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Implement SHuli's parity_2_offset.
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@vincentmr
vincentmr committed Sep 11, 2024
1 parent acf8b8a commit 3751426
Showing 1 changed file with 17 additions and 33 deletions.
50 changes: 17 additions & 33 deletions ...lightning/core/src/simulators/lightning_qubit/gates/cpu_kernels/GateImplementationsLM.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,15 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
ControlledMatrixOperation::NCMultiQubitOp,
};

static std::size_t parity_2_offset(const std::vector<std::size_t> &parity,
const std::size_t k) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
return offset;
}

/* Matrix gates */

/**
Expand Down Expand Up @@ -411,10 +420,7 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
controlled_values);
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
core_function(arr, indices, offset);
}
}
Expand Down Expand Up @@ -588,10 +594,7 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
const std::size_t i1 = indices[1];
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
core_function(arr, i0 + offset, i1 + offset);
}
} else {
Expand Down Expand Up @@ -1218,10 +1221,7 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
const std::size_t i11 = indices[0B11];
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
core_function(arr, i00 + offset, i01 + offset, i10 + offset,
i11 + offset);
}
Expand Down Expand Up @@ -1653,14 +1653,12 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
const std::size_t i1100 = indices[0B1100];
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
core_function(arr, i0011 + offset, i1100 + offset, indices,
offset);
}
} else {
constexpr std::size_t offset{0U};
constexpr std::size_t one{1U};
const std::array<std::size_t, 4> rev_wires{
num_qubits - wires[3] - 1, num_qubits - wires[2] - 1,
Expand All @@ -1669,7 +1667,6 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
one << rev_wires[0], one << rev_wires[1], one << rev_wires[2],
one << rev_wires[3]};
const auto parity = Pennylane::Util::revWireParity(rev_wires);
const std::size_t offset{0U};
const std::vector<std::size_t> indices{};
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
Expand Down Expand Up @@ -1970,10 +1967,7 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
const std::size_t i1 = indices[(mask << one) | one];
PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
for (std::size_t i = 0; i < indices.size(); i++) {
if ((i >> one) == mask) {
continue;
Expand Down Expand Up @@ -2196,10 +2190,7 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {

PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
const std::size_t offset = parity_2_offset(parity, k);
for (std::size_t i = 0; i < indices.size(); i++) {
if ((i >> two) == mask) {
continue;
Expand Down Expand Up @@ -2480,11 +2471,8 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {

PL_LOOP_PARALLEL(1)
for (std::size_t k = 0; k < exp2(num_qubits - nw_tot); k++) {
const std::size_t offset = parity_2_offset(parity, k);
if constexpr (compute_indices) {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
for (std::size_t i = 0; i < indices.size(); i++) {
if ((i >> 4U) == mask) {
continue;
Expand All @@ -2494,10 +2482,6 @@ class GateImplementationsLM : public PauliGenerator<GateImplementationsLM> {
core_function(arr, i0011 + offset, i1100 + offset, indices,
offset);
} else {
std::size_t offset{0U};
for (std::size_t i = 0; i < parity.size(); i++) {
offset |= ((k << i) & parity[i]);
}
core_function(arr, i0011 + offset, i1100 + offset, indices,
offset);
}
Expand Down

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