I desperately need to reduce the memory it is using. ... I cannot easily change how it is constructed.

If you cannot change how it is constructed, you cannot reduce the memory that will be used as it is constructed.

You could reduce it after the fact by packing the doubles into a string: 

perl -MDevel::Size=total_size 
-le"@a= map rand(),1..1e6; print total_size \@a; $b=pack'd*', @a; prin
+t total_size( $b )"
40000176
8000056

[download]

That's a 5 to 1 reduction. It will free up memory for other things if you then undef'd the array, but it usually won't release memory back to the OS.

And the individual elements can be accessed and modified use substr in conjunction with pack & unpack. The penalty is loops run more slowly. PDL would be much quicker.

It would be much better if you could avoid the creation of the array in the first place

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

In reply to Re^3: Bizarre Array Size Disparity by BrowserUk
in thread Bizarre Array Size Disparity by sunmaz

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