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## The Performance Test Applications

Under boost-path/libs/math/reporting/performance you will find some reasonable comprehensive performance test applications for this library.

In order to generate the tables you will have seen in this documentation (or others for your specific compiler) you need to invoke `bjam` in this directory, using a C++11 capable compiler. Note that results extend/overwrite whatever is already present in boost-path/libs/math/reporting/performance/doc/performance_tables.qbk, you may want to delete this file before you begin so as to make a fresh start for your particular system.

The programs produce results in Boost's Quickbook format which is not terribly human readable. If you configure your user-config.jam to be able to build Docbook documentation, then you will also get a full summary of all the data in HTML format in boost-path/libs/math/reporting/performance/html/index.html. Assuming you're on a 'nix-like platform the procedure to do this is to first install the `xsltproc`, `Docbook DTD`, and `Bookbook XSL` packages. Then:

- Copy boost-path/tools/build/example/user-config.jam to your home directory.
- Add `using xsltproc ;` to the end of the file (note the space surrounding each token, including the final ";", this is important!) This assumes that `xsltproc` is in your path.
- Add `using boostbook : path-to-xsl-stylesheets : path-to-dtd ;` to the end of the file. The `path-to-dtd` should point to version 4.2.x of the Docbook DTD, while `path-to-xsl-stylesheets` should point to the folder containing the latest XSLT stylesheets. Both paths should use all forward slashes even on Windows.

At this point you should be able to run the tests and generate the HTML summary, if GSL, RMath or libstdc++ are present in the compilers path they will be automatically tested. For DCDFLIB you will need to place the C source in boost-path/libs/math/reporting/performance/third_party/dcdflib.

If you want to compare multiple compilers, or multiple options for one compiler, then you will need to invoke `bjam` multiple times, once for each compiler. Note that in order to test multiple configurations of the same compiler, each has to be given a unique name in the test program, otherwise they all edit the same table cells. Suppose you want to test GCC with and without the -ffast-math option, in this case bjam would be invoked first as:

    bjam toolset=gcc -a cxxflags=-std=gnu++11

Which would run the tests using default optimization options (-O3), we can then run again using -ffast-math:

    bjam toolset=gcc -a cxxflags='-std=gnu++11 -ffast-math' define=COMPILER_NAME='"GCC with -ffast-math"'

In the command line above, the -a flag forces a full rebuild, and the preprocessor define COMPILER_NAME needs to be set to a string literal describing the compiler configuration, hence the double quotes - one for the command line, one for the compiler.