OMPi -- a portable OpenMP C compiler
Copyright since 2001, University of Ioannina,
Dept. of Computer Science & Engineering
==================================================================

See files AUTHORS and NEWS for contact information.

The file COPYING contains the licence. Make sure you read it first
before using this package.

The file BUGS contains a list of known bugs/limitations.

This file is a (very) quick HOWTO on OMPi. It contains short
sections on installation and usage. Consult the doc/ directory
for more documentation.
  

============================
                          
 QUICK INSTALLATION GUIDE
                          
============================

                          
Requirements:
You must have a standard C compiler (e.g. gcc) and libtool.


1) Extract the package

    gunzip ompi-X.Y.Z.tar.gz
    tar xvf ompi-X.Y.Z.tar
    
2) Configure the package *(see below for more details)

    ./configure --prefix=<install-dir>

3) Compile and install the package

    make
    make install

4) Make sure <install-dir>/bin is in your PATH


For information about the configure script, see INSTALL.

* (Notes on advanced configuring)
  -------------------------------
 
  If you want to enable debugging, give the --enable-debug option
  to ./configure (turned off by default)

  The compiler flags used to build the compiler & the libraries are
  just -O3. More often than not you may want to use different ones
  (such as e.g. -g). In such cases use 
       ./configure CFLAGS=<your_flags> CPPFLAGS=<preprocessor_flags> ...

  The default compiler is determined by configure itself (and is usually
  gcc). If you want to use a different compiler (e.g. Intel's icc), use 
       ./configure CC=icc ...

  The compiler & flags that OMPi will later use for compiling
  your programs are by default the ones used in ./configure time. If
  you want different ones, define OMPI_CC, OMPI_CPP, OMPI_CFLAGS and 
  OMPI_CPPFLAGS environmental variables, before running ompicc, 
  as described below.

  OMPi comes with multiple thread libraries, and can support even more 
  (see doc/runtime.txt); "pthreads", based on POSIX threads, is the 
  default one. You can choose which one OMPi will be built with as 
  follows:
       ./configure --with-ortlib=<name> ...
  where <name> is one of the four, or any other library you have developed.
  
  OMPi can support multiple OpenMP4 devices through device 'modules'; 
  by default, at configuration time it checks and builds all device modules 
  that may be supported. You can choose which ones OMPi should be built with 
  as follows:
       ./configure --with-modules="<name> <name> ..." ...
  i.e. space-seperated module names, where each <name> is any of the
  modules OMPi ships with, or any other module you may have developed.
  


===============
              
 USING OMPi
              
===============


Usage:  ompicc [-k] [-v] [other arguments] <cc-flags> files.c

For example:
    ompicc -o binary file1.c file2.c 

arguments:
    all (g)cc flags
    -k : the generated (transformed) file is kept after compilation
    -v : be verbose (shows all steps of the translation process)
some other arguments:
    --ort=<libname> : use an alternative runtime library (see below)
    --devs=<devices>: target the given devices
    --devinfo: show information about configured devices.
    
OMPi is a source-to-source compiler, so after generating the 
multithreaded C program, it runs the system compiler -- which by 
default is the one used during OMPi's installation. If you want 
to play with different system compilers, and different 
compilation flags, you can set three environmental variables 
to whatever you like: 

   OMPI_CPP, OMPI_CC, OMPI_CPPFLAGS, OMPI_CFLAGS and OMPI_LDFLAGS

The first two specify the system preprocessor and compiler you like 
to use and the last three ones the particular flags you want. 
Make sure you set their values *before* running ompicc.

The --ort options lets you select any runtime library you
might have built. For more information on this topic, please refer
to the doc/runtime.txt file.

Finally, based on OpenMP 4.0 OMPi supprts attached devices that
can execute offloaded code. Automatically configured devices are
shown with the --devinfo flag.