interp_fit.h

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/* +---------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)               |
   |                          http://www.mrpt.org/                             |
   |                                                                           |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file        |
   | See: http://www.mrpt.org/Authors - All rights reserved.                   |
   | Released under BSD License. See details in http://www.mrpt.org/License    |
   +---------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/utils/utils_defs.h>
#include <mrpt/math/CMatrixTemplateNumeric.h>
#include <mrpt/math/wrap2pi.h>

namespace mrpt 
{
        namespace math
        {
                /** @addtogroup interpolation_grp Interpolation, least-squares fit, splines
                  * \ingroup mrpt_base_grp
                  *  @{ */

                /** Interpolate a data sequence "ys" ranging from "x0" to "x1" (equally spaced), to obtain the approximation of the sequence at the point "x".
                  *  If the point "x" is out of the range [x0,x1], the closest extreme "ys" value is returned. 
                  * \note Implementation in `#include <mrpt/math/interp_fit.hpp>`
                  * \sa spline, interpolate2points
                  */
                template <class T,class VECTOR>
                T interpolate(const T &x, const VECTOR &ys, const T &x0, const T &x1);

                /** Linear interpolation/extrapolation: evaluates at "x" the line (x0,y0)-(x1,y1).
                  *  If wrap2pi is true, output is wrapped to ]-pi,pi] (It is assumed that input "y" values already are in the correct range).
                  * \sa spline, interpolate, leastSquareLinearFit
                  */
                double BASE_IMPEXP interpolate2points(const double x, const double x0, const double y0, const double x1, const double y1, bool wrap2pi = false);

                /** Interpolates the value of a function in a point "t" given 4 SORTED points where "t" is between the two middle points
                  *  If wrap2pi is true, output "y" values are wrapped to ]-pi,pi] (It is assumed that input "y" values already are in the correct range).
                  * \sa leastSquareLinearFit
                  * \note Implementation in `#include <mrpt/math/interp_fit.hpp>`
                  */
                template <typename NUMTYPE, class VECTORLIKE>
                NUMTYPE spline(const NUMTYPE t, const VECTORLIKE &x, const VECTORLIKE &y, bool wrap2pi = false);

                /** Interpolates or extrapolates using a least-square linear fit of the set of values "x" and "y", evaluated at a single point "t".
                  *  The vectors x and y must have size >=2, and all values of "x" must be different.
                  *  If wrap2pi is true, output "y" values are wrapped to ]-pi,pi] (It is assumed that input "y" values already are in the correct range).
                  * \sa spline
                  * \sa getRegressionLine, getRegressionPlane
                  * \note Implementation in `#include <mrpt/math/interp_fit.hpp>`
                  */
                template <typename NUMTYPE,class VECTORLIKE, int NUM_POINTS = Eigen::Dynamic>
                NUMTYPE leastSquareLinearFit(const NUMTYPE t, const VECTORLIKE &x, const VECTORLIKE &y, bool wrap2pi = false);

                /** Interpolates or extrapolates using a least-square linear fit of the set of values "x" and "y", evaluated at a sequence of points "ts" and returned at "outs".
                  *  If wrap2pi is true, output "y" values are wrapped to ]-pi,pi] (It is assumed that input "y" values already are in the correct range).
                  * \sa spline, getRegressionLine, getRegressionPlane
                  * \note Implementation in `#include <mrpt/math/interp_fit.hpp>`
                  */
                template <class VECTORLIKE1,class VECTORLIKE2,class VECTORLIKE3, int NUM_POINTS = Eigen::Dynamic>
                void leastSquareLinearFit(const VECTORLIKE1 &ts,VECTORLIKE2 &outs,const VECTORLIKE3 &x,const VECTORLIKE3 &y,bool wrap2pi = false);

                /** @} */  // end grouping interpolation_grp

} // End of MATH namespace
} // End of namespace