already spend a lot more time playing around, and indeed, 'my' model has a parameter range to which your suggestion Do you have multiple degenerate ground states? exactly applies. I was unaware of that property :o . I.e, tenpy gave me a gentle hint :oops: Stupidly, I was run...
- 24 May 2021, 10:17
- Forum: HowTos and FAQ for TeNPy
- Topic: If/How to avoid: "final DMRG state not in canonical form..."
- Replies: 4
- Views: 6944
If/How to avoid: "final DMRG state not in canonical form..."
I'm trying to run finite system dmrg on a spin model with multi-site exchange, i.e. with coupling terms of type J_{\alpha_1\dots\alpha_r} S^{\alpha_1}_{i_1}\dots S^{\alpha_r}_{i_r} . In my case, I can have r=2,4,6 spins involved. The Hamiltonian is hermitean. I should clearly state, that I'm a noob ...
- 23 Apr 2021, 20:47
- Forum: HowTos and FAQ for TeNPy
- Topic: Chain with N site unit-cell
- Replies: 2
- Views: 3023
Re: Chain with N site unit-cell
As usual, I couldn't wait, and tried some more. Let me pls. add to my question and get more specific. For the sake of brevity, let me assume that in my OP I set \(A_{l,j}=S_x\). Moreover at the risk of crucifixion, let me forget all about charge conservation, boundary conditions and other 'details'....
- 23 Apr 2021, 08:37
- Forum: HowTos and FAQ for TeNPy
- Topic: Chain with N site unit-cell
- Replies: 2
- Views: 3023
Chain with N site unit-cell
Hello, this is a stupid newbie's question. Most certainly, the answer I'm looking for is just a pointer to a location in the existing documentation. I'd be grateful for that. I'm trying to implement a model that lives on a chain and has more than a single site per unit cell. So, e.g. for 2 sites per...