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diff --git a/libdimension/dimension/math.h b/libdimension/dimension/math.h
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+/*************************************************************************
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.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/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Useful math functions.
+ */
+
+#include <math.h>
+#include <stdbool.h>
+
+/** The smallest value considered non-zero by some numerical algorithms. */
+#define dmnsn_epsilon 1.0e-10
+
+/**
+ * @def DMNSN_INFINITY
+ * Expands to floating-point infinity.
+ */
+#if defined(INFINITY) || DMNSN_C99
+  #define DMNSN_INFINITY INFINITY
+#else
+  #define DMNSN_INFINITY HUGE_VAL
+#endif
+
+/** Find the minimum of two values. */
+DMNSN_INLINE double
+dmnsn_min(double a, double b)
+{
+  return a < b ? a : b;
+}
+
+/** Find the maximum of two values. */
+DMNSN_INLINE double
+dmnsn_max(double a, double b)
+{
+  return a > b ? a : b;
+}
+
+/** Clamp a value to an interval. */
+DMNSN_INLINE double
+dmnsn_clamp(double n, double min, double max)
+{
+  return dmnsn_min(dmnsn_max(n, min), max);
+}
+
+/** Convert degrees to radians. */
+DMNSN_INLINE double
+dmnsn_radians(double degrees)
+{
+  return degrees*(atan(1.0)/45.0);
+}
+
+/** Convert radians to degrees. */
+DMNSN_INLINE double
+dmnsn_degrees(double radians)
+{
+  return radians*(45.0/atan(1.0));
+}
+
+/** Signum function: return the sign of a value. */
+DMNSN_INLINE int
+dmnsn_sgn(double n)
+{
+  if (n > 0.0) {
+    return 1;
+  } else if (n < 0.0) {
+    return -1;
+  } else {
+    return 0;
+  }
+}
+
+/** Return whether a value is NaN. */
+DMNSN_INLINE bool
+dmnsn_isnan(double n)
+{
+#if DMNSN_C99
+  return isnan(n);
+#else
+  return n != n;
+#endif
+}