A..3.2 Prerequisites

The following are required or strongly recommended for installation from source code.

1. A Fortran 90 compiler. Fortran77-only compilers will not suffice. On most systems, the latest vendor-supplied compiler should be used. On Intel Linux, the Portland pgf90 compiler, version 3.2 or higher, is recommended. For using this compiler it is required that the environment variable PGI is set and points to the root directory where the compiler is installed, e.g., /usr/local/pgi. MOLPRO has also been tested with the Intel Compiler ifc, Version 5.0.1. In order to use this compiler the environment variable IA32ROOT must be set, and point to the appropriate directory, normally
   /opt/intel/compiler50/ia32. On Alpha Linux, the Compaq compiler is recommended. The directory in which the compiler is located must be in your PATH.

2. GNU make, freely available from http://www.fsf.org and mirrors. GNU make must be used; most system-standard makes do not work. In order to avoid the use of a wrong make, and to suppress extensive output of GNU make, it may be useful to set an alias, e.g., alias make='gmake -s'.

3. The GNU wget utility for batch-mode http transfers, although not needed for installation, is essential for any subsequent application of patches that implement bug fixes.

4. About 200Mb disk space (strongly system-dependent; more with large-blocksize file systems, and where binary files are large) during compilation. Typically 30Mb is needed for the finally installed program.

5. One or more large scratch file systems, each containing a directory that users may write on. There are parts of the program in which demanding I/O is performed simultaneously on two different files, and it is therefore helpful to provide at least two filesystems on different physical disks if other solutions, such as striping, are not available. The directory names should be stored in the environment variables $TMPDIR, $TMPDIR2, $TMPDIR3,$\dots$. These variables should be set before the program is installed (preferably in .profile or .cshrc), since at some stages the installation procedures will check for them (cf. section 3.6).

6. If the program is to be built for parallel execution, the Global Arrays toolkit, version 3.1 or later is needed. This is available from http://www.emsl.pnl.gov:2080/docs/global/ga.html, and should be installed prior to compiling MOLPRO. In some installations, GA uses the tcgmsg parallel harness; on others, it sits on an existing MPI subsystem, and on others, it makes use of the native parallel subsystem (e.g., LAPI). MOLPRO can be built to use any of these, although it is not normally recommended to use MPI where other possibilities exist. For more information, see section 3.3.

7. The source distribution of MOLPRO, which consists of a base compressed tar archive with a file name of the form molpro.2002.7 .tar.gz, together, possibly, with one or more module archives with file names of the form molpro.module.2002.7 .tar.gz. The modules contain code which is not generally distributed, or features which are not always required to install the code. An example of the former is the program developers' kit (module=develop); an example of the latter is the documentation (module=doc). The archives can be unpacked using gunzip and tar. All archives must be unpacked in the same directory. It is essential that the base archive is unpacked first, and advisable that any modules are unpacked before further installation.

   Under some circumstances, MOLPRO is delivered as a single tar file with a name of the form molpro.all.2002.7 .tar. This archive contains all necessary base and module compressed tar archives, together with a shell script unpack which performs the unpacking described above.