Commit cb585a05 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

added modular adder 



Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 2c1eb073

examples/arithmetic/integer_add.cpp

+19 −0
Original line number Diff line number Diff line
@@ -6,6 +6,12 @@ __qpu__ void test_add_integer(qreg q) { 
  Measure(q);

}



__qpu__ void test_add_integer_mod(qreg q, qubit anc) {

  H(q[2]); // |000> + |001>

  add_integer_mod(q, anc, 3, 5); // |3 mod 5> and |7 mod 5>

  Measure(q);

  Measure(anc);

}



int main(int argc, char **argv) {

  set_shots(1024);
@@ -19,5 +25,18 @@ int main(int argc, char **argv) { 
  qcor_expect(a.counts()["111"] > 400);

  qcor_expect(a.counts()["110"] > 400);



  // Test modular add

  auto b = qalloc(3);

  auto anc = qalloc(1);

  test_add_integer_mod::print_kernel(b, anc[0]);

  test_add_integer_mod(b, anc[0]);

  // |3 mod 5> and |7 mod 5> == |2> + |3>

  b.print();

  qcor_expect(b.counts().size() == 2);

  qcor_expect(b.counts()["110"] > 400);

  qcor_expect(b.counts()["010"] > 400);

  anc.print();

  // anc returns to 0

  qcor_expect(anc.counts()["0"] == 1024);

  return 0;

}
 
 No newline at end of file

lib/impl/integer_arithmetic.hpp

+32 −1
Original line number Diff line number Diff line
@@ -83,3 +83,34 @@ __qpu__ void add_integer(qreg q, int a) { 
  compute { qft_opt_swap(q, 0); }

  action { phase_add_integer(q, a); }

}



// + a mod N in phase space

// need an additional ancilla qubit since we don't do allocation

// inside a kernel.

// See Fig. 5 of https://arxiv.org/pdf/quant-ph/0205095.pdf

__qpu__ void phase_add_integer_mod(qreg q, qubit anc, int a, int N) {

  Reset(anc);

  phase_add_integer(q, a);

  phase_add_integer::adjoint(q, N);

  qft_opt_swap::adjoint(q, 0);

  X::ctrl(q.tail(), anc);

  qft_opt_swap(q, 0);

  phase_add_integer::ctrl(anc, q, N);

  phase_add_integer::adjoint(q, a);

  qft_opt_swap::adjoint(q, 0);

  X(q.tail());

  X::ctrl(q.tail(), anc);

  X(q.tail());

  qft_opt_swap(q, 0);

  phase_add_integer(q, a);

}



// Add an integer a mod N to the a qubit register:

// |q> --> |q + a mod N>

// TODO: ability to create scratch qubits

__qpu__ void add_integer_mod(qreg q, qubit anc, int a, int N) {

  // Bring it to Fourier basis

  // (IQFT automatically)

  compute { qft_opt_swap(q, 0); }

  action { phase_add_integer_mod(q, anc, a, N); }

}