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Diffstat (limited to 'Utilib/src/zeroin.h')
| -rw-r--r-- | Utilib/src/zeroin.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/Utilib/src/zeroin.h b/Utilib/src/zeroin.h new file mode 100644 index 0000000..bcd43fe --- /dev/null +++ b/Utilib/src/zeroin.h @@ -0,0 +1,65 @@ +/* +freesteam - IAPWS-IF97 steam tables library +Copyright (C) 2004-2009 John Pye + +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 2 +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, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +*/ + +#ifndef FREESTEAM_ZEROIN_H +#define FREESTEAM_ZEROIN_H + +#include "common.h" + +/** + Any function that you want to solve using the 'zeroin_solve' function + needs to conform to this function prototype. Any parameters required + internally by the function can be passed in to the function as a pointer + to a struct, array, etc, via the void 'user_data' pointer. Your subject + function can then cast the pointer to its correct type, and access the + necesssary parameter data, for example: + + -- in your main code + typedef struct{double param1, param2} MyData; + MyData D = {100., 3.141}; + double myfunc(double x, void *user_data){ + MyData *D1 = (MyData *)user_data; + return x * D1->param1 + D1->param2; + } + zeroin_solve(&myfunc, &D, ...); +*/ +typedef double ZeroInSubjectFunction(double, void *user_data); + +/** + Attempt to solve the function y = f(x) = 0 by varying x between + a lower and upper bound, using the Brent algorithm. + + Originally based on brent solver from netlib, then converted to C++ for + used in earlier freesteam versions, and now converted back to pure C again. + @see brent.shar at http://www.netlib.org/c/ + + @param func the function being solved, must be a ZeroInSubjectFunction. + @param lowerbound the lower bound of the range in which a root is sought + @param upperbound the upper bound of the range in which a root is sought + @param tol maximum permissible magnitude of the function at the solved root location + @param user_data additional data that will be passed to the subject function func. + @param solution (returned) the value of 'x' at the solution + @param error (returned) the value of 'y' at the solution. + @return 0 on success +*/ + +FREESTEAM_DLL char zeroin_solve(ZeroInSubjectFunction *func, void *user_data, double lowerbound, double upperbound, double tol, double *solution, double *error); + +#endif + |