Changes between Version 3 and Version 4 of Status/May11


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Timestamp:
Apr 20, 2011 12:30:45 PM (3 years ago)
Author:
igloo
Comment:

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  • Status/May11

    v3 v4  
    6262'''Manuel: Any status update? Previous entry below''' 
    6363 
    64   Since the last report, we have continued to improve support for nested parallel divide-and-conquer algorithms.  We started with [[http://darcs.haskell.org/packages/dph/dph-examples/spectral/QuickHull/dph/QuickHullVect.hs QuickHull]] and are now working on an implementation of the [[http://darcs.haskell.org/packages/dph/dph-examples/real/BarnesHut/Solver/NestedBH/Solver.hs Barnes-Hut]] ''n''-body algorithm.  The latter is not only significantly more complex, but also requires the vectorisation of recursive tree data-structures, going well beyond the capabilities of conventional parallel-array languages.  In time for the stable branch of GHC 7.0, we replaced the old, per-core sequential array infrastructure (which was part of the sub-package `dph-prim-seq`) by  the [[http://hackage.haskell.org/package/vector vector package]] — vector started its life as a next-generation spin off of `dph-prim-seq`, but now enjoys significant popularity independent of DPH.  
     64  ''Since the last report, we have continued to improve support for nested parallel divide-and-conquer algorithms.  We started with [[http://darcs.haskell.org/packages/dph/dph-examples/spectral/QuickHull/dph/QuickHullVect.hs QuickHull]] and are now working on an implementation of the [[http://darcs.haskell.org/packages/dph/dph-examples/real/BarnesHut/Solver/NestedBH/Solver.hs Barnes-Hut]] ''n''-body algorithm.  The latter is not only significantly more complex, but also requires the vectorisation of recursive tree data-structures, going well beyond the capabilities of conventional parallel-array languages.  In time for the stable branch of GHC 7.0, we replaced the old, per-core sequential array infrastructure (which was part of the sub-package `dph-prim-seq`) by  the [[http://hackage.haskell.org/package/vector vector package]] — vector started its life as a next-generation spin off of `dph-prim-seq`, but now enjoys significant popularity independent of DPH.'' 
    6565 
    66   The new handling of INLINE pragmas as well as other changes to the Simplifier improved the stability of DPH optimisations (and in particular, array stream fusion) substantially.  However, the current candidate for GHC 7.0.1 still contains some performance regressions that affect the DPH and [[http://hackage.haskell.org/package/repa Repa]] libraries and to avoid holding up the 7.0.1 release, we decided to push fixing these regressions to GHC 7.0.2.  More precisely, we are planning a release of DPH and Repa that is suitable for use with GHC 7.0 for the end of the year, to coincide with the release of GHC 7.0.2.  From GHC 7.0 onwards, the library component of DPH will be shipped separately from GHC itself and will be available to download and install from Hackage as for other libraries. 
     66  ''The new handling of INLINE pragmas as well as other changes to the Simplifier improved the stability of DPH optimisations (and in particular, array stream fusion) substantially.  However, the current candidate for GHC 7.0.1 still contains some performance regressions that affect the DPH and [[http://hackage.haskell.org/package/repa Repa]] libraries and to avoid holding up the 7.0.1 release, we decided to push fixing these regressions to GHC 7.0.2.  More precisely, we are planning a release of DPH and Repa that is suitable for use with GHC 7.0 for the end of the year, to coincide with the release of GHC 7.0.2.  From GHC 7.0 onwards, the library component of DPH will be shipped separately from GHC itself and will be available to download and install from Hackage as for other libraries.'' 
    6767 
    68   To catch DPH performance regressions more quickly in the future, Ben Lippmeier implemented a performance regression testsuite that we run nightly on the HEAD.  The results can be enjoyed on the GHC developer mailing list. 
     68  ''To catch DPH performance regressions more quickly in the future, Ben Lippmeier implemented a performance regression testsuite that we run nightly on the HEAD.  The results can be enjoyed on the GHC developer mailing list.'' 
    6969 
    70   Sadly, Roman Leshchinskiy has given up his full-time engagement with DPH to advance the use of Haskell in the financial industry.  We are looking forward to collaborating remotely with him. 
     70  ''Sadly, Roman Leshchinskiy has given up his full-time engagement with DPH to advance the use of Haskell in the financial industry.  We are looking forward to collaborating remotely with him.'' 
    7171 
    7272