[FLASH-BUGS] "minor" glitch in flatten.F90 (part 2)

From: Markus Gross (m.s.gross@hw.ac.uk)
Date: Wed Jul 16 2003 - 07:33:44 CDT

  • Next message: Tomasz Plewa: "Re: [FLASH-BUGS] "minor" glitch in flatten.F90"

    Hi again!

    Realizing that my fix was not much better than the original for any non
    constructed case, i.e. when rounding error may be present, may I suggest the
    following:

    !this is the original:
    !!$ if (dp(i) .LT. 0.e0) then
    !!$ scrch2(i) = scrch3(i+1)
    !!$ else
    !!$ scrch2(i) = scrch3(i-1)
    !!$ endif

    !my "new" suggestion:
           if (dp(i) .LT. -10.e0) THEN
              scrch2(i) = scrch3(i+1)
           ELSE
              if (dp(i) .GT. 10.e0) THEN
                 scrch2(i) = scrch3(i-1)
              ELSE
                 weight1 = 0.5d0*dabs(derf(dp(i)+2.d0)-1.d0)
                 weight2 = 0.5d0*dabs(derf(dp(i)-2.d0)+1.d0)
                 scrch2(i) = scrch3(i+1) * weight1 +&
                             scrch3(i-1) * weight2 +&
                             scrch3(i ) * (1.d0-(weight1+weight2))
              END IF
           END IF

    This of course assumes that a -2.d0< dp(i) < 2.d0 is effectively a dp(i)=0
    which for my case is true. Modifications for other "small" values is of course
    straight forward.

    Again, what do you think? A weibull may of course be faster than the erf...

    Regards,

    Markus.

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