This projects purpose is to compile GNU Octave with some of it's library dependencies consistently using 64-bit indices on Linux systems. The GNU Octave manual describes this problem in more detail.

If all GNU Octave build dependencies are installed, just type the following commands:

git clone https://github.com/siko1056/GNU-Octave-enable-64.git
cd GNU-Octave-enable-64
make -j2 2>&1 | tee build.log
./install/bin/octave

In case of any problems, a detailed log of all console output is saved to build.log this way.

In particular, a Makefile is provided containing all necessary information to compile

• OpenBLAS (0.2.20),
• SuiteSparse (5.1.2),
• QRUPDATE (1.1.2),
• ARPACK-NG (3.5.0), and
• GNU Octave (4.2.1)

using 64-bit indices. To get a quick overview about the library dependencies, the following figure visualizes them top-down: "The above requires all libraries below".

+-------------------------------------------------------+
|                     GNU Octave                        |
+-------------+-------------+-------------+-------------+
|             | SuiteSparse |  QRUPDATE   |  ARPACK-NG  |
|             +-------------+-------------+-------------+
| OpenBLAS                                              |
+-------------------------------------------------------+

Notice: It is assumed, that the user of this Makefile is already capable of building the "usual" Octave development version!

Means, that all other GNU Octave build dependencies (e.g. libtool, gfortran, ...) are properly installed on the system and, even better, building the "usual" Octave development version runs flawless. Building this project requires approximately 5 GB disc space and 1 hour, depending on your system and the number of parallel jobs make -j.

Using this Makefile is especially of interest, if one pursues the following goals:

1. No root privileges required.
2. No collision with system libraries.

Both abovementioned goals are archived by building and deploying the required libraries in an arbitrary directory ROOT_DIR. This directory can be set by calling the Makefile like:

make ROOT_DIR=$HOME/some/path

The internal directory structure relative to ROOT_DIR is:

ROOT_DIR
|-- build          # local build directory for each library
|    |-- arpack
|    |-- octave
|    +--  ...
|-- install        # local installation path like `/usr` or `/usr/local`
|    |-- bin
|    |-- include
|    +-- lib
+-- source-cache   # location for downloaded library sources
     |-- arpack-$(VER).tar.gz
     +--  ...

All required libraries are built according to this pattern:

1. Download the source code
2. Extract the source code to directory ROOT_DIR/build
3. Configure and build the library (sometimes with ugly hacks)
   1. Ensure usage of 64-bit indices.
   2. Ensure the suffix _Octave64 in the library's SONAME.
4. Deploy the library in ROOT_DIR/install (sometimes with ugly hacks)

Notice: For reducing the required disc space to 1 GB, it is possible to remove the directory ROOT_DIR/build entirely after a successfully build of this project.

To guarantee the usage of the self compiled libraries, even in presence of a system wide installed substitute, the library's SONAME is changed to enforce a hard error if the "wrong" library is taken. Therefore it would even be possible to deploy the self compiled libraries system wide. The SONAME can be set by calling the Makefile like:

make SONAME_SUFFIX=
make SONAME_SUFFIX=Octave64

The first call leaves the library names unchanged, while the second call adds the suffix _Octave64 to each library, which is the default behavior. For more information on shared libraries in common Linux distributions, see the subsection below.

For more information on the topic of building GNU Octave using large indices, see the GNU Octave manual or the GNU Octave wiki.

This project is greatly inspired by a blog post by Richard Calaba, who created one year ahead a GitHub repository for GNU Octave 3.8.

A very similar project to this one is octave-64-bit-index-builder by Mike Miller. A typical case of "I should have known earlier about it!" :wink:

For Windows, there is a cross-compiling solution, called MXE-Octave. It compiles all dependencies from scratch, thus requires much more disc space and time than this approach.

As all of this project deals with the correct treatment of shared libraries, it follows a short review on how to work with them and debug their usage.

A method to ensure that shared libraries located in a certain folder are found, is to export the system environment variable LD_LIBRARY_PATH. In the example below, the environment variable gets extended by the path /opt/lib.

export LD_LIBRARY_PATH=/opt/lib:$LD_LIBRARY_PATH
./run-your-program

Another very verbose method to figure out what shared libraries your system is actually loading and at which paths your system is looking for them, is exporting the system environment variable LD_DEBUG:

export LD_DEBUG={files|bindings|libs|versions|help}
./run-your-program

The meaning of the individual values of LD_DEBUG can be found at tldp.org.

Some useful tools for checking the shared library dependencies of a program or library or whether the "right" shared library was loaded at runtime by a program are:

• ld - The GNU linker
• ldd - print shared library dependencies
• nm - list symbols from object files
• objdump - display information from object files
• pmap - report memory map of a process
• readelf - Displays information about ELF files.

Assume your program binary is called <PROG> and at runtime it has the process ID <PID> (which can for example be found out with pgrep -l octave) and a shared library of interest is called <LIB>, then the commands can be used as follows:

ldd        {<PROG>|<LIB>}
nm -D      {<PROG>|<LIB>}
objdump    {<PROG>|<LIB>}
readelf -d {<PROG>|<LIB>}
pmap       <PID>

To get a further insight into shared libraries, here are some more advanced references on this topic:

• tldp.org
• yolinux.com
• ibm.com