diff options
Diffstat (limited to 'libdimension/dimension')
| -rw-r--r-- | libdimension/dimension/geometry.h | 7 | ||||
| -rw-r--r-- | libdimension/dimension/polynomial.h | 51 |
2 files changed, 58 insertions, 0 deletions
diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h index 87e7ab7..4c4f8b8 100644 --- a/libdimension/dimension/geometry.h +++ b/libdimension/dimension/geometry.h @@ -96,6 +96,13 @@ dmnsn_degrees(double radians) return radians*45.0/atan(1.0); } +DMNSN_INLINE int +dmnsn_signbit(double n) +{ + /* Guarantee a 1 or 0 return, to allow testing two signs for equality */ + return signbit(n) ? 1 : 0; +} + /* Shorthand for vector/matrix construction */ DMNSN_INLINE dmnsn_vector diff --git a/libdimension/dimension/polynomial.h b/libdimension/dimension/polynomial.h new file mode 100644 index 0000000..52a44dd --- /dev/null +++ b/libdimension/dimension/polynomial.h @@ -0,0 +1,51 @@ +/************************************************************************* + * Copyright (C) 2009-2010 Tavian Barnes <tavianator@gmail.com> * + * * + * This file is part of The Dimension Library. * + * * + * The Dimension Library is free software; you can redistribute it and/ * + * or modify it under the terms of the GNU Lesser General Public License * + * as published by the Free Software Foundation; either version 3 of the * + * License, or (at your option) any later version. * + * * + * The Dimension Library 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 * + * Lesser General Public License for more details. * + * * + * You should have received a copy of the GNU Lesser General Public * + * License along with this program. If not, see * + * <http://www.gnu.org/licenses/>. * + *************************************************************************/ + +/* + * Utility functions for working with and numerically solving polynomials. + * Polynomials are represented as simple arrays where the ith element is the + * coefficient on x^i. In general, we are only interested in positive roots. + */ + +#ifndef DIMENSION_POLYNOMIAL_H +#define DIMENSION_POLYNOMIAL_H + +#include <stddef.h> +#include <stdio.h> + +DMNSN_INLINE double +dmnsn_evaluate_polynomial(double poly[], size_t degree, double x) +{ + double ret = poly[degree]; + ssize_t i; + for (i = degree - 1; i >= 0; --i) { + ret = ret*x + poly[i]; + } + return ret; +} + +/* Stores the non-negative roots of poly[] in x[], and returns the number of + such roots that were stored */ +size_t dmnsn_solve_polynomial(double poly[], size_t degree, double x[]); + +/* Helper function to print a polynomial */ +void dmnsn_print_polynomial(FILE *file, double poly[], size_t degree); + +#endif /* DIMENSION_POLYNOMIAL_H */ |