Re: Strange memory problem

[thompson(at)orpheus.nascom.nasa.gov (William Thompson)]

"Julie Greenwood" <julieg@NOSPAMoceanweather.com> writes:

>Liam Gumley <Liam.Gumley@ssec.wisc.edu> wrote in message
>3860E331.C4E36EA4@ssec.wisc.edu">news:3860E331.C4E36EA4@ssec.wisc.edu...
>> "Mark D. Williams" wrote:
>> > FWIW, if you want to save time and memory, a faster way to do the above
>> > is as follows:
>> >
>> > WAVE> temp = BYTARR(1000,1000,25, /NoZero) + 10B
>>
>> I get the fastest response (in IDL) with
>>
>> temp = replicate(10B, 1000, 1000, 25)
>>
>> Cheers,
>> Liam.


>With IDL 5.3 on WinNT I got:

>temp = BYTARR(1000,1000,25, /NoZero) + 10B
>       1.8230000 Seconds

>temp = replicate(10B, 1000, 1000, 25)
>       6.3290000 Seconds


>I got tired of waiting (more than two minutes) for

>temp=bytarr(1000,1000,25)               ; 0.351 seconds for this much
>temp(*)=10


I suggest redoing the test with

	temp = BYTARR(1000,1000,25) + 10B

with the /NoZero keyword you get a much faster response, but nonsense values.
It's not really a fair test.

On my AlphaStation 500/333, I got the following times:

temp = BYTARR(1000,1000,25) + 10B
       1.8984600 Seconds

temp = replicate(10B, 1000, 1000, 25)
       1.2076780 Seconds

temp=bytarr(1000,1000,25)
temp(*)=10
       9.2365350 Seconds

temp=bytarr(1000,1000,25)
temp(*)=10b
       8.4264030 Seconds

Bill Thompson