Skip to content

PIConGPU domain definitions

Jump to bottom Edit New page
f-schmitt-zih edited this page May 13, 2014 · 19 revisions

You are here: Home > Developer Documentation > PIConGPU domain definitions

Current naming scheme

This page describes the internal naming scheme for domain and window offsets and sizes in PIConGPU as described in this issue.

Selections

  • domain = contiguous volume on one or all GPUs
  • window = any part of a domain

Selection members

member type notes
.size uint size of an object
.offset int offset of an object to its next higher hierarchy
  • offsets are exclusive and always relative to the element that is above it in the hierarchy

Naming Hierarchy

  • local = the object is located on the current ("my") GPU, no guards
  • global = the currently simulated volume over all GPUs, no guards
  • total = takes parts into account that are not in the global volume, e.g. previous areas that have been gone due to the sliding window

Resulting semantics

  • global:
    • globalDomain.size = size of currently simulation volume on all GPUs
    • globalDomain.offset = offset caused due to slides: offset to the totalDomain
    • globalWindow.size = size of the current/selected moving window (cutting away areas of the globalDomain that are before/after the window)
    • globalWindow.offset = offset of moving window from the first GPU: offset to the globalDomain
  • local:
    • localDomain.size = size of my GPU
    • localDomain.offset = beginning of my local domain in the global Domain
    • localWindow.size = size of the volume of the moving window on my GPU
    • localWindow.offset = offset of my moving window part from the start of the global window

Special use cases

  • My GPU is not contained in the moving window.
    • localWindow.size == 0
    • localWindow.offset == undefined
  • An interface, lets say the gasProfiles, may needs an inclusive domain offset like
    • localDomain.offset+globalDomain.offset (1)
    • how to name the result (1) in the interface?
    • suggestion: localDomainToTotal = (1)
    • note: usually, as defined above, localDomain means localDomainToGlobal because global is the next higher hierarchy.

Old naming scheme (deprecated)

  • domainSize: size of the simulation grid for a GPU

  • domainOffset: offset of the simulation grid of a GPU within the total simulation grid

  • globalDomainSize: size of the currently computed part of the simulation grid (moving window)

  • globalDomainOffset: offset of the currently computed part of the simulation grid (moving window) within the total simulation grid

  • localDomainOffset: offset of the simulation grid of a GPU from the start of the currently computed part (moving window). 0 for all GPUs for which domainOffset > globalDomainOffset

In the below image, the currently computed part of the simulation grid (moving window) is marked as a hatched area. Note that for simulations which do not use moving window, the currently computed part of the simulation grid always spans the total simulation grid.

All wiki entries describe the dev branch. Features may be different in the current master branch.

Before you start please read our README!

PIConGPU is a scientific project. If you present and/or publish scientific results that used PIConGPU, you should set a reference to show your support. Our according up-to-date publication at the time of your publication should be inquired from:

The documentation in this wiki is still not complete and we need your help keeping it up to date. Feel free to help improving this wiki!

Add a custom sidebar

Clone this wiki locally