On 12/30/2016 02:26 PM, PhilipNienhuis wrote:
John W. Eaton wrote
With this changeset
http://hg.savannah.gnu.org/hgweb/octave/rev/21707d6a02c7
the --enable-64 configure option is now the default. Here's the NEWS
entry:
** On systems with 64-bit pointers, --enable-64 is now the default and
Octave always uses 64-bit indexing.
What will be the anticipated effects for MXE cross-builds? (if any?)
Will -enable-windows-64 still work? (is it still needed?)
Yes, because without that, the compiler is configured to use 32-bit
pointers. We will have the following options:
** 32-bit pointers and indexing (--disable-windows-64):
You are limited to a total of 2^32 bytes of memory
no matter how you slice it. [A]
** 64-bit pointers (--enable-windows-64) three four additional options:
32-bit indexing (--disable-64): Individual array
dimensions are limited to about 2^31 elements but
you can allocate more than one, up to the system
memory limits. You should be able to use a BLAS
library that uses 64-bit integers for indexing, but
you won't be able to take advantage of the larger
array capability of the libraries, so I'm not counting
this as a reasonable possibility.
64-bit indexing (--enable-64) and 32-bit BLAS, LAPACK, etc.:
You are limited to a total of 2^64 bytes of memory and
array dimensions may be up to 2^63 elements but libraries
that use 4-byte integers for indexing will have smaller
limits. [B]
64-bit indexing (--enable-64) and 64-bit BLAS, LAPACK, etc.:
Same array limits as the previous option, but without the
smaller limits for BLAS, LAPACK, etc. Some libraries like
glpk and Qhull that use "int" may still have smaller limits.
[A] is still the default if you don't use either --enable-windows-64 or
--enable-64 when configuring mxe-octave.
[B] should be the default now if you use --enable-windows-64 but not
--enable-64 when configuring mxe-octave. If you use --enable-64 you
will get the last option above (everything possible is built with 64-bit
indexing).
It might make sense to split the meaning of the mxe-octave configure
script's --enable-64 into two options:
--enable/disable-64:
Just set the option for Octave's configure script
--enable-fortran-integer-8:
Build BLAS, LAPACK, etc. using 8-byte INTEGER values by default
Also, I just noticed that the mxe-octave build disables Qhull when using
--enable-64. I'm not sure why, though maybe we just haven't done the
work needed to impose limits on any integer values and arrays that are
passed to Qhull functions? I guess it would be worth checking that out
for both Qhull and glpk.