Synchronisation

Functions for copying memory between a Qureg's CPU (RAM) and GPU (VRAM) memory. More...

Functions
void	syncQuregFromGpu (Qureg qureg)
void	syncQuregToGpu (Qureg qureg)
void	syncSubQuregFromGpu (Qureg qureg, qindex localStartInd, qindex numLocalAmps)
void	syncSubQuregToGpu (Qureg qureg, qindex localStartInd, qindex numLocalAmps)

Detailed Description

Functions for copying memory between a Qureg's CPU (RAM) and GPU (VRAM) memory.

These functions are only necessary when the user wishes to manually probe or modify the Qureg amplitudes (rather than use functions like getQuregAmps() and setQuregAmps()), to ensure that the CPU and GPU copies of the Qureg are identical. These functions have no effect when running without GPU-acceleration, but remain legal and harmless to call, to achieve platform agnosticism.

Function Documentation

syncQuregFromGpu()

void syncQuregFromGpu

(

Qureg

qureg

)

Note

Documentation for this function or struct is under construction!

Warning

This function has not yet been unit tested and may contain bugs. Please use with caution!

Definition at line 416 of file qureg.cpp.

                                   {
    validate_quregFields(qureg, __func__);
 
    // permit this to be called even in non-GPU mode
    if (qureg.isGpuAccelerated)
        gpu_copyGpuToCpu(qureg); // syncs then overwrites all local CPU amps
}

Referenced by TEST_CASE(), and TEST_CASE().

syncQuregToGpu()

void syncQuregToGpu

(

Qureg

qureg

)

Note

Documentation for this function or struct is under construction!

Warning

This function has not yet been unit tested and may contain bugs. Please use with caution!

Definition at line 409 of file qureg.cpp.

                                 {
    validate_quregFields(qureg, __func__);
 
    // permit this to be called even in non-GPU mode
    if (qureg.isGpuAccelerated)
        gpu_copyCpuToGpu(qureg); // syncs then overwrites all local GPU amps
}

syncSubQuregFromGpu()

void syncSubQuregFromGpu	(	Qureg	qureg,
		qindex	localStartInd,
		qindex	numLocalAmps )

Note

Documentation for this function or struct is under construction!

Warning

This function has not yet been unit tested and may contain bugs. Please use with caution!

Definition at line 444 of file qureg.cpp.

                                                                                 {
    validate_quregFields(qureg, __func__);
    validate_localAmpIndices(qureg, localStartInd, numLocalAmps, __func__);
 
    // the above validation communicates for node consensus in
    // distributed settings, because params can differ per-node.
    // note also this function accepts statevectors AND density
    // matrices, because the latter does not need a bespoke
    // (row,col) interface, because the user can only access/modify
    // local density matrix amps via a flat index anyway!
 
    // we permit this function to do nothing when not GPU-accelerated
    if (!qureg.isGpuAccelerated)
        return;
 
    // otherwise, every node merely copies its local subset, which
    // may differ per-node, in an embarrassingly parallel manner
    gpu_copyGpuToCpu(&qureg.gpuAmps[localStartInd], &qureg.cpuAmps[localStartInd], numLocalAmps);
}

syncSubQuregToGpu()

void syncSubQuregToGpu	(	Qureg	qureg,
		qindex	localStartInd,
		qindex	numLocalAmps )

Note

Documentation for this function or struct is under construction!

Warning

This function has not yet been unit tested and may contain bugs. Please use with caution!

Definition at line 425 of file qureg.cpp.

                                                                               {
    validate_quregFields(qureg, __func__);
    validate_localAmpIndices(qureg, localStartInd, numLocalAmps, __func__); 
    
    // the above validation communicates for node consensus in
    // distributed settings, because params can differ per-node.
    // note also this function accepts statevectors AND density
    // matrices, because the latter does not need a bespoke
    // (row,col) interface, because the user can only access/modify
    // local density matrix amps via a flat index anyway!
 
    // we permit this function to do nothing when not GPU-accelerated
    if (!qureg.isGpuAccelerated)
        return;
 
    // otherwise, every node merely copies its local subset, which
    // may differ per-node, in an embarrassingly parallel manner
    gpu_copyCpuToGpu(&qureg.cpuAmps[localStartInd], &qureg.gpuAmps[localStartInd], numLocalAmps);
}