[Numpy-tickets] [NumPy] #730: long doubles display differently than the other float types
NumPy
numpy-tickets@scipy....
Wed Apr 9 18:09:54 CDT 2008
#730: long doubles display differently than the other float types
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Reporter: charris | Owner: somebody
Type: defect | Status: new
Priority: normal | Milestone: 1.0.5
Component: Other | Version: none
Severity: minor | Resolution:
Keywords: |
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Comment (by charris):
These values should really be determined at compile time, not hardwired in
at lines 611-621 of scalartypes.inc.src. Maybe use the values in float.h,
which on my machine give
{{{
single digits 6
double digits 15
long double digits 18
}}}
The current values we are using are 8, 17, and 22 whereas the values above
are supposed to guarantee reversible conversion to and from decimal. Of
course, that doesn't seem to be the case in practice, they seem to need at
least one more digit. The other question is if all the common compilers
support float.h
The numbers above were generated by
{{{
#include <float.h>
#include <stdio.h>
int main(int argc, char** argv)
{
printf("single digits %d\n",FLT_DIG);
printf("double digits %d\n",DBL_DIG);
printf("long double digits %d\n",LDBL_DIG);
return 1;
}
}}}
--
Ticket URL: <http://scipy.org/scipy/numpy/ticket/730#comment:1>
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