[GRASS-dev] output of doubles as text

Glynn Clements glynn at gclements.plus.com
Fri Aug 14 22:06:44 EDT 2009

Hamish wrote:

> "i.e. can we always assume DCELL|double to be the same bit depth,
> and %.15g the most we'll ever be able to squeeze from it?"
> perhaps that's poorly worded: not that DCELL == double, but that
> size(double) in one place == size(double) in another.

We can assume that it always refers to IEEE 754 double precision
format. Systems where this isn't the case are extremely uncommon, and
will almost certainly fail to support GRASS without a great deal of
additional effort.

And regardless of the precision of "double", I seriously doubt that
anyone has actual data which is accurate to 15 significant digits
(equivalent to specifying the circumference of the earth to within 40
nanometres, or the height of Everest to within 9 picometres).

Glynn Clements <glynn at gclements.plus.com>

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