/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.math4.legacy.ode.nonstiff;
  
  import org.apache.commons.numbers.core.Sum;
  import org.apache.commons.math4.core.jdkmath.JdkMath;
  import org.apache.commons.math4.legacy.core.Field;
  import org.apache.commons.math4.legacy.core.RealFieldElement;
  import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
  
  /**
   * This class wraps a {@code double} value in an object. It is similar to the
   * standard class {@link Double}, while also implementing the
   * {@link RealFieldElement} interface.
   *
   * @since 3.1
   */
  public class Decimal64 extends Number
                         implements RealFieldElement<Decimal64>, Comparable<Decimal64> {
  
      /** The constant value of {@code 0d} as a {@code Decimal64}. */
      public static final Decimal64 ZERO;
  
      /** The constant value of {@code 1d} as a {@code Decimal64}. */
      public static final Decimal64 ONE;
  
      /**
       * The constant value of {@link Double#NEGATIVE_INFINITY} as a
       * {@code Decimal64}.
       */
      public static final Decimal64 NEGATIVE_INFINITY;
  
      /**
       * The constant value of {@link Double#POSITIVE_INFINITY} as a
       * {@code Decimal64}.
       */
      public static final Decimal64 POSITIVE_INFINITY;
  
      /** The constant value of {@link Double#NaN} as a {@code Decimal64}. */
      public static final Decimal64 NAN;
  
      /** */
      private static final long serialVersionUID = 20120227L;
  
      static {
          ZERO = new Decimal64(0d);
          ONE = new Decimal64(1d);
          NEGATIVE_INFINITY = new Decimal64(Double.NEGATIVE_INFINITY);
          POSITIVE_INFINITY = new Decimal64(Double.POSITIVE_INFINITY);
          NAN = new Decimal64(Double.NaN);
      }
  
      /** The primitive {@code double} value of this object. */
      private final double value;
  
      /**
       * Creates a new instance of this class.
       *
       * @param x the primitive {@code double} value of the object to be created
       */
      public Decimal64(final double x) {
          this.value = x;
      }
  
      /*
       * Methods from the FieldElement interface.
       */
  
      /** {@inheritDoc} */
      @Override
      public Field<Decimal64> getField() {
          return Decimal64Field.getInstance();
      }
  
      /**
       * {@inheritDoc}
       *
       * The current implementation strictly enforces
       * {@code this.add(a).equals(new Decimal64(this.doubleValue()
       * + a.doubleValue()))}.
       */
      @Override
      public Decimal64 add(final Decimal64 a) {
          return new Decimal64(this.value + a.value);
      }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.subtract(a).equals(new Decimal64(this.doubleValue()
      * - a.doubleValue()))}.
      */
     @Override
     public Decimal64 subtract(final Decimal64 a) {
         return new Decimal64(this.value - a.value);
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.negate().equals(new Decimal64(-this.doubleValue()))}.
      */
     @Override
     public Decimal64 negate() {
         return new Decimal64(-this.value);
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.multiply(a).equals(new Decimal64(this.doubleValue()
      * * a.doubleValue()))}.
      */
     @Override
     public Decimal64 multiply(final Decimal64 a) {
         return new Decimal64(this.value * a.value);
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.multiply(n).equals(new Decimal64(n * this.doubleValue()))}.
      */
     @Override
     public Decimal64 multiply(final int n) {
         return new Decimal64(n * this.value);
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.divide(a).equals(new Decimal64(this.doubleValue()
      * / a.doubleValue()))}.
      *
      */
     @Override
     public Decimal64 divide(final Decimal64 a) {
         return new Decimal64(this.value / a.value);
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation strictly enforces
      * {@code this.reciprocal().equals(new Decimal64(1.0
      * / this.doubleValue()))}.
      */
     @Override
     public Decimal64 reciprocal() {
         return new Decimal64(1.0 / this.value);
     }
 
     /*
      * Methods from the Number abstract class
      */
 
     /**
      * {@inheritDoc}
      *
      * The current implementation performs casting to a {@code byte}.
      */
     @Override
     public byte byteValue() {
         return (byte) value;
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation performs casting to a {@code short}.
      */
     @Override
     public short shortValue() {
         return (short) value;
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation performs casting to a {@code int}.
      */
     @Override
     public int intValue() {
         return (int) value;
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation performs casting to a {@code long}.
      */
     @Override
     public long longValue() {
         return (long) value;
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation performs casting to a {@code float}.
      */
     @Override
     public float floatValue() {
         return (float) value;
     }
 
     /** {@inheritDoc} */
     @Override
     public double doubleValue() {
         return value;
     }
 
     /*
      * Methods from the Comparable interface.
      */
 
     /**
      * {@inheritDoc}
      *
      * The current implementation returns the same value as
      * <center> {@code Double.valueOf(this.doubleValue()).compareTo(
      * Double.valueOf(o.doubleValue()))} </center>
      *
      * @see Double#compareTo(Double)
      */
     @Override
     public int compareTo(final Decimal64 o) {
         return Double.compare(this.value, o.value);
     }
 
     /*
      * Methods from the Object abstract class.
      */
 
     /** {@inheritDoc} */
     @Override
     public boolean equals(final Object obj) {
         if (obj instanceof Decimal64) {
             final Decimal64 that = (Decimal64) obj;
             return Double.doubleToLongBits(this.value) == Double
                     .doubleToLongBits(that.value);
         }
         return false;
     }
 
     /**
      * {@inheritDoc}
      *
      * The current implementation returns the same value as
      * {@code new Double(this.doubleValue()).hashCode()}
      *
      * @see Double#hashCode()
      */
     @Override
     public int hashCode() {
         long v = Double.doubleToLongBits(value);
         return (int) (v ^ (v >>> 32));
     }
 
     /**
      * {@inheritDoc}
      *
      * The returned {@code String} is equal to
      * {@code Double.toString(this.doubleValue())}
      *
      * @see Double#toString(double)
      */
     @Override
     public String toString() {
         return Double.toString(value);
     }
 
     /*
      * Methods inspired by the Double class.
      */
 
     /**
      * Returns {@code true} if {@code this} double precision number is infinite
      * ({@link Double#POSITIVE_INFINITY} or {@link Double#NEGATIVE_INFINITY}).
      *
      * @return {@code true} if {@code this} number is infinite
      */
     public boolean isInfinite() {
         return Double.isInfinite(value);
     }
 
     /**
      * Returns {@code true} if {@code this} double precision number is
      * Not-a-Number ({@code NaN}), false otherwise.
      *
      * @return {@code true} if {@code this} is {@code NaN}
      */
     public boolean isNaN() {
         return Double.isNaN(value);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public double getReal() {
         return value;
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 add(final double a) {
         return new Decimal64(value + a);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 subtract(final double a) {
         return new Decimal64(value - a);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 multiply(final double a) {
         return new Decimal64(value * a);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 divide(final double a) {
         return new Decimal64(value / a);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 remainder(final double a) {
         return new Decimal64(JdkMath.IEEEremainder(value, a));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 remainder(final Decimal64 a) {
         return new Decimal64(JdkMath.IEEEremainder(value, a.value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 abs() {
         return new Decimal64(JdkMath.abs(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 ceil() {
         return new Decimal64(JdkMath.ceil(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 floor() {
         return new Decimal64(JdkMath.floor(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 rint() {
         return new Decimal64(JdkMath.rint(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public long round() {
         return JdkMath.round(value);
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 signum() {
         return new Decimal64(JdkMath.signum(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 copySign(final Decimal64 sign) {
         return new Decimal64(JdkMath.copySign(value, sign.value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 copySign(final double sign) {
         return new Decimal64(JdkMath.copySign(value, sign));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 scalb(final int n) {
         return new Decimal64(JdkMath.scalb(value, n));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 hypot(final Decimal64 y) {
         return new Decimal64(JdkMath.hypot(value, y.value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 sqrt() {
         return new Decimal64(JdkMath.sqrt(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 cbrt() {
         return new Decimal64(JdkMath.cbrt(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 rootN(final int n) {
         if (value < 0) {
             return new Decimal64(-JdkMath.pow(-value, 1.0 / n));
         } else {
             return new Decimal64(JdkMath.pow(value, 1.0 / n));
         }
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 pow(final double p) {
         return new Decimal64(JdkMath.pow(value, p));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 pow(final int n) {
         return new Decimal64(JdkMath.pow(value, n));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 pow(final Decimal64 e) {
         return new Decimal64(JdkMath.pow(value, e.value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 exp() {
         return new Decimal64(JdkMath.exp(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 expm1() {
         return new Decimal64(JdkMath.expm1(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 log() {
         return new Decimal64(JdkMath.log(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 log1p() {
         return new Decimal64(JdkMath.log1p(value));
     }
 
     /** Base 10 logarithm.
      * @return base 10 logarithm of the instance
      * @since 3.2
      */
     @Override
     public Decimal64 log10() {
         return new Decimal64(JdkMath.log10(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 cos() {
         return new Decimal64(JdkMath.cos(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 sin() {
         return new Decimal64(JdkMath.sin(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 tan() {
         return new Decimal64(JdkMath.tan(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 acos() {
         return new Decimal64(JdkMath.acos(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 asin() {
         return new Decimal64(JdkMath.asin(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 atan() {
         return new Decimal64(JdkMath.atan(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 atan2(final Decimal64 x) {
         return new Decimal64(JdkMath.atan2(value, x.value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 cosh() {
         return new Decimal64(JdkMath.cosh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 sinh() {
         return new Decimal64(JdkMath.sinh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 tanh() {
         return new Decimal64(JdkMath.tanh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 acosh() {
         return new Decimal64(JdkMath.acosh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 asinh() {
         return new Decimal64(JdkMath.asinh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 atanh() {
         return new Decimal64(JdkMath.atanh(value));
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final Decimal64[] a, final Decimal64[] b)
         throws DimensionMismatchException {
         if (a.length != b.length) {
             throw new DimensionMismatchException(a.length, b.length);
         }
         final double[] aDouble = new double[a.length];
         final double[] bDouble = new double[b.length];
         for (int i = 0; i < a.length; ++i) {
             aDouble[i] = a[i].value;
             bDouble[i] = b[i].value;
         }
         return new Decimal64(Sum.ofProducts(aDouble, bDouble).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final double[] a, final Decimal64[] b)
         throws DimensionMismatchException {
         if (a.length != b.length) {
             throw new DimensionMismatchException(a.length, b.length);
         }
         final double[] bDouble = new double[b.length];
         for (int i = 0; i < a.length; ++i) {
             bDouble[i] = b[i].value;
         }
         return new Decimal64(Sum.ofProducts(a, bDouble).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final Decimal64 a1, final Decimal64 b1,
                                        final Decimal64 a2, final Decimal64 b2) {
         return new Decimal64(Sum.create()
                              .addProduct(a1.value, b1.value)
                              .addProduct(a2.value, b2.value).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final double a1, final Decimal64 b1,
                                        final double a2, final Decimal64 b2) {
         return new Decimal64(Sum.create()
                              .addProduct(a1, b1.value)
                              .addProduct(a2, b2.value).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final Decimal64 a1, final Decimal64 b1,
                                        final Decimal64 a2, final Decimal64 b2,
                                        final Decimal64 a3, final Decimal64 b3) {
         return new Decimal64(Sum.create()
                              .addProduct(a1.value, b1.value)
                              .addProduct(a2.value, b2.value)
                              .addProduct(a3.value, b3.value).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final double a1, final Decimal64 b1,
                                        final double a2, final Decimal64 b2,
                                        final double a3, final Decimal64 b3) {
         return new Decimal64(Sum.create()
                              .addProduct(a1, b1.value)
                              .addProduct(a2, b2.value)
                              .addProduct(a3, b3.value).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final Decimal64 a1, final Decimal64 b1,
                                        final Decimal64 a2, final Decimal64 b2,
                                        final Decimal64 a3, final Decimal64 b3,
                                        final Decimal64 a4, final Decimal64 b4) {
         return new Decimal64(Sum.create()
                              .addProduct(a1.value, b1.value)
                              .addProduct(a2.value, b2.value)
                              .addProduct(a3.value, b3.value)
                              .addProduct(a4.value, b4.value).getAsDouble());
     }
 
     /** {@inheritDoc}
      * @since 3.2
      */
     @Override
     public Decimal64 linearCombination(final double a1, final Decimal64 b1,
                                        final double a2, final Decimal64 b2,
                                        final double a3, final Decimal64 b3,
                                        final double a4, final Decimal64 b4) {
         return new Decimal64(Sum.create()
                              .addProduct(a1, b1.value)
                              .addProduct(a2, b2.value)
                              .addProduct(a3, b3.value)
                              .addProduct(a4, b4.value).getAsDouble());
     }
 }