3. COMPLEX_FUNCTION Namelist

Analogous to the FUNCTION namelist, this namelist is used to define a complex-valued function that can be used in some situations where complex data is needed.

These are general complex-valued functions of one or more variables, \(f:\mathbb{R}^m\to\mathbb{C}\). The number of variables, and the unknowns they represent (e.g., time, position, etc.) depend on the context in which the function is used, and that is described by the documentation of those namelists where these functions can be used.

Currently the only type of function that is available is one from a shared object library having a simple Fortran or C-compatible interface. Written in Fortran the function interface must look like

subroutine myfun(v, p, r) bind(c)
complex(kind(1.0d0)), intent(in)  :: v(*), p(*)
complex(kind(1.0d0)), intent(out) :: r

where myfunc can, of course, be any name. The equivalent C interface is

#include <complex.h>
void myfun(double v[], double p[], double complex *r);

The vector of variables \(v= (v_1,...,v_m)\) is passed in the argument v and a vector of parameter values specified by parameters is passed in the argument p. The complex result is returned in the argument r. The path to the library is given by library_path and the name of the function (“myfun”, for example) is given by library_symbol. Note that the bind(c) attribute on the function declaration inhibits the Fortran compiler from mangling the function name (by appending an underscore, for example) as it normally would.

Note

Required/Optional:

Optional

Single/Multiple Instances:

Multiple

3.1. Namelist Variables

name

A unique name by which this vector function can be referenced by other namelists.

Type:

case-sensitive string (31 characters max)

Default:

none

type

The type of function defined by the namelist.

Type:

case-sensitive string

Default:

none

Valid values:

“library”

library_path

The path to the shared object library that contains the function.

Type:

A string of up to 128 characters.

Default:

none

library_symbol

The symbol name of the function within the shared object file.

Type:

A string of up to 128 characters.

Default:

none

Notes:

Unless the Fortran function is declared with the BIND(C) attribute, which is the recommended practice, a Fortran compiler will almost always mangle the name of the function so that the symbol name is not quite the same as the name in the source code. Use the UNIX/Linux command-line utility nm to list the symbol names in the library file to determine the correct name to use here.

parameters

Optional parameter values to pass to the shared library function.

Type:

real vector of up to 16 values

Default:

No parameters