/**
* Copyright (C) 2013 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.analytics.math.interpolation;
import java.util.ArrayList;
import com.opengamma.analytics.math.matrix.DoubleMatrix1D;
import com.opengamma.analytics.math.matrix.DoubleMatrix2D;
/**
* Result of 2D interpolation by piecewise polynomial f(x0,x1) containing
* _knots0: Positions of knots in x0 direction
* _knots1: Positions of knots in x1 direction
* _coefMatrix: Coefficient matrix whose (i,j) element is a DoubleMatrix2D containing coefficients for the square, _knots0_i < x0 < _knots0_{i+1}, _knots1_j < x1 < _knots1_{j+1},
* Each DoubleMatrix2D is c_ij where f(x0,x1) = sum_{i=0}^{order0-1} sum_{j=0}^{order1-1} coefMat_{ij} (x0-knots0_i)^{order0-1-i} (x1-knots1_j)^{order0-1-j}
* _nIntervals: Number of intervals in x0 direction and x1 direction, respectively, which should be (Number of knots) - 1
* _order: Number of coefficients in polynomial in terms of x0 and x1, respectively, which is equal to (polynomial degree) + 1
*/
public class PiecewisePolynomialResult2D {
private final DoubleMatrix1D _knots0;
private final DoubleMatrix1D _knots1;
private final DoubleMatrix2D[][] _coefMatrix;
private final int[] _nIntervals;
private final int[] _order;
/**
* @param knots0 The knots in the x0 direction
* @param knots1 The knots in the x1 direction
* @param coefMatrix The coefficient matrix
* @param order The order of the polynomial
*/
public PiecewisePolynomialResult2D(final DoubleMatrix1D knots0, final DoubleMatrix1D knots1, final DoubleMatrix2D[][] coefMatrix, final int[] order) {
_knots0 = knots0;
_knots1 = knots1;
_coefMatrix = coefMatrix;
_nIntervals = new int[2];
_nIntervals[0] = knots0.getNumberOfElements() - 1;
_nIntervals[1] = knots1.getNumberOfElements() - 1;
_order = order;
}
/**
* Access _knots0 and _knots1
* @return _knots0 and _knots1 contained in a ArrayList
*/
public ArrayList<DoubleMatrix1D> getKnots2D() {
final ArrayList<DoubleMatrix1D> res = new ArrayList<>();
res.add(_knots0);
res.add(_knots1);
return res;
}
/**
* Access _knots0
* @return _knots0
*/
public DoubleMatrix1D getKnots0() {
return _knots0;
}
/**
* Access _knots1
* @return knots1
*/
public DoubleMatrix1D getKnots1() {
return _knots1;
}
/**
* Access _coefMatrix
* @return _coefMatrix
*/
public DoubleMatrix2D[][] getCoefs() {
return _coefMatrix;
}
/**
* Access _nIntervals
* @return _nIntervals
*/
public int[] getNumberOfIntervals() {
return _nIntervals;
}
/**
* Access _order
* @return _order
*/
public int[] getOrder() {
return _order;
}
}