Skip to content

Check qubit arity & bounds in qsim parser #1122

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mhucka wants to merge 1 commit into
base: master
Choose a base branch
from
+450 −44
Open

Check qubit arity & bounds in qsim parser #1122

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
190 changes: 146 additions & 44 deletions tensorflow_quantum/core/src/circuit_parser_qsim.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@ limitations under the License.

#include "tensorflow_quantum/core/src/circuit_parser_qsim.h"

#include <algorithm>
#include <initializer_list>
#include <string>
#include <vector>

Expand All @@ -28,6 +30,7 @@ limitations under the License.
#include "../qsim/lib/io.h"
#include "absl/container/flat_hash_map.h"
#include "absl/strings/numbers.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/types/optional.h"
Expand Down Expand Up @@ -81,6 +84,51 @@ inline Status ParseProtoArg(
return ::tensorflow::Status();
}

// Parses the qubit ids of `op` into indices in [0, num_qubits). `op` must act
// on exactly `qubits.size()` distinct qubits.
//
// Ids reaching the parser are normally decimal indices written by
// ResolveQubitIds, but they end up as raw offsets into simulator memory, so
// nothing is taken on trust here: a missing, extra, unparseable, negative,
// out-of-range, or repeated id is reported as an error instead of becoming an
// out-of-bounds access downstream.
inline Status ParseQubitIds(const Operation& op, const unsigned int num_qubits,
std::initializer_list<unsigned int*> qubits) {
if (op.qubits_size() != static_cast<int>(qubits.size())) {
return Status(
absl::StatusCode::kInvalidArgument,
absl::StrCat("Operation ", op.gate().id(), " expects ", qubits.size(),
" qubit(s) but got ", op.qubits_size(), "."));
}
// Slots [0, i) of `parsed` hold validated indices by the time slot i is
// filled, so the distinctness check only ever compares validated values.
unsigned int* const* const parsed = qubits.begin();
for (int i = 0; i < op.qubits_size(); i++) {
unsigned int* qubit = parsed[i];
const std::string& id = op.qubits(i).id();
// SimpleAtoi into an unsigned target also rejects negative values. It
// tolerates surrounding whitespace and a leading '+', which is harmless
// because the parsed value is range-checked.
if (!absl::SimpleAtoi(id, qubit) || *qubit >= num_qubits) {
return Status(
absl::StatusCode::kInvalidArgument,
absl::StrCat("Invalid qubit id: '", id, "' in operation ",
op.gate().id(), ". Expected an integer in [0, ",
num_qubits, ")."));
}
// qsim's index arithmetic assumes that the qubits of a gate are distinct.
for (int j = 0; j < i; j++) {
if (*parsed[j] == *qubit) {
return Status(
absl::StatusCode::kInvalidArgument,
absl::StrCat("Duplicate qubit id: '", id, "'. Operation ",
op.gate().id(), " must act on distinct qubits."));
}
}
}
return ::tensorflow::Status();
}

inline Status ParseProtoControls(const Operation& op,
const unsigned int num_qubits,
std::vector<unsigned int>* control_qubits,
Expand Down Expand Up @@ -111,9 +159,14 @@ inline Status ParseProtoControls(const Operation& op,
unsigned int tmp;
control_qubits->reserve(control_toks.size());
for (auto tok : control_toks) {
// don't bother error checking since this is done earlier
// in program_resolution.
valid = absl::SimpleAtoi(tok, &tmp);
if (!valid || tmp >= num_qubits) {
return Status(
absl::StatusCode::kInvalidArgument,
absl::StrCat("Invalid control qubit id: '", tok, "' in operation ",
op.gate().id(), ". Expected an integer in [0, ",
num_qubits, ")."));
}
control_qubits->push_back(num_qubits - tmp - 1);
}
control_values->reserve(control_v_toks.size());
Expand Down Expand Up @@ -141,6 +194,26 @@ inline Status OptionalInsertControls(const Operation& op,
if (control_qubits.empty()) {
return ::tensorflow::Status();
}
// qsim's index arithmetic assumes that the control qubits of a gate are
// distinct from each other and from its target qubits.
for (size_t i = 0; i < control_qubits.size(); i++) {
const unsigned int q = control_qubits[i];
const bool is_target = std::find(gate->qubits.begin(), gate->qubits.end(),
q) != gate->qubits.end();
const bool is_repeated =
std::find(control_qubits.begin(), control_qubits.begin() + i, q) !=
control_qubits.begin() + i;
if (is_target || is_repeated) {
// control_qubits holds qsim indices; report the id as written in the
// proto so that the message matches the user's circuit.
const unsigned int proto_id = num_qubits - q - 1;
return Status(
absl::StatusCode::kInvalidArgument,
absl::StrCat("Duplicate control qubit id: '", proto_id,
"'. Control qubits must be distinct from each other "
"and from the target qubits."));
}
}
qsim::MakeControlledGate(control_qubits, control_values, *gate);
return ::tensorflow::Status();
}
Expand All @@ -157,7 +230,10 @@ inline Status SingleConstantGate(
const unsigned int num_qubits, const unsigned int time,
QsimCircuit* circuit, std::vector<GateMetaData>* metadata) {
unsigned int q0;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
Status u = ParseQubitIds(op, num_qubits, {&q0});
if (!u.ok()) {
return u;
}
auto gate = create_f(time, num_qubits - q0 - 1);
Status s = OptionalInsertControls(op, num_qubits, &gate);
if (!s.ok()) {
Expand All @@ -182,8 +258,10 @@ inline Status TwoConstantGate(
const unsigned int num_qubits, const unsigned int time,
QsimCircuit* circuit, std::vector<GateMetaData>* metadata) {
unsigned int q0, q1;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
(void)absl::SimpleAtoi(op.qubits(1).id(), &q1);
Status u = ParseQubitIds(op, num_qubits, {&q0, &q1});
if (!u.ok()) {
return u;
}
auto gate = create_f(time, num_qubits - q0 - 1, num_qubits - q1 - 1);
Status s = OptionalInsertControls(op, num_qubits, &gate);
if (!s.ok()) {
Expand All @@ -209,8 +287,10 @@ inline Status SingleEigenGate(
QsimCircuit* circuit, std::vector<GateMetaData>* metadata) {
unsigned int q0;
float exp, exp_s, gs;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
Status u = ParseQubitIds(op, num_qubits, {&q0});
if (!u.ok()) {
return u;
}

absl::optional<std::string> exponent_symbol;
u = ParseProtoArg(op, "exponent", param_map, &exp, &exponent_symbol);
Expand Down Expand Up @@ -257,9 +337,10 @@ inline Status TwoEigenGate(
QsimCircuit* circuit, std::vector<GateMetaData>* metadata) {
unsigned int q0, q1;
float exp, exp_s, gs;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
(void)absl::SimpleAtoi(op.qubits(1).id(), &q1);
Status u = ParseQubitIds(op, num_qubits, {&q0, &q1});
if (!u.ok()) {
return u;
}

absl::optional<std::string> exponent_symbol;
u = ParseProtoArg(op, "exponent", param_map, &exp, &exponent_symbol);
Expand Down Expand Up @@ -394,10 +475,12 @@ inline Status PhasedXGate(const Operation& op, const SymbolMap& param_map,
const unsigned int num_qubits,
const unsigned int time, QsimCircuit* circuit,
std::vector<GateMetaData>* metadata) {
int q0;
unsigned int q0;
float pexp, pexp_s, exp, exp_s, gs;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
Status u = ParseQubitIds(op, num_qubits, {&q0});
if (!u.ok()) {
return u;
}

absl::optional<std::string> exponent_symbol;
u = ParseProtoArg(op, "exponent", param_map, &exp, &exponent_symbol);
Expand Down Expand Up @@ -453,11 +536,12 @@ inline Status FsimGate(const Operation& op, const SymbolMap& param_map,
const unsigned int num_qubits, const unsigned int time,
QsimCircuit* circuit,
std::vector<GateMetaData>* metadata) {
int q0, q1;
unsigned int q0, q1;
float theta, theta_s, phi, phi_s;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
(void)absl::SimpleAtoi(op.qubits(1).id(), &q1);
Status u = ParseQubitIds(op, num_qubits, {&q0, &q1});
if (!u.ok()) {
return u;
}

absl::optional<std::string> theta_symbol;
u = ParseProtoArg(op, "theta", param_map, &theta, &theta_symbol);
Expand Down Expand Up @@ -509,11 +593,12 @@ inline Status PhasedISwapGate(const Operation& op, const SymbolMap& param_map,
const unsigned int num_qubits,
const unsigned int time, QsimCircuit* circuit,
std::vector<GateMetaData>* metadata) {
int q0, q1;
unsigned int q0, q1;
float pexp, pexp_s, exp, exp_s;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q0);
(void)absl::SimpleAtoi(op.qubits(1).id(), &q1);
Status u = ParseQubitIds(op, num_qubits, {&q0, &q1});
if (!u.ok()) {
return u;
}

absl::optional<std::string> exponent_symbol;
u = ParseProtoArg(op, "exponent", param_map, &exp, &exponent_symbol);
Expand Down Expand Up @@ -599,10 +684,12 @@ inline Status AsymmetricDepolarizingChannel(const Operation& op,
const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float p_x, p_y, p_z;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "p_x", {}, &p_x);
u = ParseProtoArg(op, "p_y", {}, &p_y);
Expand All @@ -620,10 +707,12 @@ inline Status DepolarizingChannel(const Operation& op,
const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float p;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "p", {}, &p);
if (!u.ok()) {
Expand All @@ -637,10 +726,12 @@ inline Status DepolarizingChannel(const Operation& op,

inline Status GADChannel(const Operation& op, const unsigned int num_qubits,
const unsigned int time, NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float p, gamma;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "p", {}, &p);
if (!u.ok()) {
Expand All @@ -660,8 +751,11 @@ inline Status GADChannel(const Operation& op, const unsigned int num_qubits,
inline Status ResetChannel(const Operation& op, const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
unsigned int q;
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

auto chan = qsim::Cirq::ResetChannel<float>::Create(time, num_qubits - q - 1);
ncircuit->channels.push_back(chan);
Expand All @@ -672,10 +766,12 @@ inline Status AmplitudeDampingChannel(const Operation& op,
const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float gamma;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "gamma", {}, &gamma);
if (!u.ok()) {
Expand All @@ -691,10 +787,12 @@ inline Status PhaseDampingChannel(const Operation& op,
const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float gamma;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "gamma", {}, &gamma);
if (!u.ok()) {
Expand All @@ -711,10 +809,12 @@ inline Status PhaseFlipChannel(const Operation& op,
const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float p;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "p", {}, &p);
if (!u.ok()) {
Expand All @@ -730,10 +830,12 @@ inline Status PhaseFlipChannel(const Operation& op,
inline Status BitFlipChannel(const Operation& op, const unsigned int num_qubits,
const unsigned int time,
NoisyQsimCircuit* ncircuit) {
int q;
unsigned int q;
float p;
Status u;
(void)absl::SimpleAtoi(op.qubits(0).id(), &q);
Status u = ParseQubitIds(op, num_qubits, {&q});
if (!u.ok()) {
return u;
}

u = ParseProtoArg(op, "p", {}, &p);
if (!u.ok()) {
Expand Down
Loading
Loading