Package org.apache.commons.math3.linear

Class ArrayRealVector

java.lang.Object
org.apache.commons.math3.linear.RealVector
org.apache.commons.math3.linear.ArrayRealVector
All Implemented Interfaces:
Serializable
public class ArrayRealVector extends RealVector implements Serializable
This class implements the RealVector interface with a double array.
Since:
2.0
See Also:

  • Constructor Details

    • ArrayRealVector

      public ArrayRealVector()
      Build a 0-length vector. Zero-length vectors may be used to initialized construction of vectors by data gathering. We start with zero-length and use either the ArrayRealVector(ArrayRealVector, ArrayRealVector) constructor or one of the append method (append(double), append(ArrayRealVector)) to gather data into this vector.

    • ArrayRealVector

      public ArrayRealVector(int size)
      Construct a vector of zeroes.
      Parameters:
      size - Size of the vector.

    • ArrayRealVector

      public ArrayRealVector(int size, double preset)
      Construct a vector with preset values.
      Parameters:
      size - Size of the vector
      preset - All entries will be set with this value.

    • ArrayRealVector

      public ArrayRealVector(double[] d)
      Construct a vector from an array, copying the input array.
      Parameters:
      d - Array.

    • ArrayRealVector

      public ArrayRealVector(double[] d, boolean copyArray) throws NullArgumentException
      Create a new ArrayRealVector using the input array as the underlying data array. If an array is built specially in order to be embedded in a ArrayRealVector and not used directly, the copyArray may be set to false. This will prevent the copying and improve performance as no new array will be built and no data will be copied.
      Parameters:
      d - Data for the new vector.
      copyArray - if true, the input array will be copied, otherwise it will be referenced.
      Throws:
      NullArgumentException - if d is null.
      See Also:

    • ArrayRealVector

      public ArrayRealVector(double[] d, int pos, int size) throws NullArgumentException, NumberIsTooLargeException
      Construct a vector from part of a array.
      Parameters:
      d - Array.
      pos - Position of first entry.
      size - Number of entries to copy.
      Throws:
      NullArgumentException - if d is null.
      NumberIsTooLargeException - if the size of d is less than pos + size.

    • ArrayRealVector

      public ArrayRealVector(Double[] d)
      Construct a vector from an array.
      Parameters:
      d - Array of Doubles.

    • ArrayRealVector

      public ArrayRealVector(Double[] d, int pos, int size) throws NullArgumentException, NumberIsTooLargeException
      Construct a vector from part of an array.
      Parameters:
      d - Array.
      pos - Position of first entry.
      size - Number of entries to copy.
      Throws:
      NullArgumentException - if d is null.
      NumberIsTooLargeException - if the size of d is less than pos + size.

    • ArrayRealVector

      public ArrayRealVector(RealVector v) throws NullArgumentException
      Construct a vector from another vector, using a deep copy.
      Parameters:
      v - vector to copy.
      Throws:
      NullArgumentException - if v is null.

    • ArrayRealVector

      public ArrayRealVector(ArrayRealVector v) throws NullArgumentException
      Construct a vector from another vector, using a deep copy.
      Parameters:
      v - Vector to copy.
      Throws:
      NullArgumentException - if v is null.

    • ArrayRealVector

      public ArrayRealVector(ArrayRealVector v, boolean deep)
      Construct a vector from another vector.
      Parameters:
      v - Vector to copy.
      deep - If true perform a deep copy, otherwise perform a shallow copy.

    • ArrayRealVector

      public ArrayRealVector(ArrayRealVector v1, ArrayRealVector v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - First vector (will be put in front of the new vector).
      v2 - Second vector (will be put at back of the new vector).

    • ArrayRealVector

      public ArrayRealVector(ArrayRealVector v1, RealVector v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - First vector (will be put in front of the new vector).
      v2 - Second vector (will be put at back of the new vector).

    • ArrayRealVector

      public ArrayRealVector(RealVector v1, ArrayRealVector v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - First vector (will be put in front of the new vector).
      v2 - Second vector (will be put at back of the new vector).

    • ArrayRealVector

      public ArrayRealVector(ArrayRealVector v1, double[] v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - First vector (will be put in front of the new vector).
      v2 - Second vector (will be put at back of the new vector).

    • ArrayRealVector

      public ArrayRealVector(double[] v1, ArrayRealVector v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - First vector (will be put in front of the new vector).
      v2 - Second vector (will be put at back of the new vector).

    • ArrayRealVector

      public ArrayRealVector(double[] v1, double[] v2)
      Construct a vector by appending one vector to another vector.
      Parameters:
      v1 - first vector (will be put in front of the new vector)
      v2 - second vector (will be put at back of the new vector)

  • Method Details

    • copy

      public ArrayRealVector copy()
      Returns a (deep) copy of this vector.
      Specified by:
      copy in class RealVector
      Returns:
      a vector copy.

    • add

      public ArrayRealVector add(RealVector v) throws DimensionMismatchException
      Compute the sum of this vector and v. Returns a new vector. Does not change instance data.
      Overrides:
      add in class RealVector
      Parameters:
      v - Vector to be added.
      Returns:
      this + v.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • subtract

      public ArrayRealVector subtract(RealVector v) throws DimensionMismatchException
      Subtract v from this vector. Returns a new vector. Does not change instance data.
      Overrides:
      subtract in class RealVector
      Parameters:
      v - Vector to be subtracted.
      Returns:
      this - v.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • map

      public ArrayRealVector map(UnivariateFunction function)
      Acts as if implemented as: 
        return copy().mapToSelf(function);
      Returns a new vector. Does not change instance data.
      Overrides:
      map in class RealVector
      Parameters:
      function - Function to apply to each entry.
      Returns:
      a new vector.

    • mapToSelf

      public ArrayRealVector mapToSelf(UnivariateFunction function)
      Acts as if it is implemented as: 
        Entry e = null;
  for(Iterator it = iterator(); it.hasNext(); e = it.next()) {
      e.setValue(function.value(e.getValue()));
  }
      Entries of this vector are modified in-place by this method.
      Overrides:
      mapToSelf in class RealVector
      Parameters:
      function - Function to apply to each entry.
      Returns:
      a reference to this vector.

    • mapAddToSelf

      public RealVector mapAddToSelf(double d)
      Add a value to each entry. The instance is changed in-place.
      Overrides:
      mapAddToSelf in class RealVector
      Parameters:
      d - Value to be added to each entry.
      Returns:
      this.

    • mapSubtractToSelf

      public RealVector mapSubtractToSelf(double d)
      Subtract a value from each entry. The instance is changed in-place.
      Overrides:
      mapSubtractToSelf in class RealVector
      Parameters:
      d - Value to be subtracted.
      Returns:
      this.

    • mapMultiplyToSelf

      public RealVector mapMultiplyToSelf(double d)
      Multiply each entry. The instance is changed in-place.
      Overrides:
      mapMultiplyToSelf in class RealVector
      Parameters:
      d - Multiplication factor.
      Returns:
      this.

    • mapDivideToSelf

      public RealVector mapDivideToSelf(double d)
      Divide each entry by the argument. The instance is changed in-place.
      Overrides:
      mapDivideToSelf in class RealVector
      Parameters:
      d - Value to divide by.
      Returns:
      this.

    • ebeMultiply

      public ArrayRealVector ebeMultiply(RealVector v) throws DimensionMismatchException
      Element-by-element multiplication.
      Specified by:
      ebeMultiply in class RealVector
      Parameters:
      v - Vector by which instance elements must be multiplied
      Returns:
      a vector containing this[i] * v[i] for all i.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • ebeDivide

      public ArrayRealVector ebeDivide(RealVector v) throws DimensionMismatchException
      Element-by-element division.
      Specified by:
      ebeDivide in class RealVector
      Parameters:
      v - Vector by which instance elements must be divided.
      Returns:
      a vector containing this[i] / v[i] for all i.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • getDataRef

      public double[] getDataRef()
      Get a reference to the underlying data array. This method does not make a fresh copy of the underlying data.
      Returns:
      the array of entries.

    • dotProduct

      public double dotProduct(RealVector v) throws DimensionMismatchException
      Compute the dot product of this vector with v.
      Overrides:
      dotProduct in class RealVector
      Parameters:
      v - Vector with which dot product should be computed
      Returns:
      the scalar dot product between this instance and v.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • getNorm

      public double getNorm()
      Returns the L2 norm of the vector.

      The L2 norm is the root of the sum of the squared elements.

      Overrides:
      getNorm in class RealVector
      Returns:
      the norm.
      See Also:

    • getL1Norm

      public double getL1Norm()
      Returns the L1 norm of the vector.

      The L1 norm is the sum of the absolute values of the elements.

      Overrides:
      getL1Norm in class RealVector
      Returns:
      the norm.
      See Also:

    • getLInfNorm

      public double getLInfNorm()
      Returns the L∞ norm of the vector.

      The L∞ norm is the max of the absolute values of the elements.

      Overrides:
      getLInfNorm in class RealVector
      Returns:
      the norm.
      See Also:

    • getDistance

      public double getDistance(RealVector v) throws DimensionMismatchException
      Distance between two vectors.

      This method computes the distance consistent with the L2 norm, i.e. the square root of the sum of element differences, or Euclidean distance.

      Overrides:
      getDistance in class RealVector
      Parameters:
      v - Vector to which distance is requested.
      Returns:
      the distance between two vectors.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.
      See Also:

    • getL1Distance

      public double getL1Distance(RealVector v) throws DimensionMismatchException
      Distance between two vectors.

      This method computes the distance consistent with L1 norm, i.e. the sum of the absolute values of the elements differences.

      Overrides:
      getL1Distance in class RealVector
      Parameters:
      v - Vector to which distance is requested.
      Returns:
      the distance between two vectors.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.

    • getLInfDistance

      public double getLInfDistance(RealVector v) throws DimensionMismatchException
      Distance between two vectors.

      This method computes the distance consistent with L∞ norm, i.e. the max of the absolute values of element differences.

      Overrides:
      getLInfDistance in class RealVector
      Parameters:
      v - Vector to which distance is requested.
      Returns:
      the distance between two vectors.
      Throws:
      DimensionMismatchException - if v is not the same size as this vector.
      See Also:

    • outerProduct

      public RealMatrix outerProduct(RealVector v)
      Compute the outer product.
      Overrides:
      outerProduct in class RealVector
      Parameters:
      v - Vector with which outer product should be computed.
      Returns:
      the matrix outer product between this instance and v.

    • getEntry

      public double getEntry(int index) throws OutOfRangeException
      Return the entry at the specified index.
      Specified by:
      getEntry in class RealVector
      Parameters:
      index - Index location of entry to be fetched.
      Returns:
      the vector entry at index.
      Throws:
      OutOfRangeException - if the index is not valid.
      See Also:

    • getDimension

      public int getDimension()
      Returns the size of the vector.
      Specified by:
      getDimension in class RealVector
      Returns:
      the size of this vector.

    • append

      public RealVector append(RealVector v)
      Construct a new vector by appending a vector to this vector.
      Specified by:
      append in class RealVector
      Parameters:
      v - vector to append to this one.
      Returns:
      a new vector.

    • append

      public ArrayRealVector append(ArrayRealVector v)
      Construct a vector by appending a vector to this vector.
      Parameters:
      v - Vector to append to this one.
      Returns:
      a new vector.

    • append

      public RealVector append(double in)
      Construct a new vector by appending a double to this vector.
      Specified by:
      append in class RealVector
      Parameters:
      in - double to append.
      Returns:
      a new vector.

    • getSubVector

      public RealVector getSubVector(int index, int n) throws OutOfRangeException, NotPositiveException
      Get a subvector from consecutive elements.
      Specified by:
      getSubVector in class RealVector
      Parameters:
      index - index of first element.
      n - number of elements to be retrieved.
      Returns:
      a vector containing n elements.
      Throws:
      OutOfRangeException - if the index is not valid.
      NotPositiveException - if the number of elements is not positive.

    • setEntry

      public void setEntry(int index, double value) throws OutOfRangeException
      Set a single element.
      Specified by:
      setEntry in class RealVector
      Parameters:
      index - element index.
      value - new value for the element.
      Throws:
      OutOfRangeException - if the index is not valid.
      See Also:

    • addToEntry

      public void addToEntry(int index, double increment) throws OutOfRangeException
      Change an entry at the specified index.
      Overrides:
      addToEntry in class RealVector
      Parameters:
      index - Index location of entry to be set.
      increment - Value to add to the vector entry.
      Throws:
      OutOfRangeException - if the index is not valid.

    • setSubVector

      public void setSubVector(int index, RealVector v) throws OutOfRangeException
      Set a sequence of consecutive elements.
      Specified by:
      setSubVector in class RealVector
      Parameters:
      index - index of first element to be set.
      v - vector containing the values to set.
      Throws:
      OutOfRangeException - if the index is not valid.

    • setSubVector

      public void setSubVector(int index, double[] v) throws OutOfRangeException
      Set a set of consecutive elements.
      Parameters:
      index - Index of first element to be set.
      v - Vector containing the values to set.
      Throws:
      OutOfRangeException - if the index is inconsistent with the vector size.

    • set

      public void set(double value)
      Set all elements to a single value.
      Overrides:
      set in class RealVector
      Parameters:
      value - Single value to set for all elements.

    • toArray

      public double[] toArray()
      Convert the vector to an array of doubles. The array is independent from this vector data: the elements are copied.
      Overrides:
      toArray in class RealVector
      Returns:
      an array containing a copy of the vector elements.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • checkVectorDimensions

      protected void checkVectorDimensions(RealVector v) throws DimensionMismatchException
      Check if instance and specified vectors have the same dimension.
      Overrides:
      checkVectorDimensions in class RealVector
      Parameters:
      v - Vector to compare instance with.
      Throws:
      DimensionMismatchException - if the vectors do not have the same dimension.

    • checkVectorDimensions

      protected void checkVectorDimensions(int n) throws DimensionMismatchException
      Check if instance dimension is equal to some expected value.
      Overrides:
      checkVectorDimensions in class RealVector
      Parameters:
      n - Expected dimension.
      Throws:
      DimensionMismatchException - if the dimension is inconsistent with vector size.

    • isNaN

      public boolean isNaN()
      Check if any coordinate of this vector is NaN.
      Specified by:
      isNaN in class RealVector
      Returns:
      true if any coordinate of this vector is NaN, false otherwise.

    • isInfinite

      public boolean isInfinite()
      Check whether any coordinate of this vector is infinite and none are NaN.
      Specified by:
      isInfinite in class RealVector
      Returns:
      true if any coordinate of this vector is infinite and none are NaN, false otherwise.

    • equals

      public boolean equals(Object other)

      Test for the equality of two real vectors. If all coordinates of two real vectors are exactly the same, and none are NaN, the two real vectors are considered to be equal. NaN coordinates are considered to affect globally the vector and be equals to each other - i.e, if either (or all) coordinates of the real vector are equal to NaN, the real vector is equal to a vector with all NaN coordinates.

      This method must be overriden by concrete subclasses of RealVector (the current implementation throws an exception).

      Overrides:
      equals in class RealVector
      Parameters:
      other - Object to test for equality.
      Returns:
      true if two vector objects are equal, false if other is null, not an instance of RealVector, or not equal to this RealVector instance.

    • hashCode

      public int hashCode()
      . This method must be overriden by concrete subclasses of RealVector (current implementation throws an exception). All NaN values have the same hash code.
      Overrides:
      hashCode in class RealVector

    • combine

      public ArrayRealVector combine(double a, double b, RealVector y) throws DimensionMismatchException
      Returns a new vector representing a * this + b * y, the linear combination of this and y. Returns a new vector. Does not change instance data.
      Overrides:
      combine in class RealVector
      Parameters:
      a - Coefficient of this.
      b - Coefficient of y.
      y - Vector with which this is linearly combined.
      Returns:
      a vector containing a * this[i] + b * y[i] for all i.
      Throws:
      DimensionMismatchException - if y is not the same size as this vector.

    • combineToSelf

      public ArrayRealVector combineToSelf(double a, double b, RealVector y) throws DimensionMismatchException
      Updates this with the linear combination of this and y.
      Overrides:
      combineToSelf in class RealVector
      Parameters:
      a - Weight of this.
      b - Weight of y.
      y - Vector with which this is linearly combined.
      Returns:
      this, with components equal to a * this[i] + b * y[i] for all i.
      Throws:
      DimensionMismatchException - if y is not the same size as this vector.

    • walkInDefaultOrder

      public double walkInDefaultOrder(RealVectorPreservingVisitor visitor)
      Visits (but does not alter) all entries of this vector in default order (increasing index).
      Overrides:
      walkInDefaultOrder in class RealVector
      Parameters:
      visitor - the visitor to be used to process the entries of this vector
      Returns:
      the value returned by RealVectorPreservingVisitor.end() at the end of the walk

    • walkInDefaultOrder

      public double walkInDefaultOrder(RealVectorPreservingVisitor visitor, int start, int end) throws NumberIsTooSmallException, OutOfRangeException
      Visits (but does not alter) some entries of this vector in default order (increasing index).
      Overrides:
      walkInDefaultOrder in class RealVector
      Parameters:
      visitor - visitor to be used to process the entries of this vector
      start - the index of the first entry to be visited
      end - the index of the last entry to be visited (inclusive)
      Returns:
      the value returned by RealVectorPreservingVisitor.end() at the end of the walk
      Throws:
      NumberIsTooSmallException - if end < start.
      OutOfRangeException - if the indices are not valid.

    • walkInOptimizedOrder

      public double walkInOptimizedOrder(RealVectorPreservingVisitor visitor)
      Visits (but does not alter) all entries of this vector in optimized order. The order in which the entries are visited is selected so as to lead to the most efficient implementation; it might depend on the concrete implementation of this abstract class. In this implementation, the optimized order is the default order.
      Overrides:
      walkInOptimizedOrder in class RealVector
      Parameters:
      visitor - the visitor to be used to process the entries of this vector
      Returns:
      the value returned by RealVectorPreservingVisitor.end() at the end of the walk

    • walkInOptimizedOrder

      public double walkInOptimizedOrder(RealVectorPreservingVisitor visitor, int start, int end) throws NumberIsTooSmallException, OutOfRangeException
      Visits (but does not alter) some entries of this vector in optimized order. The order in which the entries are visited is selected so as to lead to the most efficient implementation; it might depend on the concrete implementation of this abstract class. In this implementation, the optimized order is the default order.
      Overrides:
      walkInOptimizedOrder in class RealVector
      Parameters:
      visitor - visitor to be used to process the entries of this vector
      start - the index of the first entry to be visited
      end - the index of the last entry to be visited (inclusive)
      Returns:
      the value returned by RealVectorPreservingVisitor.end() at the end of the walk
      Throws:
      NumberIsTooSmallException - if end < start.
      OutOfRangeException - if the indices are not valid.

    • walkInDefaultOrder

      public double walkInDefaultOrder(RealVectorChangingVisitor visitor)
      Visits (and possibly alters) all entries of this vector in default order (increasing index).
      Overrides:
      walkInDefaultOrder in class RealVector
      Parameters:
      visitor - the visitor to be used to process and modify the entries of this vector
      Returns:
      the value returned by RealVectorChangingVisitor.end() at the end of the walk

    • walkInDefaultOrder

      public double walkInDefaultOrder(RealVectorChangingVisitor visitor, int start, int end) throws NumberIsTooSmallException, OutOfRangeException
      Visits (and possibly alters) some entries of this vector in default order (increasing index).
      Overrides:
      walkInDefaultOrder in class RealVector
      Parameters:
      visitor - visitor to be used to process the entries of this vector
      start - the index of the first entry to be visited
      end - the index of the last entry to be visited (inclusive)
      Returns:
      the value returned by RealVectorChangingVisitor.end() at the end of the walk
      Throws:
      NumberIsTooSmallException - if end < start.
      OutOfRangeException - if the indices are not valid.

    • walkInOptimizedOrder

      public double walkInOptimizedOrder(RealVectorChangingVisitor visitor)
      Visits (and possibly alters) all entries of this vector in optimized order. The order in which the entries are visited is selected so as to lead to the most efficient implementation; it might depend on the concrete implementation of this abstract class. In this implementation, the optimized order is the default order.
      Overrides:
      walkInOptimizedOrder in class RealVector
      Parameters:
      visitor - the visitor to be used to process the entries of this vector
      Returns:
      the value returned by RealVectorChangingVisitor.end() at the end of the walk

    • walkInOptimizedOrder

      public double walkInOptimizedOrder(RealVectorChangingVisitor visitor, int start, int end) throws NumberIsTooSmallException, OutOfRangeException
      Visits (and possibly change) some entries of this vector in optimized order. The order in which the entries are visited is selected so as to lead to the most efficient implementation; it might depend on the concrete implementation of this abstract class. In this implementation, the optimized order is the default order.
      Overrides:
      walkInOptimizedOrder in class RealVector
      Parameters:
      visitor - visitor to be used to process the entries of this vector
      start - the index of the first entry to be visited
      end - the index of the last entry to be visited (inclusive)
      Returns:
      the value returned by RealVectorChangingVisitor.end() at the end of the walk
      Throws:
      NumberIsTooSmallException - if end < start.
      OutOfRangeException - if the indices are not valid.