Function validate_quregFields

quest/src/core/validation.cpp:1746–1773

 */

void validate_quregFields(Qureg qureg, const char* caller) {

    // attempt to detect the Qureg was not initialised with createQureg by the 
    // struct fields being randomised, and ergo being dimensionally incompatible
    bool valid = true;
    valid &= (qureg.numQubits > 0);
    valid &= (qureg.isDensityMatrix == 0 || qureg.isDensityMatrix == 1);
    valid &= (qureg.numAmps == powerOf2(((qureg.isDensityMatrix)? 2:1) * qureg.numQubits));

    // we do not bother checking slightly more involved fields like numAmpsPerNode

    tokenSubs vars = {
        {"${DENS_MATR}", qureg.isDensityMatrix},
        {"${NUM_QUBITS}", qureg.numQubits},
        {"${NUM_AMPS}", qureg.numAmps}};
        
    assertThat(valid, report::INVALID_QUREG_FIELDS, vars, caller);

    // In theory, we could check qureg's malloc'd pointers are not-NULL.
    // However, this wouldn't catch when Qureg was un-initialised because most
    // compilers will not automatically set struct pointers to NULL (though
    // that scenario will likely have been caught by above checks). It also
    // will not catch that the Qureg has already been validly created then
    // destroyed because the struct pointers will not set to NULL (because
    // C passes a struct copy). So NULL checks could only check for the specific
    // scenario of the user explicitly overwriting valid pointers with NULL - 
    // this is not worth catching (the eventual NULL segfault might be better)
}

void validate_quregIsStateVector(Qureg qureg, const char* caller) {