{"action":"closed","issue":{"url":"https://api.github.com/repos/JuliaLang/IterativeSolvers.jl/issues/48","labels_url":"https://api.github.com/repos/JuliaLang/IterativeSolvers.jl/issues/48/labels{/name}","comments_url":"https://api.github.com/repos/JuliaLang/IterativeSolvers.jl/issues/48/comments","events_url":"https://api.github.com/repos/JuliaLang/IterativeSolvers.jl/issues/48/events","html_url":"https://github.com/JuliaLang/IterativeSolvers.jl/issues/48","id":106502996,"number":48,"title":"How to supply custom MatVec function to eigvals_lanczos?","user":{"login":"xyu40","id":12038937,"avatar_url":"https://avatars.githubusercontent.com/u/12038937?v=3","gravatar_id":"","url":"https://api.github.com/users/xyu40","html_url":"https://github.com/xyu40","followers_url":"https://api.github.com/users/xyu40/followers","following_url":"https://api.github.com/users/xyu40/following{/other_user}","gists_url":"https://api.github.com/users/xyu40/gists{/gist_id}","starred_url":"https://api.github.com/users/xyu40/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/xyu40/subscriptions","organizations_url":"https://api.github.com/users/xyu40/orgs","repos_url":"https://api.github.com/users/xyu40/repos","events_url":"https://api.github.com/users/xyu40/events{/privacy}","received_events_url":"https://api.github.com/users/xyu40/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-09-15T07:58:02Z","updated_at":"2015-09-26T03:25:35Z","closed_at":"2015-09-26T03:25:35Z","body":"After reading the documentations and the source code (common.jl, krylov,jl, and lanczos.jl), I still have no clues as to how to supply a custom matrix-vector multiplication function to eigvals_lanczos.\r\n\r\nI only figures out how to get linear-operators-defined-as-functions, such as A = MatrixFcn{Float64}(4, 4, mulbyA!). Although this works as matrix-vector multiplication, yet when put in eigvals_lanczos(A) it throws error message: \r\n\"`KrylovSubspace{T,OpT}` has no method matching `KrylovSubspace{T,OpT}(::MatrixFcn{Float64}, ::Int64)`\".\r\n\r\nI will appreciate it greatly if you guys can help me on this."}}