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/*
Copyright (C) 2013-2014 Marco Vassallo <gedeone-octave@users.sourceforge.net>
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 3 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "function.h"
/**
* Internal helper routine to evaluate the given function at a single
* point (as Array<double>). Returned is the function value also as
* Array<double>, which gets stored into the given array.
* too, so that they don't have to be constructed.
* @param f Dolfin function handle to evaluate.
* @param pt Point where we want to evaluate f as Octave array of coordinates.
* @param res Store the value here, should already be of the correct size.
*/
static void
evaluate (const dolfin::Function& f, const Array<double>& pt,
Array<double>& res)
{
Array<double>& ptNonconst = const_cast<Array<double>&> (pt);
dolfin::Array<double> x(ptNonconst.length (), ptNonconst.fortran_vec ());
dolfin::Array<double> values(res.length (), res.fortran_vec ());
f.eval (values, x);
}
DEFUN_DLD (feval, args, , "-*- texinfo -*-\n\
@deftypefn {Function File} {[@var{value}]} = \
feval (@var{function_name}, @var{Coordinate})\n\
@deftypefnx {Function File} {[@var{value}]} = \
feval (@var{function_name}, @var{x}, @var{y})\n\
@deftypefnx {Function File} {[@var{value}]} = \
feval (@var{function_name}, @var{x}, @var{y}, @var{z})\n\
Evaluate a function at a specific point of the domain and return the value. \n\
With only two arguments, @var{Coordinate} is assumed to be an array holding \n\
the coordinates of the point where the function should be evaluated. With \n\
three or more arguments, the coordinates are passed separately in @var{x}, \n\
@var{y} and optionally @var{z}. In the latter case and if the function \n\
returns scalar values, @var{x}, @var{y} and @var{z} may also be arrays to \n\
evaluate the function at multiple points at once.\n\
@seealso{Function}\n\
@end deftypefn")
{
int nargin = args.length ();
octave_value retval = 0;
if (nargin < 2)
print_usage ();
else
{
if (! function_type_loaded)
{
function::register_type ();
function_type_loaded = true;
mlock ();
}
if (args(0).type_id () == function::static_type_id ())
{
const function & fspo =
static_cast<const function&> (args(0).get_rep ());
const boost::shared_ptr<const dolfin::Function>
& f = fspo.get_pfun ();
dim_vector dims;
dims.resize (2);
dims(0) = 1;
dims(1) = f->value_dimension (0);
Array<double> res(dims);
if (nargin == 2)
{
Array<double> point = args(1).array_value ();
if (!error_state)
{
evaluate (*f, point, res);
retval = octave_value (res);
}
}
else
{
dim_vector inDims;
inDims.resize (2);
inDims(0) = 1;
inDims(1) = nargin - 1;
Array<double> point(inDims);
std::vector<Array<double> > coords;
coords.reserve (inDims(1));
dim_vector argDims;
for (unsigned i = 1; i < nargin; ++i)
{
coords.push_back (args(i).array_value ());
const dim_vector curDims = coords.back ().dims ();
if (i > 1 && argDims != curDims)
{
error ("feval: coordinate dimensions mismatch");
break;
}
argDims = curDims;
}
if (res.nelem () != 1)
error ("feval: separate coordinate version only supported"
"for scalar functions");
if (!error_state)
{
Array<double> retValArray(argDims);
for (size_t i = 0; i < retValArray.nelem (); ++i)
{
for (unsigned j = 0; j < coords.size (); ++j)
point(j) = coords[j].fortran_vec ()[i];
evaluate (*f, point, res);
retValArray.fortran_vec ()[i] = res(0);
}
retval = octave_value (retValArray);
}
}
}
}
return retval;
}

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