how to create 2d arrays of large size ?

Sanju Singh

11y1.6k

hello, i wish to know can i create 2D arrays of double datatype with large size like 120,000 X120,000? I came to know that in .net the upper bound on index in any single dimension is 2,147,483,591 (0x7FFFFFC7) for byte arrays. because of this i get an error saying memory not sufficient. any help. your inputs will be of great value to me.

thank you

3 Replies

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Sanju Singh11y ago
thanks Vulpes. I am already working on these lines.
Vulpes11y ago
Well, each double requires 8 bytes of memory and so a 2D double array of the size you mentioned will need:

120,000 x 120,000 x 8 = 115,200,000,000 bytes

which is more than 107 gigabytes!

As memory is normally limited to 2 GB in 32 bit .NET applications, having such a huge array in memory is clearly out of the question and you therefore need to look at breaking it up into more manageable chunks.

If you're loading the data into the array from a file, a suitable chunk might be 120 rows which would require a more manageable:

120 x 120,000 x 8 = 115,200,000 bytes which is approx 110 MB.

So, if you declare your array to be of size 120 x 120000, you can keep on refilling the same array after you've processed each chunk until the file is exhausted.
sumit kumar11y ago
Please have a look on below links

http://codereview.stackexchange.com/questions/48211/declaring-a-large-number-of-2d-arrays-to-be-used-as-2d-graphic-sprites

http://stackoverflow.com/questions/9571290/create-big-two-dimensional-array