Re: [ublas] Matrix Size/ Memory

From: Markus Weimer (markus.weimer_at_[hidden])
Date: 2008-01-28 18:06:31

Hi,

> > There is only one restriction: size1 * size2 has to fit into the size_t
> > type. Thus you need at least a 64-Bit machine to address all matrix
> > entries.
> >
> Does this restriction apply in the case of compressed_matrix?
>

My guess is: Yes. If you want to address something beyond the 32Bit scale,
you need a size_t which is bigger than 32Bit, regardless whether your matrix
actually holds more entries than can be addressed via a 32 Bit address. If
you want to ask for the element at position 5*10^9, you need a variable that
can hold numbers at least up to 5*10^9, which size_t on an 32 Bit hardware
can't.

Cheers,

Markus