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Re: Maximum index for arrays? [message #62562 is a reply to message #62559]

Mon, 15 September 2008 03:15

hotplainrice@gmail.co is currently offline

hotplainrice@gmail.co
Messages: 15
Registered: July 2008

Junior Member

On Sep 15, 6:53 pm, Chris <beaum...@ifa.hawaii.edu> wrote:
> On Sep 14, 8:08 pm, "hotplainr...@gmail.com" <hotplainr...@gmail.com>
> wrote:
>
>
>
>> Hi guys,
>
>> Thanks for helping me for the past few weeks. I've managed to get
>> CUBLAS and other CUDA programs working in IDL. What I have now for you
>> guys is this.
>
>> Here is the code
>
>> N = 181
>> N2 = N^2
>> a = fltarr(N2, 141)
>> help,a
>
>> A FLOAT = Array[32761, 141]
>
>> N = 182
>> N2 = N^2
>> a = fltarr(N2, 141)
>> % Array dimensions must be greater than 0
>> % Execution halted at: TEST 5 /home/hpr/test.pro
>> % $MAIN$
>> IDL>
>
>> How big can the index go? Its because I need N = 100 to 1000
>
>> Regards
>> Zaki
>
> The problem is that the line
> N = 182
> sets N to a 16-bit signed integer (max size 32767-ish). When you
> square it (33124), it overflows and becomes negative (-32412). Use
> something like
> N=182L (long integer with max size about 2 billion) or
> N=2. (floating point)
>
> As long as you have the RAM, arrays can have millions or billions (i
> think) of elements, so you'll be fine.
>
> chris

Thanks chris, that resolved the problem.

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[Message index]

		Re: Maximum index for arrays? By: pgrigis on Mon, 15 September 2008 06:38
		Re: Maximum index for arrays? By: hotplainrice@gmail.co on Mon, 15 September 2008 03:15
		Re: Maximum index for arrays? By: Chris[6] on Mon, 15 September 2008 01:53

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