Function validateAndCreateCustomFullStateDiagMatr

quest/src/api/matrices.cpp:277–316

FullStateDiagMatr validateAndCreateCustomFullStateDiagMatr(int numQubits, int useDistrib, int useGpuAccel, int useMultithread, const char* caller) {
    validate_envIsInit(caller);
    QuESTEnv env = getQuESTEnv();

    // validate parameters before passing them to autodeployer
    validate_newFullStateDiagMatrParams(numQubits, useDistrib, useGpuAccel, useMultithread, caller);

    // overwrite all args left as AUTO_FLAG
    autodep_chooseFullStateDiagMatrDeployment(numQubits, useDistrib, useGpuAccel, useMultithread, env);

    // validation ensures this never overflows
    qindex numElems = powerOf2(numQubits);
    qindex numElemsPerNode = numElems / (useDistrib? env.numNodes : 1); // divides evenly

    // prepare output FullStateDiagMatr (avoiding C++20 designated initialiser)
    FullStateDiagMatr out;
    out.numQubits = numQubits;
    out.numElems = numElems;

    // bind deployments, disabling distribution if using a single MPI node
    out.isGpuAccelerated = useGpuAccel;
    out.isMultithreaded = useMultithread;
    out.isDistributed = useDistrib && (env.numNodes > 1);
    out.numElemsPerNode = numElemsPerNode;

    // allocate (unitialised) flags in the heap so that struct copies are mutable
    out.isApproxUnitary       = util_allocEpsilonSensitiveHeapFlag(); // nullptr if failed
    out.isApproxHermitian     = util_allocEpsilonSensitiveHeapFlag();
    out.isApproxNonZero       = util_allocEpsilonSensitiveHeapFlag();
    out.isStrictlyNonNegative = cpu_allocHeapFlag(); // nullptr if failed
    out.wasGpuSynced          = cpu_allocHeapFlag();

    // allocate 1D memory (nullptr if failed or not allocated)
    out.cpuElems = cpu_allocArray(numElemsPerNode);
    out.gpuElems = (useGpuAccel)? gpu_allocArray(numElemsPerNode) : nullptr;

    validateMatrixAllocs(out, __func__);
    setInitialHeapFlags(out);
    return out;
}

extern "C" FullStateDiagMatr createCustomFullStateDiagMatr(int numQubits, int useDistrib, int useGpuAccel, int useMultithread) {