Basic HTML version of Foils prepared 17 Sept 1996

Foil 77 Reductions in INDEPENDENT DO Loops

From New CPS615HPF and Fortran90 Discussion Sept 17 96 Basic Simulation Track for Computational Science CPS615 -- Fall Semester 96. by Geoffrey C. Fox, Tom Haupt


Many applications of INDEPENDENT DO loops do require reductions as they are typically calculating independently quantities but storing results as parts of various averages
e.g. in High Enegry Physics Data Analysis, each measured event can be computed via an INDEPENDENT DO but one wishes to find a particular observable (histogram, scatterplot) which is averaged over each event
Financial modelling is similar
x = 0
!HPF$ INDEPENDENT, NEW(xinc), REDUCTION(x)
do i = 1 , N
  • call sub(i, xinc)
  • x = x + xinc
END DO
xinc is a separate new variable each iteration but result is accumulated into global x



© on Tue Oct 7 1997