This is release 0.9.4 of the Fortran interface 
to the GNU Scientific Library. It is based on version 1.15 of GSL, 
but should also work with later releases apart from missing API
mappings.

Please consult the NEWS file for a change log.

While this release supports a large subset of 
GSL functionality, there are a number of things missing still:

* for the most part, no generics yet for varying types and kinds
* 1d and 2d vector/matrix API is not explicitly supported, but mapping
  routines to Fortran arrays and pointers are available
* no support yet for non-interoperable function and polymorphic
  arguments. This will be done once the compilers are ready.
* the test suite is still incomplete


License:
~~~~~~~~

FGSL is released under Version 2 or later of the GPL.

Installation procedure:
~~~~~~~~~~~~~~~~~~~~~~~

(A) prerequisites:

 1. An installation of GSL libraries and include files 
 2. The ANSI C compiler used to build the GSL installation
 3. A Fortran 95 compiler which additionally implements the
    following Fortran 2003 features:
    - the IMPORT statement
    - Interoperability with C (more specifically, the C processor
      mentioned in 2. above). The intrinsic ISO_C_BINDING
      module and all of its functionality except C_F_PROCPOINTER
      is needed. The configure script checks the needed subset
      of interoperable intrinsic types.
    - INTENT for pointers.


Note that to date, the following compilers have been verified to 
correctly build the library and run the test programs:

    - g95 0.92. On 64 bit systems, please use a version
      from after August 14, 2008, earlier releases have problems
      with C interoperable functions returning structures.
    - NAG 5.1 build 344 or higher (32 bit). Please perform 
export GSL_IEEE_MODE="mask-invalid,mask-underflow,mask-denormalized" 
      before running the test program, or build with the option
      -ieee=full (this was not checked with the 0.9 release).
    - NAG 5.2 on 32 and 64 bit systems.
    - Intel Fortran 11.1 U5 and later

In particular, the following compilers FAIL to build and/or run FGSL:

    - IBM xlf 10.1.0.5 and lower fails to build the library due to 
      non-implemented character length to array mapping.
      10.1.0.6 builds the library, but fails to build any application
      using the module due to spurious label duplication errors.
    - NAG 5.1 on 64 bit. There is no support for a c_size_t shape array
      constructor for c_f_pointer.
    - Sun Studio 12U1 lacks support for POINTER intent, and has an 
      additional bug which still needs to be tracked down.
    - Intel ifort versions 10.1, 11.0 and 11.1 up to (I think) U4 
      had a problem with C interoperable functions returning 
      structures on 64 bit systems. 
      As a consequence, the tests poly.exe and array.exe will crash
      with a segmentation fault when using these compilers.
    - PGI 10.x (x up to 4) has sufficient C interop support to build
      FGSL, but has the same issue on 64 bit systems as described above
      for the Intel compiler.
    - Pathscale 3.2 has too buggy C interop support to build FGSL.
    - gfortran 4.3.x does not support complex(c_double).
    - gfortran 4.4.1 builds OK, but fails the last montecarlo test, 
      apparently due to a spurious c_associated() call.
    - IBM xlf 11.1 and higher builds the library and the tests.
      Some tests fail, apparently due to being miscompiled (illegal
      instruction). This requires further investigation.

(B) build procedure:

export FFLAGS=<additional Fortran flags>
./configure [--prefix <inst_path>] [--gsl <gsl_inst_path>] \
            [--f90 <f90_compiler] [--bits <32|64>] [--debug] 
make
    Builds the module information file and a static library.
    Testing can be performed by doing
make test
    which should produce a number of lines reading 
    "OK: All tests passed".
    For a debug version of the library using a debug build of GSL
    is recommended. Furthermore, if the GSL installation contains 
    shared libraries, you may need add an entry to LD_LIBRARY_PATH
    pointing to the lib subdirectory of the GSL installation before
    running the tests.

make install
    this installs the library as well as the documentation into 
    suitable subdirectories of $GSL_INST_PATH or, if specified, 
    the prefix part. 

(C) usage:

With F90 denoting the Fortran compiler and GSL_INST_PATH the GSL installation
path, and assuming GSL_INST_PATH was also chosen as installation prefix for
FGSL:

$F90 -o myprog.exe -I$GSL_INST_PATH/include/$F90 myprog.f90 \
     -L$GSL_INST_PATH/lib -lfgsl_${F90} -lgsl -lgslcblas


Reporting Bugs etc.
~~~~~~~~~~~~~~~~~~~

Patches and/or bug reports are very welcome and should be directed
to Bader_at_lrz_dot_de

Suggestions for implementations of missing bits will be worked
on by me as time allows. 

Releases:

  * 0.5: End of March, 2007 (revision 1636)
  * 0.6: End of April, 2007 (revision 1680)
  * 0.7: End of July, 2007 (revision 1809)
  * 0.8: Early October, 2007 (revision 1940)
  * 0.8.1: Early April, 2008 (revision 2282) 
  * 0.9: End of August, 2008 (revision 2578)
  * 0.9.1 Early September, 2009 (revision 3355)
  * 0.9.2 September 22, 2009 (revision 3380)
  * 0.9.3 May 01, 2010 (revision 4123)
  * 0.9.4 May 31, 2011 (revision 5233)
  * 1.0: ???