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Fix RotationXY gate #88

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Merged
merged 4 commits into from
Jan 10, 2023
Merged

Fix RotationXY gate #88

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b911658
Fix RotationXY bug
gnbaker Dec 28, 2022
09f494e
Fix unit test
gnbaker Dec 28, 2022
94fc6a5
Add parenthesis for gate definition
gnbaker Jan 9, 2023
a593645
Update unit tests
gnbaker Jan 10, 2023
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6 changes: 3 additions & 3 deletions src/qureg_apply1qubitgate.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -461,8 +461,8 @@ void QubitRegister<Type>::ApplyHadamard(unsigned const qubit)
///
/// R_XY(phi, theta) = cos(theta/2) I -i sin(theta/2) (cos(phi) X + sin(phi) Y)
///
/// = | c(t/2) -i s(t/2) (c(p) -i s(p) |
/// | -i s(t/2) (c(p) +i s(p) c(t/2) |
/// = | c(t/2) -i s(t/2) (c(p) -i s(p)) |
/// | -i s(t/2) (c(p) +i s(p)) c(t/2) |
///
/// Or, in other format:
///
Expand All @@ -475,7 +475,7 @@ void QubitRegister<Type>::ApplyRotationXY(unsigned const qubit, BaseType phi, Ba
iqs::TinyMatrix<Type, 2, 2, 32> rxy;
rxy(0, 0) = Type(std::cos(theta / 2.), 0);
rxy(0, 1) = Type(-std::sin(theta / 2.) * std::sin(phi), -std::sin(theta / 2.) * std::cos(phi) );
rxy(0, 1) = Type( std::sin(theta / 2.) * std::sin(phi), -std::sin(theta / 2.) * std::cos(phi) );
rxy(1, 0) = Type( std::sin(theta / 2.) * std::sin(phi), -std::sin(theta / 2.) * std::cos(phi) );
rxy(1, 1) = Type(std::cos(theta / 2.), 0);
Apply1QubitGate(qubit, rxy);
}
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13 changes: 9 additions & 4 deletions unit_test/include/apply_1q_gate_test.hpp
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Expand Up @@ -203,7 +203,9 @@ TEST_F(Apply1QGateTest, RotationXY)
psi.ApplyRotationZ(qubit, -phi);
psi.ApplyRotationX(qubit, -theta);
psi.ApplyRotationZ(qubit, phi);
ASSERT_TRUE( psi.ComputeOverlap(psi_0).real() < 1.-accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).real() - 1) < accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).imag() - 0) < accepted_error_);
ASSERT_TRUE( psi.ComputeOverlap(psi_0).real() > 1.-accepted_error_);
// Apply rotation in the XY plane and then cancel it with two rotations.
phi = 1.1;
theta = 0.13;
Expand All @@ -212,20 +214,23 @@ TEST_F(Apply1QGateTest, RotationXY)
psi.ApplyRotationZ(qubit, -phi);
psi.ApplyRotationX(qubit, -theta);
psi.ApplyRotationZ(qubit, phi);
ASSERT_TRUE( psi.ComputeOverlap(psi_0).real() < 1.-accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).real() - 1) < accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).imag() - 0) < accepted_error_);
// Special case phi=0 corresponding to a X rotation.
phi = 0.;
theta = 0.28;
qubit = 1;
psi.ApplyRotationXY(qubit, phi, theta);
psi.ApplyRotationX(qubit, -theta);
ASSERT_TRUE( psi.ComputeOverlap(psi_0).real() < 1.-accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).real() - 1) < accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).imag() - 0) < accepted_error_);
// Special case phi=pi/2 corresponding to a Y rotation.
phi = M_PI/2;
qubit = 2;
psi.ApplyRotationXY(qubit, phi, theta);
psi.ApplyRotationY(qubit, -theta);
ASSERT_TRUE( psi.ComputeOverlap(psi_0).real() < 1.-accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).real() - 1) < accepted_error_);
ASSERT_TRUE( std::abs(psi.ComputeOverlap(psi_0).imag() - 0) < accepted_error_);
}

//////////////////////////////////////////////////////////////////////////////
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