{"action":"created","issue":{"url":"https://api.github.com/repos/mit-crpg/openmc/issues/594","repository_url":"https://api.github.com/repos/mit-crpg/openmc","labels_url":"https://api.github.com/repos/mit-crpg/openmc/issues/594/labels{/name}","comments_url":"https://api.github.com/repos/mit-crpg/openmc/issues/594/comments","events_url":"https://api.github.com/repos/mit-crpg/openmc/issues/594/events","html_url":"https://github.com/mit-crpg/openmc/issues/594","id":136057191,"number":594,"title":"Implement HDF5-Based MGXS Library Format","user":{"login":"nelsonag","id":1037107,"avatar_url":"https://avatars.githubusercontent.com/u/1037107?v=3","gravatar_id":"","url":"https://api.github.com/users/nelsonag","html_url":"https://github.com/nelsonag","followers_url":"https://api.github.com/users/nelsonag/followers","following_url":"https://api.github.com/users/nelsonag/following{/other_user}","gists_url":"https://api.github.com/users/nelsonag/gists{/gist_id}","starred_url":"https://api.github.com/users/nelsonag/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nelsonag/subscriptions","organizations_url":"https://api.github.com/users/nelsonag/orgs","repos_url":"https://api.github.com/users/nelsonag/repos","events_url":"https://api.github.com/users/nelsonag/events{/privacy}","received_events_url":"https://api.github.com/users/nelsonag/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/mit-crpg/openmc/labels/MGXS","name":"MGXS","color":"009800"},{"url":"https://api.github.com/repos/mit-crpg/openmc/labels/Multi-Group%20Mode","name":"Multi-Group Mode","color":"eb6420"}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":23,"created_at":"2016-02-24T13:08:32Z","updated_at":"2016-06-28T16:00:49Z","closed_at":null,"body":"As discussed in #336, it would be nice to have an HDF5-based mgxs input file format.  This can be done in one of two ways:\r\n\r\n1. We just take the current xml format as is and port it to HDF5.\r\n2. Gain some experience with different use cases of the current capability and see if format changes exist which would be more useful.\r\n\r\nI'm open to either an am curious to hear other's opinions.  One facet to consider is if this should be included with 0.8 or not.  If so, that would push us to #1.\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/mit-crpg/openmc/issues/comments/229096004","html_url":"https://github.com/mit-crpg/openmc/issues/594#issuecomment-229096004","issue_url":"https://api.github.com/repos/mit-crpg/openmc/issues/594","id":229096004,"user":{"login":"friedmud","id":870705,"avatar_url":"https://avatars.githubusercontent.com/u/870705?v=3","gravatar_id":"","url":"https://api.github.com/users/friedmud","html_url":"https://github.com/friedmud","followers_url":"https://api.github.com/users/friedmud/followers","following_url":"https://api.github.com/users/friedmud/following{/other_user}","gists_url":"https://api.github.com/users/friedmud/gists{/gist_id}","starred_url":"https://api.github.com/users/friedmud/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/friedmud/subscriptions","organizations_url":"https://api.github.com/users/friedmud/orgs","repos_url":"https://api.github.com/users/friedmud/repos","events_url":"https://api.github.com/users/friedmud/events{/privacy}","received_events_url":"https://api.github.com/users/friedmud/received_events","type":"User","site_admin":false},"created_at":"2016-06-28T16:00:49Z","updated_at":"2016-06-28T16:00:49Z","body":"@nelsonag interesting... but when is the decompression done?  Is it done as the file is read?  Because all of those zeros will still take up a lot of memory...\r\n\r\nEventually I really do want some sort of sparse storage for my XS... both for memory and computation.\r\n\r\nI like the \"format\" that the YakXS guys came up with... it incorporates what we know about the physics: that there is a limited ability for upscatter and there is (possibly) a limit for downscatter.  So, in their format you essentially specify the first column and last column of each row that will have values... and you provide a value for everything in between (keep in mind that YakXS uses \"out on row\" for it's scattering matrices).  It's a very intuitive way to do it that maps well to the physics."}}
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