GNU Octave enable-64

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.

For quick starters

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

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

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

More details

To illustrate the limitation this project addresses, consider the following Octave code, to determine the integer size of the BLAS library used by Octave:

clear all;
N = 2^31;
## The following line requires about 8 GB of RAM!
a = b = ones (N, 1, "single");
c = a' * b

If the BLAS library uses 32-bit integers, an error will be thrown:

error: integer dimension or index out of range for Fortran INTEGER type

Otherwise, if the BLAS library uses 64-bit integers, the result is:

c = 2^31 = 2147483648

Note that the test case above usually requires twice the memory, if a and b are not assigned by a = b = .... Note further, that the data type "single" has a precision of about 23 binary bits. In this particular example no rounding errors occur.

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

• OpenBLAS (0.3.9),
• SuiteSparse (5.7.1),
• QRUPDATE (1.1.2),
• ARPACK-NG (3.7.0), and
• GNU Octave (5.2.0)

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.

Debian like distributions (Ubuntu, ...) make SuiteSparse a dependency for GLPK. For this reason, this Makefile can optionally build and install the original GLPK version by calling:

make -j2 glpk 2>&1 | tee log/build_glpk.log

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 aforementioned goals are archived by building and deploying the required libraries in arbitrary directories. The following directories can be set when calling the Makefile:

• ROOT_DIR (default: current directory pwd)
• BUILD_DIR (default: ROOT_DIR)/build) The build directory for each library.
• INSTALL_DIR (default: ROOT_DIR)/install) The library installation directory /usr or /usr/local. If the installation directory is a system directory, the flag SUDO_INSTALL=sudo ensures that the installation operations are performed with elevated privileges.
• SRC_CACHE (default: ROOT_DIR/source-cache) The location for downloaded library sources.

Two typical examples:

make ROOT_DIR=$HOME/some/path

make BUILD_DIR=/tmp \
     INSTALL_DIR=/usr/local SUDO_INSTALL=1 \
     SRC_CACHE=$HOME/Downloads

The internal directory structure relative to ROOT_DIR is:

ROOT_DIR
|-- build          # BUILD_DIR
|    |-- arpack
|    |-- octave
|    +--  ...
|-- install        # INSTALL_DIR
|    |-- bin
|    |-- include
|    +-- lib
+-- source-cache   # SRC_CACHE
     |-- arpack-$(VER).tar.gz
     +--  ...

All required libraries are built according to this pattern:

1. Download the source code archive to SRC_CACHE
2. Extract the source code archive to BUILD_DIR
3. Configure and build the library ensuring 64-bit indices
4. Deploy the library in INSTALL_DIR

Notice: For reducing the required disc space to 1 GB, it is possible to remove the directories BUILD_DIR and SRC_CACHE entirely after a successfully build of this project.

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

Similar works

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-blas64-builder by Mike Miller. A typical case of "I should have known earlier about it!" :wink:

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.

Shared libraries and debugging techniques

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.

Environment variables

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.

Useful tools

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