[NumPy-Tickets] [NumPy] #2077: Incorrect finfo from PPC longdouble

[NumPy Trac]

#2077: Incorrect finfo from PPC longdouble
---------------------------+------------------------------------------------
 Reporter:  matthew.brett  |       Owner:  somebody   
     Type:  defect         |      Status:  new        
 Priority:  normal         |   Milestone:  Unscheduled
Component:  Other          |     Version:  devel      
 Keywords:                 |  
---------------------------+------------------------------------------------
 {{{

 In [1]: import numpy as np

 In [2]: print np.finfo(np.longdouble)
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:125: RuntimeWarning:
 overflow encountered in add
   a = a + a
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:127: RuntimeWarning:
 invalid value encountered in subtract
   temp1 = temp - a
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:136: RuntimeWarning:
 invalid value encountered in subtract
   itemp = int_conv(temp-a)
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:160: RuntimeWarning:
 overflow encountered in add
   a = a + a
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:162: RuntimeWarning:
 invalid value encountered in subtract
   temp1 = temp - a
 /Users/mb312/dev_trees/numpy/numpy/core/machar.py:169: RuntimeWarning:
 invalid value encountered in subtract
   if any(temp-a != zero):
 Machine parameters for float128
 ---------------------------------------------------------------------
 precision= 75   resolution= 1e-75
 machep=    -4   eps=        1.3817869701e-76
 negep =    -4   epsneg=     1.3817869701e-76
 minexp=    -1   tiny=       -1.08420217274e-19
 maxexp=     1   max=        -9.22337203471e+18
 nexp  =     1   min=        -max
 ---------------------------------------------------------------------


 In [3]: print np.finfo(np.longdouble).nmant
 1

 In [4]: np.__version__
 Out[4]: '1.7.0.dev-aae5b0a'
 }}}

 I think the correct answers for nexp, nmant are 11, 106 respectively; see:
 https://developer.apple.com/library/mac/#documentation/Darwin/Reference/Manpages/man3/float.3.html

 {{{
 (np-devel)[mb312@jerry ~]$ uname -a
 Darwin jerry.bic.berkeley.edu 8.11.0 Darwin Kernel Version 8.11.0: Wed Oct
 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC Power Macintosh
 powerpc
 (np-devel)[mb312@jerry ~]$ gcc -v
 Using built-in specs.
 Target: powerpc-apple-darwin8
 Configured with: /var/tmp/gcc/gcc-5370~2/src/configure --disable-checking
 -enable-werror --prefix=/usr --mandir=/share/man --enable-
 languages=c,objc,c++,obj-c++ --program-transform-
 name=/^[cg][^.-]*$/s/$/-4.0/ --with-gxx-include-dir=/include/c++/4.0.0
 --with-slibdir=/usr/lib --build=powerpc-apple-darwin8 --host=powerpc-
 apple-darwin8 --target=powerpc-apple-darwin8
 Thread model: posix
 gcc version 4.0.1 (Apple Computer, Inc. build 5370)
 }}}

-- 
Ticket URL: <http://projects.scipy.org/numpy/ticket/2077>
NumPy <http://projects.scipy.org/numpy>
My example project