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samuel2015 / sparsehash

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Documentation `Resource use' incorrect for 64-bit pointer architecture #36

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
In the documentation `Implementation notes' under the section `Resource
use', it states:

The space overhead for an sparsetable of size N is N + 48N/M bits. For the
default value of M, this is exactly 2 bits per array entry.

This statement is true for architectures with a 32-bit pointer. For an
architecture with a 64-bit pointer, the overhead is
N + 80N/M bits
and for the default value of M=48, the overhead is 8/3 or 2.67 bits per entry.

Cheers,
Shaun

Original issue reported on code.google.com by sjackman on 4 Mar 2009 at 12:41

GoogleCodeExporter commented 9 years ago 
Good point.  I'll fix the documentation for the next release.

Original comment by csilv...@gmail.com on 4 Mar 2009 at 8:56

GoogleCodeExporter commented 9 years ago 
This should be fixed in sparsehash 1.5, just released.

Original comment by csilv...@gmail.com on 7 May 2009 at 3:10