Octave load

This article is outdated. For current C++ code examples see the Octave Manual https://octave.org/doc/latest/Standalone-Programs.html.

The code below shows an example of how to load a matrix from a file in Octave's binary file format. An example of how to load data from a file in Octave's ascii format can be found in this page.

Code: octave_binary_io_example.cc: C++ function to load a matrix from a BINARY file in Octave native format

#include <fstream> #include <octave/oct.h> #include <octave/ov.h> #include <octave/zfstream.h> #include <octave/octave.h> #include <octave/parse.h> #include <octave/toplev.h> #include <octave/load-save.h> #include <octave/ls-oct-binary.h> #include <octave/oct-map.h> #include <cstring> std::fstream file; std::ios::openmode m = std::ios::in; load_save_format format = LS_BINARY; oct_mach_info::float_format flt_fmt = oct_mach_info::flt_fmt_unknown; bool swap = false; int main (void) { string_vector argv (1); install_types (); argv(0) = std::string ("test_var"); file.open ("test.bin", m); if (read_binary_file_header (file, swap, flt_fmt, true) != 0) return -1; octave_scalar_map m = do_load (file, "test.bin", format, flt_fmt, false, swap, true, argv, 0, 1, 1).scalar_map_value (); std::cout << m.contents ("test_var").matrix_value (); file.close (); return 0; }

To test, type the following in Octave:

>> test_var = randn(5); >> save -binary test.bin test_var

Compile and run the example with the following commads

$ mkoctfile --link-stand-alone octave_binary_io_example.cc $ ./a.out