QuEST_internal.h File Reference

Internal functions used to implement the public facing API in qubits.h. More...

#include "QuEST_precision.h"

Go to the source code of this file.

Functions
void	phaseGate (MultiQubit multiQubit, const int targetQubit, enum phaseGateType type)
REAL	findProbabilityOfZero (MultiQubit multiQubit, const int measureQubit)
	Measure the probability of a specified qubit being in the zero state. More...
REAL	measureInZero (MultiQubit multiQubit, const int measureQubit)
	Update the state vector to be consistent with measuring measureQubit=0. More...
int	validateMatrixIsUnitary (ComplexMatrix2 u)
int	validateAlphaBeta (Complex alpha, Complex beta)
int	validateUnitVector (REAL ux, REAL uy, REAL uz)
void	exitWithError (int errorCode, const char *func)
void	QuESTAssert (int isValid, int errorCode, const char *func)
unsigned long int	hashString (char *str)

Variables
const char *	errorCodes []

Detailed Description

Internal functions used to implement the public facing API in qubits.h.

Do not call these functions directly.

Definition in file QuEST_internal.h.

Function Documentation

exitWithError()

void exitWithError	(	int	errorCode,
		const char *	func
	)

findProbabilityOfZero()

REAL findProbabilityOfZero	(	MultiQubit	multiQubit,
		const int	measureQubit
	)

Measure the probability of a specified qubit being in the zero state.

Parameters

[in]	multiQubit	object representing the set of qubits
[in]	measureQubit	qubit to measure

Returns

probability of qubit measureQubit being zero

hashString()

unsigned long int hashString

(

char *

str

)

Definition at line 238 of file QuEST.cpp.

Referenced by QuESTSeedRandomDefault().

                                       {
    unsigned long int hash = 5381;
    int c;

    while ((c = *str++))
        hash = ((hash << 5) + hash) + c; /* hash * 33 + c */

    return hash;    
}

measureInZero()

REAL measureInZero	(	MultiQubit	multiQubit,
		const int	measureQubit
	)

Update the state vector to be consistent with measuring measureQubit=0.

Measure in Zero performs an irreversible change to the state vector: it updates the vector according to the event that a zero have been measured on the qubit indicated by measureQubit (where his label starts from 0, of course). It achieves this by setting all inconsistent amplitudes to 0 and then renormalising based on the total probability of measuring measureQubit=0. It then returns the probability of making this measurement.

Parameters

[in,out]	multiQubit	object representing the set of qubits
[in]	measureQubit	qubit to measure

Returns

probability of qubit measureQubit being zero

phaseGate()

void phaseGate	(	MultiQubit	multiQubit,
		const int	targetQubit,
		enum phaseGateType	type
	)

Referenced by sGate(), sigmaZ(), and tGate().

QuESTAssert()

void QuESTAssert	(	int	isValid,
		int	errorCode,
		const char *	func
	)

validateAlphaBeta()

int validateAlphaBeta	(	Complex	alpha,
		Complex	beta
	)

Definition at line 193 of file QuEST.cpp.

References Complex::imag, Complex::real, and REAL_EPS.

                                                  {
    if ( fabs(alpha.real*alpha.real 
        + alpha.imag*alpha.imag
        + beta.real*beta.real 
        + beta.imag*beta.imag - 1) > REAL_EPS ) return 0;
    else return 1;
}

validateMatrixIsUnitary()

int validateMatrixIsUnitary

(

ComplexMatrix2

u

)

Definition at line 168 of file QuEST.cpp.

References Complex::imag, ComplexMatrix2::r0c0, ComplexMatrix2::r0c1, ComplexMatrix2::r1c0, ComplexMatrix2::r1c1, Complex::real, and REAL_EPS.

                                             {

    if ( fabs(u.r0c0.real*u.r0c0.real 
        + u.r0c0.imag*u.r0c0.imag
        + u.r1c0.real*u.r1c0.real
        + u.r1c0.imag*u.r1c0.imag - 1) > REAL_EPS ) return 0;
    // check
    if ( fabs(u.r0c1.real*u.r0c1.real 
        + u.r0c1.imag*u.r0c1.imag
        + u.r1c1.real*u.r1c1.real
        + u.r1c1.imag*u.r1c1.imag - 1) > REAL_EPS ) return 0;

    if ( fabs(u.r0c0.real*u.r0c1.real 
        + u.r0c0.imag*u.r0c1.imag
        + u.r1c0.real*u.r1c1.real
        + u.r1c0.imag*u.r1c1.imag) > REAL_EPS ) return 0;

    if ( fabs(u.r0c1.real*u.r0c0.imag
        - u.r0c0.real*u.r0c1.imag
        + u.r1c1.real*u.r1c0.imag
        - u.r1c0.real*u.r1c1.imag) > REAL_EPS ) return 0;

    return 1;
}

validateUnitVector()

int validateUnitVector	(	REAL	ux,
		REAL	uy,
		REAL	uz
	)

Definition at line 201 of file QuEST.cpp.

References REAL_EPS.

                                                 {
    if ( fabs(sqrt(ux*ux + uy*uy + uz*uz) - 1) > REAL_EPS ) return 0;
    else return 1;
}

Variable Documentation

errorCodes

const char* errorCodes[]

Definition at line 24 of file QuEST.cpp.