[Numpy-discussion] float128 / longdouble on PPC - is it broken?

Matthew Brett matthew.brett@gmail....
Tue Oct 25 14:13:39 CDT 2011


Hi,

On Tue, Oct 25, 2011 at 12:01 PM, Derek Homeier
<derek@astro.physik.uni-goettingen.de> wrote:
> On 25 Oct 2011, at 20:05, Matthew Brett wrote:
>
>>>> Both the same as numpy:
>>>>
>>>> [mb312@jerry ~]$ gcc test.c
>>>> test.c: In function 'main':
>>>> test.c:5: warning: incompatible implicit declaration of built-in function
>>>> 'powl'
>>>
>>> I think implicit here means that that the arguments and the return values
>>> are treated as integers. Did you #include <math.h>?
>>
>> Ah - you've detected my severe ignorance of c.   But with math.h, the
>> result is the same,
>>
>> #include <stdio.h>
>> #include <math.h>
>>
>> int main(int argc, char* argv) {
>>       long double x;
>>       x = pow(2, 64);
>>       x -= 1;
>>       printf("%g %Lg\n", (double)x, x);
>> }
>
> What system/compiler is this? I am getting
> ./ldouble
> 1.84467e+19 1.84467e+19
>
> and
>
>>>> res = np.longdouble(2)**64
>>>> res
> 18446744073709551616.0
>>>> 2**64
> 18446744073709551616L
>>>> res-1
> 18446744073709551615.0
>>>> np.__version__
> '1.6.1'
>
> as well as with
>
>>>> np.__version__
> '2.0.0.dev-3d06f02'
> [yes, not very up to date]
>
> and for all gcc versions
> /usr/bin/gcc -v
> Using built-in specs.
> Target: powerpc-apple-darwin9
> Configured with: /var/tmp/gcc/gcc-5493~1/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=i686-apple-darwin9 --program-prefix= --host=powerpc-apple-darwin9 --target=powerpc-apple-darwin9
> Thread model: posix
> gcc version 4.0.1 (Apple Inc. build 5493)
>
> to
>
> /sw/bin/gcc-fsf-4.6 -v
> Using built-in specs.
> COLLECT_GCC=/sw/bin/gcc-fsf-4.6
> COLLECT_LTO_WRAPPER=/sw/lib/gcc4.6/libexec/gcc/powerpc-apple-darwin9.8.0/4.6.1/lto-wrapper
> Target: powerpc-apple-darwin9.8.0
> Configured with: ../gcc-4.6.1/configure --prefix=/sw --prefix=/sw/lib/gcc4.6 --mandir=/sw/share/man --infodir=/sw/lib/gcc4.6/info --enable-languages=c,c++,fortran,lto,objc,obj-c++,java --with-gmp=/sw --with-libiconv-prefix=/sw --with-ppl=/sw --with-cloog=/sw --with-mpc=/sw --with-system-zlib --x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib --program-suffix=-fsf-4.6 --enable-cloog-backend=isl --disable-libjava-multilib --disable-libquadmath
> Thread model: posix
> gcc version 4.6.1 (GCC)
>
> uname -a
> Darwin osiris.astro.physik.uni-goettingen.de 9.8.0 Darwin Kernel Version 9.8.0: Wed Jul 15 16:57:01 PDT 2009; root:xnu-1228.15.4~1/RELEASE_PPC Power Macintosh

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)
[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

Best,

Matthew


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