Java DoubleUnaryOperator類代碼示例

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
static double integrate(DoubleUnaryOperator f, double a, double b) {
    double dx = (b - a);
    double sum0;
    double sum1 = f.applyAsDouble(a) * (b - a);
    int it = 1;
    do {
        dx /= 2.;
        it *= 2;
        sum0 = sum1;
        sum1 = .0;
        for (double x = a, eps = dx / 2.; x + eps < b; x += dx) {
            sum1 += dx * f.applyAsDouble(x);
        }
    } while (Math.abs(sum0 - sum1) > 1e-7 && it < 100000000);
    return sum1;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@Override
public final DoubleStream map(DoubleUnaryOperator mapper) {
    Objects.requireNonNull(mapper);
    return new StatelessOp<Double>(this, StreamShape.DOUBLE_VALUE,
                                   StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
        @Override
        Sink<Double> opWrapSink(int flags, Sink<Double> sink) {
            return new Sink.ChainedDouble<Double>(sink) {
                @Override
                public void accept(double t) {
                    downstream.accept(mapper.applyAsDouble(t));
                }
            };
        }
    };
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
 * Returns an infinite sequential ordered {@code DoubleStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code DoubleStream}
 * will be the provided {@code seed}.  For {@code n > 0}, the element at
 * position {@code n}, will be the result of applying the function {@code f}
 *  to the element at position {@code n - 1}.
 *
 * @param seed the initial element
 * @param f a function to be applied to to the previous element to produce
 *          a new element
 * @return a new sequential {@code DoubleStream}
 */
public static DoubleStream iterate(final double seed, final DoubleUnaryOperator f) {
    Objects.requireNonNull(f);
    final PrimitiveIterator.OfDouble iterator = new PrimitiveIterator.OfDouble() {
        double t = seed;

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public double nextDouble() {
            double v = t;
            t = f.applyAsDouble(t);
            return v;
        }
    };
    return StreamSupport.doubleStream(Spliterators.spliteratorUnknownSize(
            iterator,
            Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL), false);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
 * Returns an infinite sequential ordered {@code DoubleStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code DoubleStream}
 * will be the provided {@code seed}.  For {@code n > 0}, the element at
 * position {@code n}, will be the result of applying the function {@code f}
 *  to the element at position {@code n - 1}.
 *
 * <p>The action of applying {@code f} for one element
 * <a href="../concurrent/package-summary.html#MemoryVisibility"><i>happens-before</i></a>
 * the action of applying {@code f} for subsequent elements.  For any given
 * element the action may be performed in whatever thread the library
 * chooses.
 *
 * @param seed the initial element
 * @param f a function to be applied to the previous element to produce
 *          a new element
 * @return a new sequential {@code DoubleStream}
 */
public static DoubleStream iterate(final double seed, final DoubleUnaryOperator f) {
    Objects.requireNonNull(f);
    Spliterator.OfDouble spliterator = new Spliterators.AbstractDoubleSpliterator(Long.MAX_VALUE,
           Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL) {
        double prev;
        boolean started;

        @Override
        public boolean tryAdvance(DoubleConsumer action) {
            Objects.requireNonNull(action);
            double t;
            if (started)
                t = f.applyAsDouble(prev);
            else {
                t = seed;
                started = true;
            }
            action.accept(prev = t);
            return true;
        }
    };
    return StreamSupport.doubleStream(spliterator, false);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
 * Returns an infinite sequential ordered {@code DoubleStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code DoubleStream}
 * will be the provided {@code seed}.  For {@code n > 0}, the element at
 * position {@code n}, will be the result of applying the function {@code f}
 *  to the element at position {@code n - 1}.
 *
 * @param seed the initial element
 * @param f a function to be applied to the previous element to produce
 *          a new element
 * @return a new sequential {@code DoubleStream}
 */
public static DoubleStream iterate(final double seed, final DoubleUnaryOperator f) {
    Objects.requireNonNull(f);
    Spliterator.OfDouble spliterator = new Spliterators.AbstractDoubleSpliterator(Long.MAX_VALUE,
           Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL) {
        double prev;
        boolean started;

        @Override
        public boolean tryAdvance(DoubleConsumer action) {
            Objects.requireNonNull(action);
            double t;
            if (started)
                t = f.applyAsDouble(prev);
            else {
                t = seed;
                started = true;
            }
            action.accept(prev = t);
            return true;
        }
    };
    return StreamSupport.doubleStream(spliterator, false);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
*
*/
@Test
@SuppressWarnings(CompilerWarnings.UNUSED)
public void shouldRequireNonNullCache() {
    // given
    final ConcurrentMap<Double, Double> cache = null;
    final DoubleUnaryOperator operator = input -> input;
    final DoubleFunction<Double> keyFunction = Double::valueOf;

    // when
    thrown.expect(NullPointerException.class);
    thrown.expectMessage("Provide an empty map instead of NULL.");

    // then
    new ConcurrentMapBasedDoubleUnaryOperatorMemoizer<>(cache, keyFunction, operator);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
*
*/
@Test
@SuppressWarnings(CompilerWarnings.UNUSED)
public void shouldRequireNonNullOperator() {
    // given
    final ConcurrentMap<Double, Double> cache = new ConcurrentHashMap<>();
    final DoubleUnaryOperator operator = null;
    final DoubleFunction<Double> keyFunction = Double::valueOf;

    // when
    thrown.expect(NullPointerException.class);
    thrown.expectMessage(
            "Cannot memoize a NULL DoubleUnaryOperator - provide an actual DoubleUnaryOperator to fix this.");

    // then
    new ConcurrentMapBasedDoubleUnaryOperatorMemoizer<>(cache, keyFunction, operator);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
*
*/
@Test
public void shouldUseSetCacheKeyAndValue() {
    // given
    final ConcurrentMap<Double, Double> cache = new ConcurrentHashMap<>();
    final DoubleUnaryOperator operator = input -> input;
    final DoubleFunction<Double> keyFunction = Double::valueOf;

    // when
    final ConcurrentMapBasedDoubleUnaryOperatorMemoizer<Double> memoizer = new ConcurrentMapBasedDoubleUnaryOperatorMemoizer<>(
            cache, keyFunction, operator);

    // then
    memoizer.applyAsDouble(123D);
    Assert.assertFalse("Cache is still empty after memoization", memoizer.viewCacheForTest().isEmpty());
    Assert.assertEquals("Memoization key does not match expectations", 123D,
            memoizer.viewCacheForTest().keySet().iterator().next().doubleValue(), 0.0D);
    Assert.assertEquals("Memoization value does not match expectations", 123D,
            memoizer.viewCacheForTest().values().iterator().next().doubleValue(), 0.0D);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
*
*/
@Test
public void shouldUseCallWrappedOperator() {
    // given
    final ConcurrentMap<Double, Double> cache = new ConcurrentHashMap<>();
    final DoubleUnaryOperator operator = Mockito.mock(DoubleUnaryOperator.class);
    final DoubleFunction<Double> keyFunction = Double::valueOf;

    // when
    final ConcurrentMapBasedDoubleUnaryOperatorMemoizer<Double> memoizer = new ConcurrentMapBasedDoubleUnaryOperatorMemoizer<>(
            cache, keyFunction, operator);

    // then
    memoizer.applyAsDouble(123D);
    Mockito.verify(operator).applyAsDouble(123D);
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
/**
 * Construct an instance of the NewtonRaphson method for masochists who
 * do not want to use {@link #builder()}.
 * @param func the function
 * @param derivative the derivative of the function
 * @param tolerance the tolerance
 * @param iterations maximum number of iterations
 */
public NewtonRaphson(
    DoubleUnaryOperator func,
    DoubleUnaryOperator derivative,
    double tolerance,
    long iterations) {
    this.func = func;
    this.derivative = derivative;
    this.tolerance = tolerance;
    this.iterations = iterations;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@NonNull
@Override
public MuVector2d map(@NonNull final DoubleUnaryOperator operator) {
  this.x = operator.applyAsDouble(this.x);
  this.y = operator.applyAsDouble(this.y);
  return this;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@NonNull
@Override
public MuVector3d map(@NonNull final DoubleUnaryOperator operator) {
  this.x = operator.applyAsDouble(this.x);
  this.y = operator.applyAsDouble(this.y);
  this.z = operator.applyAsDouble(this.z);
  return this;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@NonNull
@Override
public MuVector4d map(@NonNull final DoubleUnaryOperator operator) {
  this.x = operator.applyAsDouble(this.x);
  this.y = operator.applyAsDouble(this.y);
  this.z = operator.applyAsDouble(this.z);
  this.w = operator.applyAsDouble(this.w);
  return this;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@NonNull
@Override
public MuVector4f map(@NonNull final DoubleUnaryOperator operator) {
  this.x = (float) operator.applyAsDouble(this.x);
  this.y = (float) operator.applyAsDouble(this.y);
  this.z = (float) operator.applyAsDouble(this.z);
  this.w = (float) operator.applyAsDouble(this.w);
  return this;
}
 

import java.util.function.DoubleUnaryOperator; //導入依賴的package包/類
@NonNull
@Override
public MuVector3f map(@NonNull final DoubleUnaryOperator operator) {
  this.x = (float) operator.applyAsDouble(this.x);
  this.y = (float) operator.applyAsDouble(this.y);
  this.z = (float) operator.applyAsDouble(this.z);
  return this;
}