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> In article <38E03BDC.868B8396@hotmail.com>, marc <email@example.com> writes:
> >Is there a function like TOTAL but for multiplication.
> >Like the big PI symbol in mathematical notation.
> >Or this really something for the for loop?
> if all the elements of a are positive then you can simply do
> result = exp(total(alog(a)))
> If some of the elements are negative, you can still handle it. do
> dum = where(a lt 0, ndum)
> sig = (-1)^ndum
> result = sig*exp(total(alog(abs(a))))
You can't honestly be suggesting that this is a good technique? Ignore
for a momement what happens if any element of 'a' is 0. That code
performs two transcendental function evaluations per element of 'a'. IDL
would have to be very badly engineered (which I suppose is possible),
for a 'for' loop to execute more slowly than your code.