Synchronisation

Functions for overwriting a channel's GPU (VRAM) memory with its CPU (RAM) contents. More...

Functions
void	syncKrausMap (KrausMap map)
void	syncSuperOp (SuperOp op)

Detailed Description

Functions for overwriting a channel's GPU (VRAM) memory with its CPU (RAM) contents.

These functions are only necessary when the user wishes to manually modify the elements of a channel (in lieu of using the Setters), to thereafter synchronise the changes to the GPU copy of the channel. These functions have no effect when running without GPU-acceleration, but remain legal and harmless to call (to achieve platform agnosticism).

Function Documentation

syncKrausMap()

void syncKrausMap

(

KrausMap

map

)

Updates the internal state of map, necessary after manually modifying KrausMap::matrices.

Parameters

[in,out]

map

the KrausMap to synchronise.

Exceptions

error

if map is uninitialised.

See also

• setKrausMap()
• C or C++ examples

Author

Tyson Jones

Definition at line 236 of file channels.cpp.

                                           {
    validate_krausMapFields(map, __func__);
 
    // re-compute and GPU-sync the superoperator from the modified matrices
    util_setSuperoperator(map.superop.cpuElems, map.matrices, map.numMatrices, map.numQubits);
    syncSuperOp(map.superop);
 
    // indicate that we do not know whether the revised map is
    // is CPTP; we defer establishing that until a CPTP check
    util_setFlagToUnknown(map.isApproxCPTP);
}

Referenced by TEST_CASE().

syncSuperOp()

void syncSuperOp

(

SuperOp

op

)

Updates the internal state of op, necessary after manually modifying SuperOp::cpuElems or SuperOp::cpuElemsFlat.

Parameters

[in,out]

op

the SuperOp to synchronise.

Exceptions

error

if op is uninitialised.

See also

• setSuperOp()
• C or C++ examples

Author

Tyson Jones

Definition at line 223 of file channels.cpp.

                                        {
    validate_superOpFields(op, __func__);
 
    // optionally overwrite GPU elements with user-modified CPU elements
    if (mem_isAllocated(util_getGpuMemPtr(op)))
        gpu_copyCpuToGpu(op);
 
    // indicate that the matrix is now permanently GPU synchronised, even
    // if we are not in GPU-accelerated mode - it hardly matters
    *(op.wasGpuSynced) = 1;
}

Referenced by syncKrausMap(), and TEST_CASE().