uk.ac.diamond.scisoft.analysis.dataset.function.Interpolation2D.java Source code

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Here is the source code for uk.ac.diamond.scisoft.analysis.dataset.function.Interpolation2D.java

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/*-
 * Copyright 2016 Diamond Light Source Ltd.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package uk.ac.diamond.scisoft.analysis.dataset.function;

import org.apache.commons.math3.analysis.BivariateFunction;
import org.apache.commons.math3.analysis.interpolation.BicubicInterpolator;
import org.apache.commons.math3.analysis.interpolation.BivariateGridInterpolator;
import org.apache.commons.math3.analysis.interpolation.PiecewiseBicubicSplineInterpolator;
import org.apache.commons.math3.exception.NonMonotonicSequenceException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.exception.OutOfRangeException;
import org.eclipse.dawnsci.analysis.api.dataset.IDataset;
import org.eclipse.dawnsci.analysis.dataset.impl.Dataset;
import org.eclipse.dawnsci.analysis.dataset.impl.DatasetFactory;
import org.eclipse.dawnsci.analysis.dataset.impl.DatasetUtils;
import org.eclipse.dawnsci.analysis.dataset.impl.DoubleDataset;

public class Interpolation2D {

    public static Dataset bicubicInterpolation(IDataset oldx, IDataset oldy, IDataset oldxy, IDataset newx,
            IDataset newy) {

        return interpolate(oldx, oldy, oldxy, newx, newy, new BicubicInterpolator());

    }

    public static Dataset piecewiseBicubicSplineInterpolation(IDataset oldx, IDataset oldy, IDataset oldxy,
            IDataset newx, IDataset newy) {

        return interpolate(oldx, oldy, oldxy, newx, newy, new PiecewiseBicubicSplineInterpolator());

    }

    public static Dataset interpolate(IDataset oldx, IDataset oldy, IDataset oldxy, IDataset newx, IDataset newy,
            BivariateGridInterpolator interpolator)
            throws NonMonotonicSequenceException, NumberIsTooSmallException {

        //check shapes
        if (oldx.getRank() != 1)
            throw new IllegalArgumentException("oldx Shape must be 1D");
        if (oldy.getRank() != 1)
            throw new IllegalArgumentException("oldy Shape must be 1D");
        if (oldxy.getRank() != 2)
            throw new IllegalArgumentException("oldxy Shape must be 2D");
        if (oldx.getShape()[0] != oldxy.getShape()[0])
            throw new IllegalArgumentException("oldx Shape must match oldxy Shape[0]");
        if (oldy.getShape()[0] != oldxy.getShape()[1])
            throw new IllegalArgumentException("oldy Shape must match oldxy Shape[1]");
        if (newx.getRank() != 1)
            throw new IllegalArgumentException("newx Shape must be 1D");
        if (newy.getRank() != 1)
            throw new IllegalArgumentException("newx Shape must be 1D");
        if (newy.getSize() != newx.getSize())
            throw new IllegalArgumentException("newx and newy Size must be identical");

        DoubleDataset oldx_dd = (DoubleDataset) DatasetUtils.cast(oldx, Dataset.FLOAT64);
        DoubleDataset oldy_dd = (DoubleDataset) DatasetUtils.cast(oldy, Dataset.FLOAT64);
        DoubleDataset oldxy_dd = (DoubleDataset) DatasetUtils.cast(oldxy, Dataset.FLOAT64);

        //unlike in Interpolation1D, we will not be sorting here, as it just too complicated
        //the user will be responsible for ensuring the arrays are properly sorted

        //oldxy_dd needs to be transformed into a double[][] array
        //this call may throw an exception that needs handling by the calling method
        BivariateFunction func = interpolator.interpolate(oldx_dd.getData(), oldy_dd.getData(),
                convertDoubleDataset2DtoPrimitive(oldxy_dd));

        Dataset rv = DatasetFactory.zeros(new int[] { newx.getSize() }, Dataset.FLOAT64);
        rv.setName(oldxy.getName() + "_interpolated");

        for (int i = 0; i < newx.getSize(); i++) {
            double val = 0.0;
            try {
                val = func.value(newx.getDouble(i), newy.getDouble(i));
                rv.set(val, i);
            } catch (OutOfRangeException e) {
                rv.set(0.0, i);
            }
        }

        return rv;
    }

    private static double[][] convertDoubleDataset2DtoPrimitive(DoubleDataset dataset) {
        if (dataset.getRank() != 2)
            throw new IllegalArgumentException("dataset Shape must be 2D");

        double[][] rv = new double[dataset.getShape()[0]][dataset.getShape()[1]];

        for (int row = 0; row < dataset.getShape()[0]; row++) {
            System.arraycopy(dataset.getData(), row * dataset.getShape()[1], rv[row], 0, dataset.getShape()[1]);
        }

        return rv;
    }
}