[Toon-members] TooN irls.h

[Edward Rosten]

CVSROOT:        /cvsroot/toon
Module name:    TooN
Changes by:     Edward Rosten <edrosten>        09/07/16 14:10:09

Modified files:
        .              : irls.h 

Log message:
        Added RobustIII 

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/TooN/irls.h?cvsroot=toon&r1=1.9&r2=1.10

Patches:
Index: irls.h
===================================================================
RCS file: /cvsroot/toon/TooN/irls.h,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -b -r1.9 -r1.10
--- irls.h      21 May 2009 20:04:24 -0000      1.9
+++ irls.h      16 Jul 2009 14:10:07 -0000      1.10
@@ -43,6 +43,7 @@
        /// @ingroup gEquations
        template<typename Precision>
        struct RobustI {
+               void set_sd(Precision x){ sd_inlier = x;} ///<Set the noise 
standard deviation.
                double sd_inlier; ///< The inlier standard deviation, 
\f$\sigma\f$.
                inline Precision reweight(Precision x) {return 
1/(sd_inlier+fabs(x));}  ///< Returns \f$w(x)\f$.
                inline Precision true_scale(Precision x) {return reweight(x) - 
fabs(x)*reweight(x)*reweight(x);}  ///< Returns \f$w(x) + xw'(x)\f$.
@@ -55,7 +56,8 @@
        /// @ingroup gEquations
        template<typename Precision>
        struct RobustII {
-               Precision sd_inlier; ///< The inlier standard deviation, 
\f$\sigma\f$.
+               void set_sd(Precision x){ sd_inlier = x*x;} ///<Set the noise 
standard deviation.
+               Precision sd_inlier; ///< The inlier standard deviation 
squared, \f$\sigma\f$.
                inline Precision reweight(Precision d){return 
1/(sd_inlier+d*d);} ///< Returns \f$w(x)\f$.
                inline Precision true_scale(Precision d){return d - 
2*d*reweight(d);} ///< Returns \f$w(x) + xw'(x)\f$.
                inline Precision objective(Precision d){return 0.5 * log(1 + 
d*d/sd_inlier);} ///< Returns \f$\int xw(x)dx\f$.
@@ -67,11 +69,34 @@
        /// @ingroup gEquations
        template<typename Precision>
        struct ILinear {
+               void set_sd(Precision){} ///<Set the noise standard deviation 
(does nothing).
                inline Precision reweight(Precision d){return 1;} ///< Returns 
\f$w(x)\f$.
                inline Precision true_scale(Precision d){return 1;} ///< 
Returns \f$w(x) + xw'(x)\f$.
                inline Precision objective(Precision d){return d*d;} ///< 
Returns \f$\int xw(x)dx\f$.
        };
 
+       ///A reweighting class where the objective function tends to a 
+       ///fixed value, rather than infinity. Note that this is not therefore
+       ///a proper distribution since its integral is not finite. It is 
considerably
+       ///more efficient than RobustI and II, since log() is not used.
+       /// @ingroup gEquations
+       template<typename Precision>
+       struct RobustIII {
+
+               void set_sd(Precision x){ sd_inlier = x*x;} ///<Set the noise 
standard deviation.
+               T sd_inlier; ///< Inlier standard deviation squared.
+               /// Returns \f$w(x)\f$.
+               T reweight(T x) const
+               {
+                       double d = (1 + x*x/sd_inlier);
+                       return 1/(d*d);
+               }       
+               ///< Returns \f$\int xw(x)dx\f$.
+               T objective(T x) const 
+               {
+                       return x*x / (2*(1 + x*x/sd_inlier));
+               }
+       };
 
        /// Performs iterative reweighted least squares.
        /// @param Size the size