1. 26 Oct, 2017 1 commit
    • Christopher Subich's avatar
      Simplified tridiangonal solve algorithm; timing extensions · 3581d1c1
      Christopher Subich authored
      First and most trivially, this change adds a few more timing push/pop
      invocations relating to multigrid and especially to some of the MPI
      synchronization steps that might cause processors to wait on each other.
      
      More substantively, this change also adds a new tridiangonal solver
      based on the bog-standard forwards/backwards elimination Thompson
      algorithm (see Wikipedia).  This should be acceptable because the 1D
      problems being solved themselves come from a 2D problem, so we don't
      expect ill-conditioning; calling out to the GMRES banded solver was
      surprisingly a computational bottleneck perhaps because of pivoting.
      
      This change seems to decrease the line-solve time by about 80%, which in
      turn decreases the overall runtime (tank_rho test case) by 40%.
      3581d1c1
  2. 26 Jun, 2017 1 commit
    • Christopher Subich's avatar
      Stack-structured timing code · 0a4781c9
      Christopher Subich authored
      This commit adds stack-structured timing code, such that bits of SPINS
      can be instrumented with
      
      >  timing_push("short name")
      >  [... work goes here]
      >  timing_pop()
      
      This is recursive, such that already-timed portions of the code can call
      the timing code to further instrument subroutines or discrete code
      segments, and the resulting structure follows the -dynamic- call stack.
      This does have the odd result that portions of the code that are re-used
      (namely spectral derivatives) can show up as several 'leaf' nodes in the
      graph.
      
      To print out the report to standard error, call
      
      >  timing_stack_report()
      
      The exact format of the report should be considered tentative.
      0a4781c9
  3. 15 Jun, 2017 1 commit
  4. 18 Sep, 2015 2 commits