edu.buffalo.fs7.mathlib
Class Braket

java.lang.Object
  |
  +--edu.buffalo.fs7.mathlib.MathObject
        |
        +--edu.buffalo.fs7.mathlib.Argument
              |
              +--edu.buffalo.fs7.mathlib.Vect
                    |
                    +--edu.buffalo.fs7.mathlib.Braket

All Implemented Interfaces:

java.lang.Cloneable

public class Braket

extends Vect

Class representing a mathematical bra or ket object as introduced by the Dirac notation. The basis chosen for this object is the canonical z-axis basis.

It is derived from the class Vect and is the most important object for quantum computations.

The components of the braket are not created before they are actually needed in a computation.

See Also:

Complex.times_(Complex)., BinaryOp

Field Summary

protected boolean	bra holds whether the braket is a bra or a ket.
int	n holds the number of qubits.

Fields inherited from class edu.buffalo.fs7.mathlib.Vect

data, dimension, transpose

Fields inherited from class edu.buffalo.fs7.mathlib.MathObject

mathlib

Constructor Summary

Braket(int n)
constructs an empty ket vector with n qubits and dimension 2^n.

Braket(int state, int n)
constructs a basis ket.

Braket(MathObject o)
clone constructor

Method Summary

java.lang.Object	clone() clone method
boolean	equals(MathObject o) equality predicate.
static java.lang.String	getBasisString(int basisState, int n, boolean bra) static method to obtain the string representation of a basis braket.
boolean	isBra()
static Braket	parseBraket(java.lang.String str) parses a braket object from a given string.
static Braket	parseBraket(Vect v) creates a braket object from a Vect object.
java.lang.String	toParseableString() returns a parsable string representation of the braket.
java.lang.String	toString() This method expands the braket in its basis states.
java.lang.String	toString(int length) This method expands the braket in its basis states.
void	transpose() transposes the braket. bra -> ket", ket -> bra".

Methods inherited from class edu.buffalo.fs7.mathlib.Vect

conjugate, getElement, negative, parseVector

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

n

public int n

holds the number of qubits. The dimension is given by 2^n.

bra

protected boolean bra

holds whether the braket is a bra or a ket.

Constructor Detail

Braket

public Braket(MathObject o)

clone constructor

See Also:

Vect.Vect(MathObject)

Braket

public Braket(int n)

constructs an empty ket vector with n qubits and dimension 2^n.

Parameters:

n - number of qubits

Braket

public Braket(int state,
              int n)

constructs a basis ket.

Parameters:

state - 0<= state < 2^n

n - number of qubits

Method Detail

clone

public java.lang.Object clone()

clone method

Overrides:

clone in class Vect

Following copied from class: edu.buffalo.fs7.mathlib.Vect

See Also:

Vect.Vect(MathObject)

isBra

public boolean isBra()

parseBraket

public static Braket parseBraket(Vect v)
                          throws java.lang.IllegalArgumentException

creates a braket object from a Vect object. The transpose property of the vector determines whether the parsed object becomes a bra (transpose = false) or a ket (transpose = true). Throws an IllegalArgumentException if the operation fails.

Parameters:

v - a vect object

Returns:

a braket object

parseBraket

public static Braket parseBraket(java.lang.String str)
                          throws java.lang.NumberFormatException,
                                 java.lang.IllegalArgumentException

parses a braket object from a given string. Possible notations are: |001001> or <101000| (binary) |+> or <-| (only for one qubit brakets!) Throws NumberFormatException or IllegalArgumentException if the operation fails.

Parameters:

str - string to parse

Returns:

the braket object

transpose

public void transpose()

transposes the braket. bra -> ket", ket -> bra". Where " denotes the complex conjugate. In order to transform a bra to a ket, a transpose() operation followed by a conjugate() operation must be performed.

Overrides:

transpose in class Vect

See Also:

Vect.conjugate()

equals

public boolean equals(MathObject o)

equality predicate.

Overrides:

equals in class Vect

Returns:

true if o equals this braket

getBasisString

public static java.lang.String getBasisString(int basisState,
                                              int n,
                                              boolean bra)

static method to obtain the string representation of a basis braket.

Parameters:

basisState - the number of the basisState (0 <= basisState < 2^n)

n - the number of qubits (the length of the binary representation)

bra - determines whether the state is given as bra or ket

Returns:

the string representation of a certain basis state in binary braket notation.

See Also:

toString()

toString

public java.lang.String toString()

This method expands the braket in its basis states. The chosen basis is the canonical z-axis basis.

Overrides:

toString in class Vect

Returns:

the string representation of this braket object

See Also:

toString(int), getBasisString(int,int,boolean)

toString

public java.lang.String toString(int length)

This method expands the braket in its basis states. The chosen basis is the canonical z-axis basis. In contrast to the normal toString() method, this method limits its output to the number given as an argument. This is useful since the string representation grows exponentially with the number of qubits!

Parameters:

length - length of the string after which it is truncated

Returns:

the string representation of this braket object

See Also:

toString()

toParseableString

public java.lang.String toParseableString()

returns a parsable string representation of the braket.

Overrides:

toParseableString in class Vect

Following copied from class: edu.buffalo.fs7.mathlib.Vect

Returns:

parsable string representation of ths vector object.