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Home » MIDRANGE-L » December 2001

RE: array handling



fixed

> -----Original Message-----
> From: jt
>
> But you said ASCEND causes a binary search...?!?  Sheesh...  When did THAT
> happen...?!?  (I'd always thought it still used sequential search, and
> ASCEND just allowed for *LT or *GT type lookups.)  That'd be two things,
> today...:-)

I have to eat a substantial bit of crow here, JT.  I did the one thing I
hate most - I typed in an assumption as fact.  I was told this way back in
the early days of my programming career, and I honestly never bothered to
check it, I assumed it was so because it made such good sense.  It made
sense to me that IBM, with all their knowledge in writing compilers, would
indeed be smart enough to use something as fundamentally sound as a binary
search algorithm, but this turns out not to be true, at least from empirical
evidence.

Modifying my test program to compare the times of a lookup on an acending
array and a lookup on a non-ascending array yielded exactly the same
results, even after 5,000,000 repetitions.  In my copious free time, I might
try to check the generated MI code, but the actual test shows me that the
code is exactly the same for each one.

Just trying to set the record straight.







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