{"action":"created","issue":{"url":"https://api.github.com/repos/netket/netket/issues/67","repository_url":"https://api.github.com/repos/netket/netket","labels_url":"https://api.github.com/repos/netket/netket/issues/67/labels{/name}","comments_url":"https://api.github.com/repos/netket/netket/issues/67/comments","events_url":"https://api.github.com/repos/netket/netket/issues/67/events","html_url":"https://github.com/netket/netket/pull/67","id":358059868,"node_id":"MDExOlB1bGxSZXF1ZXN0MjEzOTIyNDE2","number":67,"title":"Introduced Lanczos ED from IETL library","user":{"login":"alexwie","id":5948847,"node_id":"MDQ6VXNlcjU5NDg4NDc=","avatar_url":"https://avatars3.githubusercontent.com/u/5948847?v=4","gravatar_id":"","url":"https://api.github.com/users/alexwie","html_url":"https://github.com/alexwie","followers_url":"https://api.github.com/users/alexwie/followers","following_url":"https://api.github.com/users/alexwie/following{/other_user}","gists_url":"https://api.github.com/users/alexwie/gists{/gist_id}","starred_url":"https://api.github.com/users/alexwie/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/alexwie/subscriptions","organizations_url":"https://api.github.com/users/alexwie/orgs","repos_url":"https://api.github.com/users/alexwie/repos","events_url":"https://api.github.com/users/alexwie/events{/privacy}","received_events_url":"https://api.github.com/users/alexwie/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":0,"created_at":"2018-09-07T13:06:53Z","updated_at":"2018-09-07T14:17:40Z","closed_at":null,"author_association":"COLLABORATOR","pull_request":{"url":"https://api.github.com/repos/netket/netket/pulls/67","html_url":"https://github.com/netket/netket/pull/67","diff_url":"https://github.com/netket/netket/pull/67.diff","patch_url":"https://github.com/netket/netket/pull/67.patch"},"body":"Dear all, \r\n\r\nI wrote a wrapper for using the IETL Lanczos code (http://alps.comp-phys.org/static/doc2.1.0/ietl.html). The ground state energy computation in NetKet would now be done with this library. Probably we should discuss some more detailed user interface for the algorithm (how to set parameters, like precision for the Lanczos iteration. There are also some test, which could be extended. \r\n\r\nBest,\r\nAlex"},"comment":{"url":"https://api.github.com/repos/netket/netket/issues/comments/419453770","html_url":"https://github.com/netket/netket/pull/67#issuecomment-419453770","issue_url":"https://api.github.com/repos/netket/netket/issues/67","id":419453770,"node_id":"MDEyOklzc3VlQ29tbWVudDQxOTQ1Mzc3MA==","user":{"login":"gcarleo","id":28149892,"node_id":"MDQ6VXNlcjI4MTQ5ODky","avatar_url":"https://avatars0.githubusercontent.com/u/28149892?v=4","gravatar_id":"","url":"https://api.github.com/users/gcarleo","html_url":"https://github.com/gcarleo","followers_url":"https://api.github.com/users/gcarleo/followers","following_url":"https://api.github.com/users/gcarleo/following{/other_user}","gists_url":"https://api.github.com/users/gcarleo/gists{/gist_id}","starred_url":"https://api.github.com/users/gcarleo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gcarleo/subscriptions","organizations_url":"https://api.github.com/users/gcarleo/orgs","repos_url":"https://api.github.com/users/gcarleo/repos","events_url":"https://api.github.com/users/gcarleo/events{/privacy}","received_events_url":"https://api.github.com/users/gcarleo/received_events","type":"User","site_admin":false},"created_at":"2018-09-07T14:17:40Z","updated_at":"2018-09-07T14:17:40Z","author_association":"CONTRIBUTOR","body":"Thanks @alexwie , excellent work! The Lanczos part integrates very nicely via the IETL, and diagonalising a 20 spins Hamiltonian takes about 20 seconds on my laptop, which seems a pretty good performance to me.  \r\n\r\nDo we have tests on complex hamiltonians? In the 'GroundState' section of the input I would allow the user to chose among two different methods 'SparseEd' and 'FullEd'. Then, you can easily retrieve custom Lanczos parameters from the input, but I would maybe leave the current values as default values? Is there a warning or something similar if the Lanczos is not converged within the given number of iterations? \r\n\r\nSomething we should also think about is how to work with the Observables in the case of ED. @femtobit already did some work in the context of Imaginary time propagation, and I guess that could be easily exported also to the 'SparseEd' case"}}
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