iSWAP gate implementation using CUDA-Q. The example prepares $\lvert 10\rangle$ and applies iSWAP to produce $i\lvert 01\rangle$.

// Compile: nvq++ main.cpp -o main
// Run:     ./main
 
#include <cudaq.h>
 
struct kernel {
    __qpu__ void operator()() {
        cudaq::qvector<2> q;
        x(q[0]);           // q[0]=|1>, q[1]=|0> => |10>
        iswap(q[0], q[1]); // |10> -> i|01>
        mz(q);
    }
};
 
int main() {
    auto counts = cudaq::sample(kernel{});
    counts.dump();  // 100% |01>  (the i phase is not observable in Z basis)
}