[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: co2calc.f and ta_iter_1.f
- Subject: Re: co2calc.f and ta_iter_1.f
- From: email@example.com ("E.Maier-Reimer")
- Date: Mon, 19 Jul 1999 17:20:34 +0200 (MET DST)
that is not true
It depends, of course on the amount of chemical changes
since the previous computation.
two or three iterations are suffient for roundoff error
on a 64-bit machine. Practically, one iteration would
be sufficient, indeed.
some reminders for optimization:
(trivial) call of subroutines should be done with arrays
not with single variables for vectorization
the choice of phhi and phlo is rather irrelevant
once you are at 10**(-8) the iteration will hardly touch
the bounds. For crazy starting values it is sufficient
to ensure that htotal does not come below , say, 10 %
of the previous guess
It may be more efficient to do 3 iterations for the whole array
than than to perform sophisticated checking for avoiding redundant
I made the experience that even advenced programmers are not aware
of the fact that sqrt, log, exp sin cos are extremely time consuming.
a**b is even worse
the chemical constants should not have higher temporal resolution
then other fields. I strongly recommend to provide monthly fields
and interpolate for the actual timestep.