Oracle.java

/*-
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 * Copyright (C) 2020 Johan Vos
 * %%
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 * 1. Redistributions of source code must retain the above copyright notice, this
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 *    may be used to endorse or promote products derived from this software without
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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package org.redfx.strange.gate;


import org.redfx.strange.Complex;
import org.redfx.strange.Gate;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;


/**
 * <p>Oracle class.</p>
 *
 * @author alain
 * @version $Id: $Id
 */
public class Oracle implements Gate {

    private int mainQubit = 0;
    private List<Integer> affected = new LinkedList<>();
    private Complex[][] matrix;
    private String caption = "Oracle";
    private int span = 1;

    /**
     * <p>Constructor for Oracle.</p>
     *
     * @param i a int
     */
    public Oracle (int i) {
        this.mainQubit = i;
    }
    /**
     * <p>Constructor for Oracle.</p>
     *
     * @param matrix an array of {@link org.redfx.strange.Complex} objects
     */
    public Oracle(Complex[][] matrix) {
        this.matrix = matrix;
        sanitizeMatrix();
        span = (int)(Math.log(matrix.length)/Math.log(2));
        for (int i = 0; i < span;i++) {
            setAdditionalQubit(i,i);
        }
    }
 
    /** {@inheritDoc} */
    @Override
    public int getSize() {
        return span;
    }
    
    /**
     * <p>Setter for the field <code>caption</code>.</p>
     *
     * @param c a {@link java.lang.String} object
     */
    public void setCaption(String c) {
        this.caption = c;
    }

    /** {@inheritDoc} */
    @Override
    public void setMainQubitIndex(int idx) {
        this.mainQubit = 0;
    }

    /** {@inheritDoc} */
    @Override
    public int getMainQubitIndex() {
        return mainQubit;
    }

    /** {@inheritDoc} */
    @Override
    public void setAdditionalQubit(int idx, int cnt) {
        this.affected.add(idx);
    }

    /**
     * <p>getQubits.</p>
     *
     * @return a int
     */
    public int getQubits() {
        return span;
    }

    /** {@inheritDoc} */
    @Override
    public List<Integer> getAffectedQubitIndexes() {
        return this.affected;
    }

    /** {@inheritDoc} */
    @Override
    public int getHighestAffectedQubitIndex() {
        return Collections.max(getAffectedQubitIndexes());
    }

    /** {@inheritDoc} */
    @Override
    public String getCaption() {
        return this.caption;
    }

    /** {@inheritDoc} */
    @Override
    public String getName() {
        return "Oracle";
    }

    /** {@inheritDoc} */
    @Override
    public String getGroup() {
        return "Oracle";
    }

    /** {@inheritDoc} */
    @Override
    public Complex[][] getMatrix() {
        return matrix;
    }

    // replace null with Complex.ZERO
    private void sanitizeMatrix() {
        int rows = matrix.length;
        for (int i = 0;i < rows; i++) {
            Complex[] row = matrix[i];
            for (int j = 0; j < row.length; j++) {
                if (matrix[i][j] == null) {
                    matrix[i][j] = Complex.ZERO;
                }
            }
        }
    }

    /** {@inheritDoc} */
    @Override
    public void setInverse(boolean inv) {
        if (inv) {
            this.matrix = Complex.conjugateTranspose(matrix);
        }
    }
}