Cross-Compiling Armadillo Linear Algebra Library

Question

I enjoy using the Armadillo Linear Algebra Library. It becomes extremely nice when porting octave .m files over to C++, especially when you have to use the eigen methods.

Answer 1

My specific setup is OSX (IDE Eclipse) cross compiled to a Beaglebone Black. However, these instructions should work for similar setups.

Optional:

For compiling I used the Mac OS X ARM GNU Linux G++ Lite 2013.11-33 Toolchain. Specifically, the ARM GNU/Linux G++ Lite 2013.11-33 Advanced Binary.

1. Download:

Just as Matt posted, the GCC cross compiler doesn't support Fortran, so if you want to compile LAPACK and BLAS, use a modified version found here. I'm using is clapack-3.2.1-CMAKE.tgz

2. Make a cross compile cmake file:

You can use a toolchain builder or just write one. I wrote one.

Example:

# http://www.cmake.org/Wiki/CMake_Cross_Compiling#The_toolchain_file

# REQUIRED
SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_SYSTEM_VERSION 1)
SET(CMAKE_SYSTEM_PROCESSOR arm)

# Added for the beaglebone
SET(FLOAT_ABI_SUFFIX "")

# specify the cross compiler
SET(CMAKE_C_COMPILER   /usr/local/arm-2013.11/bin/arm-none-linux-gnueabi-gcc)
SET(CMAKE_CXX_COMPILER /usr/local/arm-2013.11/bin/arm-none-linux-gnueabi-c++)

# where is the target environment 
SET(CMAKE_FIND_ROOT_PATH  /usr/local/arm-2013.11)

# search for programs in the build host directories
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

Note: This is my first time making a cmake file. It isn't guaranteed to be correct.

You'll want to replace /usr/local/arm-2013.11/bin/arm-none-linux-gnueabi-gcc with the path to your selected compiler, as well as /usr/local/arm-2013.11/bin/arm-none-linux-gnueabi-c++ and /usr/local/arm-2013.11

I chose to save this cmake file as beaglebone.cmake

3. Compile:

Extract clapack-3.2.1-CMAKE.tgz and cd

compile: cmake -DCMAKE_TOOLCHAIN_FILE=~/Dropbox/workspaces/beaglebone/beaglebone.cmake
where ~/Dropbox/workspaces/beaglebone/beaglebone.cmake is the path to your cmake file.

make

For some sort of reason I get:

ds-mac-pro:clapack-3.2.1-CMAKE bunny$ make
Scanning dependencies of target arithchk
[  0%] Building C object F2CLIBS/libf2c/CMakeFiles/arithchk.dir/arithchk.c.o
Linking C executable arithchk
[  0%] Built target arithchk
[  0%] Generating arith.h
/bin/sh: arithchk: command not found
make[2]: *** [F2CLIBS/libf2c/arith.h] Error 127
make[1]: *** [F2CLIBS/libf2c/CMakeFiles/f2c.dir/all] Error 2
make: *** [all] Error 2

Oddly, running make again compiles fine:

ds-mac-pro:clapack-3.2.1-CMAKE bunny$ make
[  0%] Built target arithchk
Scanning dependencies of target f2c
[  0%] Building C object F2CLIBS/libf2c/CMakeFiles/f2c.dir/f77vers.c.o
[  0%] Building C object F2CLIBS/libf2c/CMakeFiles/f2c.dir/i77vers.c.o
[  0%] Building C object F2CLIBS/libf2c/CMakeFiles/f2c.dir/main.c.o
[  0%] Building C object F2CLIBS/libf2c/CMakeFiles/f2c.dir/s_rnge.c.o

...

[100%] Building C object TESTING/EIG/CMakeFiles/xeigtstz.dir/xerbla.c.o
[100%] Building C object TESTING/EIG/CMakeFiles/xeigtstz.dir/xlaenv.c.o
[100%] Building C object TESTING/EIG/CMakeFiles/xeigtstz.dir/chkxer.c.o
[100%] Building C object TESTING/EIG/CMakeFiles/xeigtstz.dir/__/__/INSTALL/dsecnd.c.o
Linking C executable xeigtstz
[100%] Built target xeigtstz

4. Copy (Install):

find . | grep \.a$

returns

./BLAS/SRC/libblas.a
./F2CLIBS/libf2c/libf2c.a
./SRC/liblapack.a
./TESTING/MATGEN/libtmglib.a

cp libblas.a libf2c.a and liblapack.a to your favorite library folder. I made /usr/local/armadillo-4.300.3/lib

Required:

1. Copy Includes:

Armadillo doesn't need to be compiled. I haven't ran any benchmarks to verify, but it appears that using LAPACK and BLAS works fine with an uncompiled copy of Armadillo by using #define in code. Code examples later.

extract armadillo-4.300.3.tar.gz

(optional) cp armadillo-4.300.3/include/ /usr/local/armadillo-4.300.3/include
and of course, replace /usr/local/armadillo-4.300.3/include with your path of choice

2. Setup GCC to use Armadillo:

I'm using Eclipse with the C/C++ Cross Compiler Support addon (Help Menu -> Install New Software...), but the instructions are easy to convert to cli or other IDEs.

In the project properties window: C/C++ Build -> Settings

Cross G++ Compiler -> Includes -> Include paths (-I)

Click the + to add an include. My include path is: /usr/local/armadillo-4.300.3/include

3. OPTIONAL - Setup GCC to use the compiled libraries:

Cross G++ Linker -> Libraries ->

Libraries (-l)

lapack
f2c
blas

Library Search Path (-L)

Click the + to add a path. My path is: /usr/local/armadillo-4.300.3/lib

3. Code Example:

In a cpp file try:

#include 
using namespace arma;

mat A = randu(4,5);
mat B = randu(4,5);

std::cout << A*B.t() << std::endl;

Success! :D

Some functionality Armadillo does not directly support and will only work with compiled libraries. You can test that the libraries are compiled and working correctly by running a simple test like:

#define ARMA_DONT_USE_WRAPPER
#define ARMA_USE_LAPACK
#define ARMA_USE_BLAS
#include 
using namespace arma;

mat    A = randu(5,5);
double x = det(A);

std::cout << x << std::endl;