{"action":"created","issue":{"url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/2703","repository_url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu","labels_url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/2703/labels{/name}","comments_url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/2703/comments","events_url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/2703/events","html_url":"https://github.com/ComputationalRadiationPhysics/picongpu/issues/2703","id":361303889,"node_id":"MDU6SXNzdWUzNjEzMDM4ODk=","number":2703,"title":"Jumps in output data of plugins (in moving window simulations)","user":{"login":"steindev","id":26382442,"node_id":"MDQ6VXNlcjI2MzgyNDQy","avatar_url":"https://avatars3.githubusercontent.com/u/26382442?v=4","gravatar_id":"","url":"https://api.github.com/users/steindev","html_url":"https://github.com/steindev","followers_url":"https://api.github.com/users/steindev/followers","following_url":"https://api.github.com/users/steindev/following{/other_user}","gists_url":"https://api.github.com/users/steindev/gists{/gist_id}","starred_url":"https://api.github.com/users/steindev/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/steindev/subscriptions","organizations_url":"https://api.github.com/users/steindev/orgs","repos_url":"https://api.github.com/users/steindev/repos","events_url":"https://api.github.com/users/steindev/events{/privacy}","received_events_url":"https://api.github.com/users/steindev/received_events","type":"User","site_admin":false},"labels":[{"id":163171179,"node_id":"MDU6TGFiZWwxNjMxNzExNzk=","url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/labels/affects%20latest%20release","name":"affects latest release","color":"e11d21","default":false},{"id":49956691,"node_id":"MDU6TGFiZWw0OTk1NjY5MQ==","url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/labels/bug","name":"bug","color":"fc2929","default":true},{"id":50986606,"node_id":"MDU6TGFiZWw1MDk4NjYwNg==","url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/labels/component:%20plugin","name":"component: plugin","color":"cf6800","default":false}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":1,"created_at":"2018-09-18T13:26:31Z","updated_at":"2018-09-24T07:41:01Z","closed_at":null,"author_association":"CONTRIBUTOR","body":"I recognized in two different kind of simulations with two different plugins jumps in output data of longitudinal (y) quantities. I suspect these are related to calculations of output data within the moving window.\r\n\r\nThe two cases are:\r\n\r\n### Resetting of electron bunch longitudinal position in phase space output of LWFA sims\r\n* picongpu version: 0.4.0rc2\r\n* plugin: e_phaseSpace y-py\r\n\r\nThe electron position in y-direction (laser propagation and moving window direction) is repeatedly reset at a period of about twice the simulation box size in y-direction. Here, electron position resets take place every 3k to 4k (mostly) time steps. The simulation box is 2304 cells in y direction, with 8 gpus along  this direction. The ratio of y cell size to time step is `DY / ( cspeed * DT ) = 1.5275`. That is, it seems like a reset occurs when the moving window moved once over the simulation box, i.e. every `n_reset = 2304 * DY /  ( cspeed * DT ) = 2304 * 1.5275 = 3519` time steps. This value fits to the observed reset period.\r\n![phasespace_ypy](https://user-images.githubusercontent.com/26382442/45493719-b32b1c80-b76f-11e8-9bb4-29c32d48d88c.gif)\r\n\r\n\r\n### Increase in longitudinal E- and B-field energy in field energy plugin\r\n* picongpu version: 0.3.0\r\n* plugin: fields_energy\r\n\r\nThe longitudinal field energy jumps with a period of 20kDT. This time the simulation volume is 8192 cells in y-direction distributed over 16 gpus. The ratio of y cell size to time step is `DY / ( cspeed * DT ) = 0.99976`. \r\n![image](https://user-images.githubusercontent.com/26382442/45688557-fb708300-bb51-11e8-8a24-d07131587333.png)\r\nZoom in to Ey data. Note that the sampling rate is high compared to period length of jumps.\r\n![image](https://user-images.githubusercontent.com/26382442/45688570-00cdcd80-bb52-11e8-8bf5-3ffd978e01ab.png)\r\nAs this second appearance of jumps does not really match the first one I will start a primitive bunch acceleration with piconpu-0.4.0 and see how the fields develop and if this behavior is reproduced.\r\n\r\nStill it is funny that these jumps appear at a time the window needs to pass about twice the simbox."},"comment":{"url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/comments/423896471","html_url":"https://github.com/ComputationalRadiationPhysics/picongpu/issues/2703#issuecomment-423896471","issue_url":"https://api.github.com/repos/ComputationalRadiationPhysics/picongpu/issues/2703","id":423896471,"node_id":"MDEyOklzc3VlQ29tbWVudDQyMzg5NjQ3MQ==","user":{"login":"ax3l","id":1353258,"node_id":"MDQ6VXNlcjEzNTMyNTg=","avatar_url":"https://avatars3.githubusercontent.com/u/1353258?v=4","gravatar_id":"","url":"https://api.github.com/users/ax3l","html_url":"https://github.com/ax3l","followers_url":"https://api.github.com/users/ax3l/followers","following_url":"https://api.github.com/users/ax3l/following{/other_user}","gists_url":"https://api.github.com/users/ax3l/gists{/gist_id}","starred_url":"https://api.github.com/users/ax3l/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ax3l/subscriptions","organizations_url":"https://api.github.com/users/ax3l/orgs","repos_url":"https://api.github.com/users/ax3l/repos","events_url":"https://api.github.com/users/ax3l/events{/privacy}","received_events_url":"https://api.github.com/users/ax3l/received_events","type":"User","site_admin":false},"created_at":"2018-09-24T07:41:01Z","updated_at":"2018-09-24T07:41:01Z","author_association":"MEMBER","body":"Afair, the plugin dumps all but also adds the meta information to slice out the window accordingly. Our Python plugin should do this reliably, so users don't need to fiddle with the HDF5 attributes and the cutting: https://picongpu.readthedocs.io/en/0.4.0-rc2/usage/plugins/phaseSpace.html#analysis"}}
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