[plt-scheme] Float Vectors and Unsafe Operations

From: Doug Williams (m.douglas.williams at gmail.com)
Date: Mon May 17 09:23:50 EDT 2010

I had expected flvectors to be more efficient at the time, too. And was
surprised when they weren't. But I did have the wrong mental model of
flvector versus fl64vector. Thanks for explaining it.

On Mon, May 17, 2010 at 3:36 AM, Noel Welsh <noelwelsh at gmail.com> wrote:

> On Mon, May 17, 2010 at 4:22 AM, Doug Williams
> <m.douglas.williams at gmail.com> wrote:
> > 1) Would we expect the flvector (or fl64vector) implementations to be
> more
> > efficient now? Or, at sometime in the (near) future?
> That's odd. I would expect flvectors to be more efficient than vectors of
> reals.
> > 2) I assume flvectors are 32-bit floats and fl64vectors are 64-bit
> floats.
> > Is this correct? Is there any significant difference in efficiency of one
> > over the other - particularly wrt unsafe operations?
> flvectors are doubles -- they store inexact reals, which by default
> are doubles (64-bits) but can be floats (32-bits) if you compile
> MzScheme with the right flags. flvectors should be faster than
> fl64vectors -- they avoid an indirection according to the docs.
> HTH,
> N.
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