{"action":"created","issue":{"url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/1","labels_url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/1/labels{/name}","comments_url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/1/comments","events_url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/1/events","html_url":"https://github.com/tbreloff/Unums.jl/issues/1","id":98170476,"number":1,"title":"Pick the specification","user":{"login":"tbreloff","id":933338,"avatar_url":"https://avatars.githubusercontent.com/u/933338?v=3","gravatar_id":"","url":"https://api.github.com/users/tbreloff","html_url":"https://github.com/tbreloff","followers_url":"https://api.github.com/users/tbreloff/followers","following_url":"https://api.github.com/users/tbreloff/following{/other_user}","gists_url":"https://api.github.com/users/tbreloff/gists{/gist_id}","starred_url":"https://api.github.com/users/tbreloff/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/tbreloff/subscriptions","organizations_url":"https://api.github.com/users/tbreloff/orgs","repos_url":"https://api.github.com/users/tbreloff/repos","events_url":"https://api.github.com/users/tbreloff/events{/privacy}","received_events_url":"https://api.github.com/users/tbreloff/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/tbreloff/Unums.jl/labels/brainstorming","name":"brainstorming","color":"eb6420"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":3,"created_at":"2015-07-30T13:35:21Z","updated_at":"2015-07-30T14:02:58Z","closed_at":null,"body":"In Gustafson's book (End of Errors), he proposes the basic unum:\r\n```\r\n| signbit | exponent | fraction | ubit | esize-1 | fsize-1 |\r\n```\r\nDiscuss: is there a better ordering to these fields to make common operations and compression/decompression more efficient and/or easier to implement?\r\n\r\n\r\nIn addition, he proposes a more complicated, fixed-width spec on p. 100:\r\n```\r\n| negative? | NaN? | Inf? | 0? | 2nd? | exponent | revealedbit | fraction | ubit | esize-1 | fsize-1 |\r\n```\r\n\r\nI think we should discuss a __software__ implementation using fixed-width unums:\r\n- Is this the best ordering of fields?\r\n- Should we throw out the esize/fsize fields and instead have the spec define the number of bits for the exponent and the total size of the structure?  (We would implicitly calculate the size of the fraction by filling in the rest of the available space).  The advantage is more usable space for precision/accuracy.  Are there disadvantages I'm not considering?\r\n- Can we get rid of the revealed bit?  I think we can... I get the impression he put that there just to fill in the 64th bit."},"comment":{"url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/comments/126338531","html_url":"https://github.com/tbreloff/Unums.jl/issues/1#issuecomment-126338531","issue_url":"https://api.github.com/repos/tbreloff/Unums.jl/issues/1","id":126338531,"user":{"login":"ScottPJones","id":11798751,"avatar_url":"https://avatars.githubusercontent.com/u/11798751?v=3","gravatar_id":"","url":"https://api.github.com/users/ScottPJones","html_url":"https://github.com/ScottPJones","followers_url":"https://api.github.com/users/ScottPJones/followers","following_url":"https://api.github.com/users/ScottPJones/following{/other_user}","gists_url":"https://api.github.com/users/ScottPJones/gists{/gist_id}","starred_url":"https://api.github.com/users/ScottPJones/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ScottPJones/subscriptions","organizations_url":"https://api.github.com/users/ScottPJones/orgs","repos_url":"https://api.github.com/users/ScottPJones/repos","events_url":"https://api.github.com/users/ScottPJones/events{/privacy}","received_events_url":"https://api.github.com/users/ScottPJones/received_events","type":"User","site_admin":false},"created_at":"2015-07-30T14:02:58Z","updated_at":"2015-07-30T14:02:58Z","body":"Ah, that would be fine, for me, best if they are all in one place, so I just don't store them when I pack numbers, and can recreate them upon unpacking (because space in the DB or memory is the biggest determinant of performance for me)"}}