Class ImmutableVector
- java.lang.Object
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- dev.nm.algebra.linear.vector.doubles.ImmutableVector
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- All Implemented Interfaces:
Vector
,AbelianGroup<Vector>
,BanachSpace<Vector,Real>
,HilbertSpace<Vector,Real>
,VectorSpace<Vector,Real>
,DeepCopyable
public class ImmutableVector extends Object implements Vector
This is a read-only view of aVector
instance. It keeps the reference to the instance and delegates all operations to the instance except for set(int, double) which will always result in anVectorAccessException
. It may, however, still be modified indirectly via the reference of the original vector. To ensure complete immutability, an independent copy is needed. That is,
Note that the returned values of all operations (e.g.,ImmutableVector immutable = new ImmutableVector(v.deepCopy());
add
) has the same types as the original ones.
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Constructor Summary
Constructors Constructor Description ImmutableVector(Vector v)
Construct a read-only version of a vector.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Vector
add(double scalar)
Add a constant to all entries in this vector.Vector
add(Vector that)
\(this + that\)double
angle(Vector that)
Measure the angle, \(\theta\), betweenthis
andthat
.ImmutableVector
deepCopy()
The implementation returns an instance created fromthis
by the copy constructor of the class, or justthis
if the instance itself is immutable.Vector
divide(Vector that)
Dividethis
bythat
, entry-by-entry.boolean
equals(Object obj)
double
get(int index)
Get the value at position i.int
hashCode()
double
innerProduct(Vector that)
Inner product in the Euclidean space is the dot product.Vector
minus(double scalar)
Subtract a constant from all entries in this vector.Vector
minus(Vector that)
\(this - that\)Vector
multiply(Vector that)
Multiplythis
bythat
, entry-by-entry.double
norm()
Compute the length or magnitude or Euclidean norm of a vector, namely, \(\|v\|\).double
norm(double p)
Gets the \(L^p\)-norm \(\|v\|_p\) of this vector.Vector
opposite()
Get the opposite of this vector.Vector
pow(double scalar)
Take the exponentiation of all entries in this vector, entry-by-entry.Vector
scaled(double scalar)
Scale this vector by a constant, entry-by-entry.Vector
scaled(Real scalar)
Scale this vector by a constant, entry-by-entry.void
set(int i, double value)
This method is overridden to always throwVectorAccessException
.int
size()
Get the length of this vector.double[]
toArray()
Cast this vector into a 1Ddouble[]
.String
toString()
Vector
ZERO()
Get a 0-vector that has the same length as this vector.
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Constructor Detail
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ImmutableVector
public ImmutableVector(Vector v)
Construct a read-only version of a vector. Note that, however, changing the original vector changes the "immutable" version as well.- Parameters:
v
- a vector
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Method Detail
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set
public final void set(int i, double value)
This method is overridden to always throwVectorAccessException
.- Specified by:
set
in interfaceVector
- Parameters:
i
- the index of the entry to change. The indices are counting from 1, NOT 0.value
- the value to change to- Throws:
VectorAccessException
- always
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size
public int size()
Description copied from interface:Vector
Get the length of this vector.
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get
public double get(int index)
Description copied from interface:Vector
Get the value at position i.
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add
public Vector add(Vector that)
Description copied from interface:Vector
\(this + that\)- Specified by:
add
in interfaceAbelianGroup<Vector>
- Specified by:
add
in interfaceVector
- Parameters:
that
- a vector- Returns:
- \(this + that\)
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minus
public Vector minus(Vector that)
Description copied from interface:Vector
\(this - that\)- Specified by:
minus
in interfaceAbelianGroup<Vector>
- Specified by:
minus
in interfaceVector
- Parameters:
that
- a vector- Returns:
- \(this - that\)
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multiply
public Vector multiply(Vector that)
Description copied from interface:Vector
Multiplythis
bythat
, entry-by-entry.
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divide
public Vector divide(Vector that)
Description copied from interface:Vector
Dividethis
bythat
, entry-by-entry.
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add
public Vector add(double scalar)
Description copied from interface:Vector
Add a constant to all entries in this vector.
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minus
public Vector minus(double scalar)
Description copied from interface:Vector
Subtract a constant from all entries in this vector.
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innerProduct
public double innerProduct(Vector that)
Description copied from interface:Vector
Inner product in the Euclidean space is the dot product.- Specified by:
innerProduct
in interfaceHilbertSpace<Vector,Real>
- Specified by:
innerProduct
in interfaceVector
- Parameters:
that
- a vector- Returns:
- \(this \cdot that\)
- See Also:
- Wikipedia: Dot product
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pow
public Vector pow(double scalar)
Description copied from interface:Vector
Take the exponentiation of all entries in this vector, entry-by-entry.
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scaled
public Vector scaled(double scalar)
Description copied from interface:Vector
Scale this vector by a constant, entry-by-entry. Here is a way to get a unit version of the vector:vector.scaled(1. / vector.norm())
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scaled
public Vector scaled(Real scalar)
Description copied from interface:Vector
Scale this vector by a constant, entry-by-entry. Here is a way to get a unit version of the vector:vector.scaled(1. / vector.norm())
- Specified by:
scaled
in interfaceVector
- Specified by:
scaled
in interfaceVectorSpace<Vector,Real>
- Parameters:
scalar
- a constant- Returns:
- \(c \times this\)
- See Also:
- Wikipedia: Scalar multiplication
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norm
public double norm()
Description copied from interface:Vector
Compute the length or magnitude or Euclidean norm of a vector, namely, \(\|v\|\).- Specified by:
norm
in interfaceBanachSpace<Vector,Real>
- Specified by:
norm
in interfaceVector
- Returns:
- the Euclidean norm
- See Also:
- Wikipedia: Norm (mathematics)
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norm
public double norm(double p)
Description copied from interface:Vector
Gets the \(L^p\)-norm \(\|v\|_p\) of this vector.- When p is finite, \(\|v\|_p = \sum_{i}|v_i^p|^\frac{1}{p}\).
- When p is \(+\infty\) (
Double.POSITIVE_INFINITY
), \(\|v\|_p = \max|v_i|\). - When p is \(-\infty\) (
Double.NEGATIVE_INFINITY
), \(\|v\|_p = \min|v_i|\).
- Specified by:
norm
in interfaceVector
- Parameters:
p
- p ≥ 1, orDouble.POSITIVE_INFINITY
orDouble.NEGATIVE_INFINITY
- Returns:
- \(\|v\|_p\)
- See Also:
- Wikipedia: Norm (mathematics)
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angle
public double angle(Vector that)
Description copied from interface:Vector
Measure the angle, \(\theta\), betweenthis
andthat
. That is, \[ this \cdot that = \|this\| \times \|that\| \times \cos \theta \]
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opposite
public Vector opposite()
Description copied from interface:Vector
Get the opposite of this vector.- Specified by:
opposite
in interfaceAbelianGroup<Vector>
- Specified by:
opposite
in interfaceVector
- Returns:
- -v
- See Also:
- Wikipedia: Additive inverse
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ZERO
public Vector ZERO()
Description copied from interface:Vector
Get a 0-vector that has the same length as this vector.- Specified by:
ZERO
in interfaceAbelianGroup<Vector>
- Specified by:
ZERO
in interfaceVector
- Returns:
- the 0-vector
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toArray
public double[] toArray()
Description copied from interface:Vector
Cast this vector into a 1Ddouble[]
.
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deepCopy
public ImmutableVector deepCopy()
Description copied from interface:DeepCopyable
The implementation returns an instance created fromthis
by the copy constructor of the class, or justthis
if the instance itself is immutable.- Specified by:
deepCopy
in interfaceDeepCopyable
- Specified by:
deepCopy
in interfaceVector
- Returns:
- an independent (deep) copy of the instance
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