Installing the Intel Fortran compiler

The Intel Fortran compiler works well with GEMPACK -- but Intel keeps modifying the compiler in ways that are not always compatible with current or past Releases of GEMPACK. The incompatibilities most often surface at GEMPACK install time. The GEMPACK developers constantly work to make the next annual GEMPACK release compatible with the latest Intel Fortran Version -- but there is a lag. Hence, you need to match your Intel Fortran version with your GEMPACK Release. To make things more interesting, the Intel marketing department has progressively devised its own system of naming successive versions of the Intel Fortran compiler, summarized below:

Intel Fortran
Version No.
Marketing Name
10.1 Intel Fortran 10.1
11.0 Intel Visual Fortran 11
11.1 Intel Visual Fortran 11.1
12 Intel Composer XE 2011 (released September 2010)
12.1 Intel Composer XE 2011 SP1 (released August 2011)
13 Intel Composer XE 2013 (released September 2012)
14 Intel Composer XE 2013 SP1 (released September 2013)
15 Intel Parallel Studio XE Composer Edition for Fortran Windows
(released August 2014)
16 Intel Parallel Studio XE 2016 Composer Edition for Fortran Windows
(released August 2015)
17 Intel Parallel Studio XE 2017 Composer Edition for Fortran Windows
(released September 2016)
18 Intel Parallel Studio XE 2018 Composer Edition for Fortran Windows
(released September 2017) NOT SUPPORTED BY GEMPACK

As of Feb 2018, non-GEMPACK users of Intel Fortran 18 reported various bugs; so we are not yet supporting it for GEMPACK use.

Below we refer to the version numbers in column 1 above. You need to use a Fortran version compatible with your GEMPACK Release, as summarized in the table below:

11.0 and 11.1
GEMPACK 10.0-000
(April 2008)
yes no no no no no no no
GEMPACK 10.0-001
(April 2009)
yes yes no no no no no no
(October 2011)
yes yes yes no no no no no
(May 2012)
yes yes yes no no no no no
(May 2013)
yes yes yes yes no no no no
(June 2014)
yes yes yes yes yes no no no
GEMPACK 11.3.004
(January 2015)
yes yes yes yes yes yes but no no
(January 2016)
no yes yes yes yes yes yes yes
(September 2018)
no no no yes yes yes yes yes

Download from Intel the latest version appropriate to your GEMPACK release. Intel allows customers with a current support services licence (usually lasting 1 year from date of purchase) to download previous Fortran versions. The procedure is described here.

Example: If you purchased both Source Code GEMPACK and Intel Fortran in March 2014, you would have paid for GEMPACK 11.2 and Intel Fortran Version 14. However, GEMPACK 11.2 only supports Intel Fortran Versions 10.1 to 13. Hence, you should download and install Intel Fortran Version 13. You may choose to also download (but not install) Intel Fortran Version 14, in case its new features are useful with some future version of GEMPACK.

Warning: Some users have reported (and we have confirmed) that Intel Fortran (15, 2015) both compiles and runs GEMPACK 11.3 programs considerably slower than previous versions. We suggest that GEMPACK 11.3 users download and use version 13 or 14, as described just above.

The oldest Intel Fortran supported by GEMPACK is Intel Fortran 10.1.021 (Build 20080312) [type "ifort" at command line to see your version/build numbers].

Later Intel Fortran versions compile and run rather faster than older versions. In addition, some include the Intel Math Kernel Library (MKL) which was previously an optional extra. The MKL is not needed or used by GEMPACK 11, but we may use the MKL (if you have it) in GEMPACK Release 12 to speed simulations.

Installation guides for Intel Fortran with GEMPACK

Potential 'missing DLL' problem

EXE files produced by GEMPACK 11.4 (or later) and the Intel compiler need to have access to a file called libiomp5md.dll. Normally access is guaranteed, since this file comes with both GEMPACK 11.4 and Intel Fortran. However, if you use GEMPACK 11.4 (or later) with Intel Fortran and intend to distribute TABLO-generated EXE files (for example, in RunDynam archives or in RunGTAP version zips) to other people who might not have installed Intel Fortran or GEMPACK 11.4, you should be aware of the missing DLL problem.

Windows 7

Issues have occasionally been reported with Intel Fortran and Windows 7, mentioned here. If using Windows 7, you may need to upgrade to Intel Fortran 11.1.048 or later.

Optimization bug in Intel Fortran 10.0 and early 10.1

32-bit Intel Fortran 10.0 (and early 10.1) has a bug in the optimizer, which conflicts with the faster-running compile options which are set by default when you install Release 10.0-001 (April 2009) or later Source-code GEMPACK. The bug was fixed for Intel Fortran 10.1.021 and later. If BOTH of the following conditions hold:

you may need to:

To check your version of Intel Fortran, type IFORT at the command prompt.

Working around the problem

The effect of the above is to re-compile your GEMPACK programs and libraries with less aggressive optimization settings that avoid the optimization bug. The downside is that your programs run a bit slower.

See also:

Fortran Compilers for Use with Source-Code GEMPACK