Changeset 42319 for branches/eam_branches/psLib.20230123/src/math/psSpline.h

Timestamp:

Jan 23, 2023, 7:10:15 AM (3 years ago)

Author:

eugene

Message:

workin on spline implementation

File:

• branches/eam_branches/psLib.20230123/src/math/psSpline.h (modified) (4 diffs)

branches/eam_branches/psLib.20230123/src/math/psSpline.h

@@ -5 +5 @@
  * and evaluate splines.
  *
- * @author GLG, MHPCC
+ * @author GLG (MHPCC)
+ * reworked by EAM (IfA)
  *
  * @version $Revision: 1.62 $ $Name: not supported by cvs2svn $
@@ -27 +28 @@
 #include "psPolynomial.h"
 
-#define PS_LEFT_SPLINE_DERIV 0.0
-#define PS_RIGHT_SPLINE_DERIV 0.0
-
-/** One-Dimensional Spline */
+/** One-Dimensional Spline
+    This structure represents a 1D cubic spline.  Note the option for 
+    equally-spaced knots allows a quick selection of the correct spline 
+    segment.  The values (xMin, xMax, xDel) are stored for ease of access.
+ */
 typedef struct
 {
     unsigned int n;                    ///< The number of spline pieces
-    psPolynomial1D **spline;           ///< An array of n pointers to the spline polynomials
-    psVector *knots;                   ///< The boundaries between each spline piece.  Size is n+1.
-    psF32 *p_psDeriv2;                 ///< For cubic splines, the second derivative at each domain point.  Size is n+1.
+    psF32 *xKnots; ///< x-coordinate of the knots (n+1)
+    psF32 *yKnots; ///< y-coordinate of the knots (n+1)
+    psF32 *d2yKnots; ///< 2nd derivative of y at the knots (n+1)
+    bool equalSpacing; // if knots are equally spaced, the seqment choice can be optimized
+    psF32 xMin; // for equally-spaced knots, the value at the lower bound (xKnots[0])
+    psF32 xMax; // for equally-spaced knots, the value at the upper bound (xKnots[n])
+    psF32 xDel; // for equally-spaced knots, the spacing (xKnots[n] - xKnots[0])/n
 }
 psSpline1D;
 
-/** Allocates a psSpline1D structure
- *
- *  Allocator for psSpline1D.
+/** Allocator for psSpline1D.
  *
  *  @return psSpline1D*    new 1-D spline struct
@@ -53 +57 @@
  */
 float psSpline1DEval(
-    const psSpline1D *spline,          ///< Coefficients for spline polynomials
+    const psSpline1D *spline,          ///< spline pointer
     float x                            ///< location at which to evaluate
 );
@@ -71 +75 @@
  *  generates the linear splines which satisfy those data points.
  *
+ *  XXX EAM: add option to generate / select a subset of knots from the data
+ *
  *  @return psSpline1D*:  the calculated one-dimensional splines
  */
-psSpline1D *psVectorFitSpline1D(
+psSpline1D *psSpline1DFitVector(
     const psVector* x,                 ///< Ordinates (or NULL to just use the indices)
     const psVector* y                  ///< Coordinates