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authorTavian Barnes <tavianator@gmail.com>2010-11-01 15:44:31 -0400
committerTavian Barnes <tavianator@gmail.com>2010-11-01 15:44:31 -0400
commit9660ace0d566aea48656678dcc26d2af60f3bf49 (patch)
tree1fc12e3456f7ed6190894c4659e0c5d399e73300
parent5226e19e3bf2e082b02dec9e856e2613744c8571 (diff)
downloaddimension-9660ace0d566aea48656678dcc26d2af60f3bf49.tar.xz
Slight polynomial base case optimizations.
-rw-r--r--libdimension/polynomial.c49
1 files changed, 25 insertions, 24 deletions
diff --git a/libdimension/polynomial.c b/libdimension/polynomial.c
index ab80f69..c960c6f 100644
--- a/libdimension/polynomial.c
+++ b/libdimension/polynomial.c
@@ -21,29 +21,6 @@
#include "dimension.h"
#include <math.h>
-/* Basic solving methods */
-
-static inline size_t
-dmnsn_solve_linear(const double poly[2], double x[1])
-{
- x[0] = -poly[0]/poly[1];
- return (x[0] >= dmnsn_epsilon) ? 1 : 0;
-}
-
-static inline size_t
-dmnsn_solve_quadratic(const double poly[3], double x[2])
-{
- double disc = poly[1]*poly[1] - 4.0*poly[0]*poly[2];
- if (disc >= 0.0) {
- double s = sqrt(disc);
- x[0] = (-poly[1] + s)/(2.0*poly[2]);
- x[1] = (-poly[1] - s)/(2.0*poly[2]);
- return (x[0] >= dmnsn_epsilon) ? ((x[1] >= dmnsn_epsilon) ? 2 : 1) : 0;
- } else {
- return 0;
- }
-}
-
/* Get the real degree of a polynomial, ignoring leading zeros */
static inline size_t
dmnsn_real_degree(const double poly[], size_t degree)
@@ -61,9 +38,10 @@ dmnsn_real_degree(const double poly[], size_t degree)
static inline void
dmnsn_normalize_polynomial(double poly[], size_t degree)
{
- for (size_t i = 0; i <= degree; ++i) {
+ for (size_t i = 0; i < degree; ++i) {
poly[i] /= poly[degree];
}
+ poly[degree] = 1.0;
}
/* Eliminate trivial zero roots from poly[] */
@@ -279,6 +257,29 @@ dmnsn_eliminate_root(double poly[], size_t *degree, double r)
--*degree;
}
+/* Basic solving methods -- assuming normalized polynomial */
+
+static inline size_t
+dmnsn_solve_linear(const double poly[2], double x[1])
+{
+ x[0] = -poly[0];
+ return (x[0] >= dmnsn_epsilon) ? 1 : 0;
+}
+
+static inline size_t
+dmnsn_solve_quadratic(const double poly[3], double x[2])
+{
+ double disc = poly[1]*poly[1] - 4.0*poly[0];
+ if (disc >= 0.0) {
+ double s = sqrt(disc);
+ x[0] = (-poly[1] + s)/2.0;
+ x[1] = (-poly[1] - s)/2.0;
+ return (x[0] >= dmnsn_epsilon) ? ((x[1] >= dmnsn_epsilon) ? 2 : 1) : 0;
+ } else {
+ return 0;
+ }
+}
+
/* Uspensky's algorithm */
size_t
dmnsn_solve_polynomial(const double poly[], size_t degree, double x[])