2 * \file interpolater.hxx
3 * Routines to handle linear interpolation from a table of x,y The
4 * table must be sorted by "x" in ascending order
7 // Written by Curtis Olson, started April 1998.
9 // Copyright (C) 1998 Curtis L. Olson - http://www.flightgear.org/~curt
11 // This library is free software; you can redistribute it and/or
12 // modify it under the terms of the GNU Library General Public
13 // License as published by the Free Software Foundation; either
14 // version 2 of the License, or (at your option) any later version.
16 // This library is distributed in the hope that it will be useful,
17 // but WITHOUT ANY WARRANTY; without even the implied warranty of
18 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 // Library General Public License for more details.
21 // You should have received a copy of the GNU General Public License
22 // along with this program; if not, write to the Free Software
23 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
28 #ifndef _INTERPOLATER_H
29 #define _INTERPOLATER_H
33 # error This library requires C++
36 #include <simgear/compiler.h>
46 * A class that provids a simple linear 2d interpolation lookup table.
47 * The actual table is expected to be loaded from a file. The
48 * independant variable must be strictly ascending. The dependent
49 * variable can be anything.
56 : ind(0.0L), dep(0.0L) {}
57 Entry (double independent, double dependent)
58 : ind(independent), dep(dependent) {}
69 * Constructor. Creates a new, empty table.
74 * Constructor. Loads the interpolation table from the specified file.
75 * @param file name of interpolation file
77 SGInterpTable( const string& file );
81 * Add an entry to the table, extending the table's length.
83 * @param ind The independent variable.
84 * @param dep The dependent variable.
86 void addEntry (double ind, double dep);
90 * Given an x value, linearly interpolate the y value from the table.
91 * @param x independent variable
92 * @return interpolated dependent variable
94 double interpolate(double x) const;
101 #endif // _INTERPOLATER_H