Measurement and Readout

Mid-Circuit Measurement (SparQ/include/measurement.h)

Seedable measurement / reset / probability query interfaces for sparse states.

Provides first-class, reproducible (seedable) sparse-state operations for dynamic executors (mid-circuit MEASURE / RESET / QIF, etc.):

  • MeasureZ: projective Z-basis measurement, samples according to the Born rule, collapses and renormalizes;

  • Reset: post-measurement classically conditioned flip, forcibly resets a register to a given classical value;

  • Probability: read-only probability query (does not modify the state), used for condition evaluation in dynamic control flow such as QIF/QWHILE, as well as for conformance/compliance tests.

Randomness comes from the qram_simulator::random_engine singleton and can be explicitly seeded via random_engine::set_seed(), making the sampling results of MeasureZ/Reset reproducible (essential for deterministic replay and unit tests of the dynamic executor).

Input validation contract (jointly guaranteed by the constructors and operator()):

  • Every register name/ID must resolve to a register that is currently active in System; unknown names, out-of-range IDs, or IDs already removed by RemoveRegister all throw invalid_argument (ValueError on the Python side) at construction time.

  • The register list within a single constructor call must not contain duplicate IDs (e.g. MeasureZ({"a", "a"})); otherwise invalid_argument is thrown.

  • The target values of Reset and the comparison values of Probability must be representable by the bit width of the corresponding register (i.e. less than 2^size_of(id); unrestricted when size_of(id) == 64), otherwise invalid_argument is thrown – such contradictory targets/values were silently truncated in the old implementation and are part of what this hardening fix covers.

  • MeasureZ (and hence Reset) explicitly validates, before sampling, that the total probability of the input state (the sum of abs(amplitude)^2 over all branches) is finite and deviates from 1 by less than kNormalizationThreshold; otherwise it throws runtime_error (RuntimeError on the Python side), instead of directly comparing the random_engine::uniform01() sample against [0, 1) as the old implementation did – that would silently pile the surplus/deficient probability mass onto the last branch (the fallback branch) when the total probability deviates significantly from 1, producing biased sampling without reporting any error.

Warning

Arbitrary C++ operators produced by pysparq.dynamic_operator.compile_operator() undergo no unitarity proof; it merely runtime-compiles an operator()/dag() pair, and the compiler/binding layer will not (and cannot) statically or dynamically verify that the operator is actually unitary. The QCFD support path (QECC.Lang-driven qfvm/qnls/qham) forbids using compile_operator; all semantics must be expressed through named, testable built-in operators such as the ones in this file, and verified via the conformance test matrix provided by pysparq.conformance.

namespace qram_simulator

QRAM sparse state simulator namespace.

Contains all classes, functions, and data structures related to quantum computing simulation

Variables

constexpr double kNormalizationThreshold = 1e-5

Normalization check threshold.

Before sampling, MeasureZ requires |sum(|amplitude|^2) - 1| < kNormalizationThreshold, consistent with the default threshold (1e-5) of CheckNormalization.

struct MeasureZ
#include <measurement.h>

Projective Z-basis measurement.

Performs a computational-basis (Z-basis) measurement on one or more registers:

  1. Validates that the total probability of the input state is finite and approximately 1 (see the file-level documentation);

  2. Samples one outcome among the basis-state branches according to the Born rule using random_engine::uniform01() (seedable via set_seed);

  3. Removes branches inconsistent with the sampled outcome and renormalizes the remaining amplitudes;

  4. Returns the sampled register values together with the probability of that outcome.

This operation is non-unitary and irreversible (measurement collapse), so no dag() is provided.

Public Functions

MeasureZ(const std::vector<std::string> &register_names)

Constructor (register name list version)

Throws:

invalid_argument – Name not found, or the list contains duplicate registers

MeasureZ(const std::vector<size_t> &register_ids)

Constructor (register ID list version)

Throws:

invalid_argument – ID out of range/inactive, or the list contains duplicate registers

MeasureZ(std::string_view register_name)

Constructor (single register name version)

MeasureZ(size_t register_id)

Constructor (single register ID version)

std::pair<std::vector<uint64_t>, double> operator()(std::vector<System> &state) const

Perform the measurement.

Parameters:

state – System state vector (collapsed and renormalized in place)

Throws:

  • invalid_argument – When the state is empty

  • runtime_error – When the total probability is non-finite or clearly deviates from 1 (see file-level documentation)

Returns:

{list of sampled register values, probability of that outcome}

inline std::pair<std::vector<uint64_t>, double> operator()(SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs to measure.

struct Probability
#include <measurement.h>

Read-only Born probability query.

Computes the probability of the event that the given registers take the given values, without modifying the state in any way. Used for QIF/QWHILE condition evaluation in dynamic executors, Born-rule verification in conformance tests, and estimating branch probabilities before actually measuring/resetting.

Public Functions

explicit Probability(const std::map<std::string_view, uint64_t> &assignments)

Constructor (name -> value map version)

Throws:

invalid_argument – Name not found, or a value exceeds the corresponding register’s bit width

explicit Probability(const std::map<size_t, uint64_t> &assignments)

Constructor (ID -> value map version)

Throws:

invalid_argument – ID out of range/inactive, or a value exceeds the corresponding register’s bit width

Probability(const std::vector<std::string> &register_names, const std::vector<uint64_t> &target_values)

Constructor (name list + value list version)

Throws:

invalid_argument – Name not found, duplicate registers, or a value exceeds the bit width

Probability(const std::vector<size_t> &register_ids, const std::vector<uint64_t> &target_values)

Constructor (ID list + value list version)

Throws:

invalid_argument – ID out of range/inactive, duplicate registers, or a value exceeds the bit width

Probability(std::string_view register_name, uint64_t value)

Constructor (single register name + value)

Throws:

invalid_argument – Name not found, or the value exceeds the register’s bit width

Probability(size_t register_id, uint64_t value)

Constructor (single register ID + value)

Throws:

invalid_argument – ID out of range/inactive, or the value exceeds the register’s bit width

double operator()(const std::vector<System> &state) const

Compute the probability of this assignment combination.

Parameters:

state – System state vector (read-only, not modified)

Returns:

Probability (in [0, 1]; returns 1 for an empty constraint)

inline double operator()(const SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs involved in the query.

std::vector<uint64_t> values

List of target values (one-to-one with registers)

Public Static Functions

static std::map<uint64_t, double> distribution(const std::vector<System> &state, size_t register_id)

Compute the full outcome distribution of a single register (read-only)

Parameters:

  • state – System state vector

  • register_id – Register ID

Throws:

invalid_argument – ID out of range/inactive

Returns:

Mapping from register values to probabilities

static inline std::map<uint64_t, double> distribution(const SparseState &state, size_t register_id)

SparseState version (by ID)

static std::map<uint64_t, double> distribution(const std::vector<System> &state, std::string_view register_name)

By-register-name version.

static inline std::map<uint64_t, double> distribution(const SparseState &state, std::string_view register_name)

SparseState version (by name)

struct Reset
#include <measurement.h>

Seedable RESET (measurement + classically conditioned flip)

Physically, resetting a register that may be in a superposition can only be done by “conditionally flipping according to the classical result after measurement” (matching active reset on real hardware and the semantics of the OriginIR-ext RESET instruction):

  1. Perform one projective measurement (collapse + renormalize) on the target register with MeasureZ;

  2. Since after the collapse the register’s value in all remaining branches equals the measurement outcome, directly overwriting it with the target value is equivalent to a classical bit flip on a definite value; it cannot merge illegally with other branches and is therefore well-defined.

The default target value is 0 (corresponding to RESET to |0>).

Public Functions

explicit Reset(const std::vector<std::string> &register_names)

Constructor (name list, all reset to 0 by default)

Throws:

invalid_argument – Name not found, or the list contains duplicate registers

Reset(const std::vector<std::string> &register_names, const std::vector<uint64_t> &targets)

Constructor (name list + target value list)

Throws:

invalid_argument – Name not found, duplicate registers, or a target value outside the range representable by the corresponding register’s bit width

explicit Reset(const std::vector<size_t> &register_ids)

Constructor (ID list, all reset to 0 by default)

Throws:

invalid_argument – ID out of range/inactive, or the list contains duplicate registers

Reset(const std::vector<size_t> &register_ids, const std::vector<uint64_t> &targets)

Constructor (ID list + target value list)

Throws:

invalid_argument – ID out of range/inactive, duplicate registers, or a target value outside the range representable by the corresponding register’s bit width

explicit Reset(std::string_view register_name, uint64_t target = 0)

Constructor (single register name + target value, default 0)

Throws:

invalid_argument – Name not found, or the target value exceeds the register’s bit width

explicit Reset(size_t register_id, uint64_t target = 0)

Constructor (single register ID + target value, default 0)

Throws:

invalid_argument – ID out of range/inactive, or the target value exceeds the register’s bit width

std::vector<uint64_t> operator()(std::vector<System> &state) const

Perform the reset.

Parameters:

state – System state vector (collapsed, renormalized, and overwritten with target values in place)

Returns:

List of register values measured before the reset (for diagnostics/logging)

inline std::vector<uint64_t> operator()(SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs to reset.

std::vector<uint64_t> target_values

List of reset target values (one-to-one with registers)

Partial Trace and Readout (SparQ/include/partial_trace.h)

Partial trace operation definitions.

Implements partial trace operations on quantum states, used for reduced density matrices and probability computation

namespace qram_simulator

QRAM sparse state simulator namespace.

Contains all classes, functions, and data structures related to quantum computing simulation

struct PartialTrace
#include <partial_trace.h>

Partial trace operation class.

Performs the partial trace operation on the specified registers

Public Functions

PartialTrace(const std::vector<std::string> &partial_trace_register_names)

Constructor (name list version)

Parameters:

partial_trace_register_names – List of register names

PartialTrace(const std::vector<size_t> &partial_trace_register_names)

Constructor (ID list version)

Parameters:

partial_trace_register_names – List of register IDs

PartialTrace(std::string_view partial_trace_register_name)

Constructor (single name version)

Parameters:

partial_trace_register_name – Register name

PartialTrace(size_t partial_trace_register_name)

Constructor (single ID version)

Parameters:

partial_trace_register_name – Register ID

std::pair<std::vector<uint64_t>, double> operator()(std::vector<System> &state) const

Apply the partial trace operation.

Parameters:

state – System state vector

Returns:

List of values and probability after the partial trace

inline std::pair<std::vector<uint64_t>, double> operator()(SparseState &state) const

Apply the partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

List of values and probability after the partial trace

Public Members

std::vector<size_t> partial_trace_registers

List of partial trace register IDs.

struct PartialTraceSelect
#include <partial_trace.h>

Selective partial trace operation class.

Performs the partial trace operation on the specified registers and selects specific values

Public Functions

PartialTraceSelect(const std::map<std::string_view, uint64_t> &partial_traces)

Constructor (name-to-value map version)

Parameters:

partial_traces – Map from register names to values

PartialTraceSelect(const std::map<size_t, uint64_t> &partial_traces)

Constructor (ID-to-value map version)

Parameters:

partial_traces – Map from register IDs to values

PartialTraceSelect(const std::vector<std::string> &partial_trace_regs_, const std::vector<uint64_t> &select_values_)

Constructor (name list and value list version)

Parameters:

  • partial_trace_regs_ – List of register names

  • select_values_ – List of selected values

PartialTraceSelect(const std::vector<size_t> &partial_trace_regs_, const std::vector<uint64_t> &select_values_)

Constructor (ID list and value list version)

Parameters:

  • partial_trace_regs_ – List of register IDs

  • select_values_ – List of selected values

double operator()(std::vector<System> &state) const

Apply the selective partial trace operation.

Parameters:

state – System state vector

Returns:

Probability of the selected states

inline double operator()(SparseState &state) const

Apply the selective partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

Probability of the selected states

Public Members

std::vector<size_t> partial_trace_registers

List of partial trace register IDs.

std::vector<uint64_t> select_values

List of selected values.

struct PartialTraceSelectRange
#include <partial_trace.h>

Range-selective partial trace operation class.

Performs the partial trace operation on the specified register and selects a range of values

Public Functions

inline PartialTraceSelectRange(std::string_view partial_trace_register_, std::pair<size_t, size_t> select_range_)

Constructor (name version)

Parameters:

  • partial_trace_register_ – Register name

  • select_range_ – Selection range [min, max]

inline PartialTraceSelectRange(size_t partial_trace_register_, std::pair<size_t, size_t> select_range_)

Constructor (ID version)

Parameters:

  • partial_trace_register_ – Register ID

  • select_range_ – Selection range [min, max]

double operator()(std::vector<System> &state) const

Apply the range-selective partial trace operation.

Parameters:

state – System state vector

Returns:

Probability of the selected states

inline double operator()(SparseState &state) const

Apply the range-selective partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

Probability of the selected states

Public Members

size_t partial_trace_register

Partial trace register ID.

std::pair<size_t, size_t> select_range

Selection range.

double r = 0.0

Result probability.

中文版 ===

测量与读出

中间电路测量（SparQ/include/measurement.h）

Seedable measurement / reset / probability query interfaces for sparse states.

Provides first-class, reproducible (seedable) sparse-state operations for dynamic executors (mid-circuit MEASURE / RESET / QIF, etc.):

  • MeasureZ: projective Z-basis measurement, samples according to the Born rule, collapses and renormalizes;

  • Reset: post-measurement classically conditioned flip, forcibly resets a register to a given classical value;

  • Probability: read-only probability query (does not modify the state), used for condition evaluation in dynamic control flow such as QIF/QWHILE, as well as for conformance/compliance tests.

Randomness comes from the qram_simulator::random_engine singleton and can be explicitly seeded via random_engine::set_seed(), making the sampling results of MeasureZ/Reset reproducible (essential for deterministic replay and unit tests of the dynamic executor).

Input validation contract (jointly guaranteed by the constructors and operator()):

  • Every register name/ID must resolve to a register that is currently active in System; unknown names, out-of-range IDs, or IDs already removed by RemoveRegister all throw invalid_argument (ValueError on the Python side) at construction time.

  • The register list within a single constructor call must not contain duplicate IDs (e.g. MeasureZ({"a", "a"})); otherwise invalid_argument is thrown.

  • The target values of Reset and the comparison values of Probability must be representable by the bit width of the corresponding register (i.e. less than 2^size_of(id); unrestricted when size_of(id) == 64), otherwise invalid_argument is thrown – such contradictory targets/values were silently truncated in the old implementation and are part of what this hardening fix covers.

  • MeasureZ (and hence Reset) explicitly validates, before sampling, that the total probability of the input state (the sum of abs(amplitude)^2 over all branches) is finite and deviates from 1 by less than kNormalizationThreshold; otherwise it throws runtime_error (RuntimeError on the Python side), instead of directly comparing the random_engine::uniform01() sample against [0, 1) as the old implementation did – that would silently pile the surplus/deficient probability mass onto the last branch (the fallback branch) when the total probability deviates significantly from 1, producing biased sampling without reporting any error.

Warning

Arbitrary C++ operators produced by pysparq.dynamic_operator.compile_operator() undergo no unitarity proof; it merely runtime-compiles an operator()/dag() pair, and the compiler/binding layer will not (and cannot) statically or dynamically verify that the operator is actually unitary. The QCFD support path (QECC.Lang-driven qfvm/qnls/qham) forbids using compile_operator; all semantics must be expressed through named, testable built-in operators such as the ones in this file, and verified via the conformance test matrix provided by pysparq.conformance.

namespace qram_simulator

QRAM sparse state simulator namespace.

Contains all classes, functions, and data structures related to quantum computing simulation

Variables

constexpr double kNormalizationThreshold = 1e-5

Normalization check threshold.

Before sampling, MeasureZ requires |sum(|amplitude|^2) - 1| < kNormalizationThreshold, consistent with the default threshold (1e-5) of CheckNormalization.

struct MeasureZ
#include <measurement.h>

Projective Z-basis measurement.

Performs a computational-basis (Z-basis) measurement on one or more registers:

  1. Validates that the total probability of the input state is finite and approximately 1 (see the file-level documentation);

  2. Samples one outcome among the basis-state branches according to the Born rule using random_engine::uniform01() (seedable via set_seed);

  3. Removes branches inconsistent with the sampled outcome and renormalizes the remaining amplitudes;

  4. Returns the sampled register values together with the probability of that outcome.

This operation is non-unitary and irreversible (measurement collapse), so no dag() is provided.

Public Functions

MeasureZ(const std::vector<std::string> &register_names)

Constructor (register name list version)

Throws:

invalid_argument – Name not found, or the list contains duplicate registers

MeasureZ(const std::vector<size_t> &register_ids)

Constructor (register ID list version)

Throws:

invalid_argument – ID out of range/inactive, or the list contains duplicate registers

MeasureZ(std::string_view register_name)

Constructor (single register name version)

MeasureZ(size_t register_id)

Constructor (single register ID version)

std::pair<std::vector<uint64_t>, double> operator()(std::vector<System> &state) const

Perform the measurement.

Parameters:

state – System state vector (collapsed and renormalized in place)

Throws:

  • invalid_argument – When the state is empty

  • runtime_error – When the total probability is non-finite or clearly deviates from 1 (see file-level documentation)

Returns:

{list of sampled register values, probability of that outcome}

inline std::pair<std::vector<uint64_t>, double> operator()(SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs to measure.

struct Probability
#include <measurement.h>

Read-only Born probability query.

Computes the probability of the event that the given registers take the given values, without modifying the state in any way. Used for QIF/QWHILE condition evaluation in dynamic executors, Born-rule verification in conformance tests, and estimating branch probabilities before actually measuring/resetting.

Public Functions

explicit Probability(const std::map<std::string_view, uint64_t> &assignments)

Constructor (name -> value map version)

Throws:

invalid_argument – Name not found, or a value exceeds the corresponding register’s bit width

explicit Probability(const std::map<size_t, uint64_t> &assignments)

Constructor (ID -> value map version)

Throws:

invalid_argument – ID out of range/inactive, or a value exceeds the corresponding register’s bit width

Probability(const std::vector<std::string> &register_names, const std::vector<uint64_t> &target_values)

Constructor (name list + value list version)

Throws:

invalid_argument – Name not found, duplicate registers, or a value exceeds the bit width

Probability(const std::vector<size_t> &register_ids, const std::vector<uint64_t> &target_values)

Constructor (ID list + value list version)

Throws:

invalid_argument – ID out of range/inactive, duplicate registers, or a value exceeds the bit width

Probability(std::string_view register_name, uint64_t value)

Constructor (single register name + value)

Throws:

invalid_argument – Name not found, or the value exceeds the register’s bit width

Probability(size_t register_id, uint64_t value)

Constructor (single register ID + value)

Throws:

invalid_argument – ID out of range/inactive, or the value exceeds the register’s bit width

double operator()(const std::vector<System> &state) const

Compute the probability of this assignment combination.

Parameters:

state – System state vector (read-only, not modified)

Returns:

Probability (in [0, 1]; returns 1 for an empty constraint)

inline double operator()(const SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs involved in the query.

std::vector<uint64_t> values

List of target values (one-to-one with registers)

Public Static Functions

static std::map<uint64_t, double> distribution(const std::vector<System> &state, size_t register_id)

Compute the full outcome distribution of a single register (read-only)

Parameters:

  • state – System state vector

  • register_id – Register ID

Throws:

invalid_argument – ID out of range/inactive

Returns:

Mapping from register values to probabilities

static inline std::map<uint64_t, double> distribution(const SparseState &state, size_t register_id)

SparseState version (by ID)

static std::map<uint64_t, double> distribution(const std::vector<System> &state, std::string_view register_name)

By-register-name version.

static inline std::map<uint64_t, double> distribution(const SparseState &state, std::string_view register_name)

SparseState version (by name)

struct Reset
#include <measurement.h>

Seedable RESET (measurement + classically conditioned flip)

Physically, resetting a register that may be in a superposition can only be done by “conditionally flipping according to the classical result after measurement” (matching active reset on real hardware and the semantics of the OriginIR-ext RESET instruction):

  1. Perform one projective measurement (collapse + renormalize) on the target register with MeasureZ;

  2. Since after the collapse the register’s value in all remaining branches equals the measurement outcome, directly overwriting it with the target value is equivalent to a classical bit flip on a definite value; it cannot merge illegally with other branches and is therefore well-defined.

The default target value is 0 (corresponding to RESET to |0>).

Public Functions

explicit Reset(const std::vector<std::string> &register_names)

Constructor (name list, all reset to 0 by default)

Throws:

invalid_argument – Name not found, or the list contains duplicate registers

Reset(const std::vector<std::string> &register_names, const std::vector<uint64_t> &targets)

Constructor (name list + target value list)

Throws:

invalid_argument – Name not found, duplicate registers, or a target value outside the range representable by the corresponding register’s bit width

explicit Reset(const std::vector<size_t> &register_ids)

Constructor (ID list, all reset to 0 by default)

Throws:

invalid_argument – ID out of range/inactive, or the list contains duplicate registers

Reset(const std::vector<size_t> &register_ids, const std::vector<uint64_t> &targets)

Constructor (ID list + target value list)

Throws:

invalid_argument – ID out of range/inactive, duplicate registers, or a target value outside the range representable by the corresponding register’s bit width

explicit Reset(std::string_view register_name, uint64_t target = 0)

Constructor (single register name + target value, default 0)

Throws:

invalid_argument – Name not found, or the target value exceeds the register’s bit width

explicit Reset(size_t register_id, uint64_t target = 0)

Constructor (single register ID + target value, default 0)

Throws:

invalid_argument – ID out of range/inactive, or the target value exceeds the register’s bit width

std::vector<uint64_t> operator()(std::vector<System> &state) const

Perform the reset.

Parameters:

state – System state vector (collapsed, renormalized, and overwritten with target values in place)

Returns:

List of register values measured before the reset (for diagnostics/logging)

inline std::vector<uint64_t> operator()(SparseState &state) const

SparseState version.

Public Members

std::vector<size_t> registers

List of register IDs to reset.

std::vector<uint64_t> target_values

List of reset target values (one-to-one with registers)

部分迹与读出（SparQ/include/partial_trace.h）

Partial trace operation definitions.

Implements partial trace operations on quantum states, used for reduced density matrices and probability computation

namespace qram_simulator

QRAM sparse state simulator namespace.

Contains all classes, functions, and data structures related to quantum computing simulation

struct PartialTrace
#include <partial_trace.h>

Partial trace operation class.

Performs the partial trace operation on the specified registers

Public Functions

PartialTrace(const std::vector<std::string> &partial_trace_register_names)

Constructor (name list version)

Parameters:

partial_trace_register_names – List of register names

PartialTrace(const std::vector<size_t> &partial_trace_register_names)

Constructor (ID list version)

Parameters:

partial_trace_register_names – List of register IDs

PartialTrace(std::string_view partial_trace_register_name)

Constructor (single name version)

Parameters:

partial_trace_register_name – Register name

PartialTrace(size_t partial_trace_register_name)

Constructor (single ID version)

Parameters:

partial_trace_register_name – Register ID

std::pair<std::vector<uint64_t>, double> operator()(std::vector<System> &state) const

Apply the partial trace operation.

Parameters:

state – System state vector

Returns:

List of values and probability after the partial trace

inline std::pair<std::vector<uint64_t>, double> operator()(SparseState &state) const

Apply the partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

List of values and probability after the partial trace

Public Members

std::vector<size_t> partial_trace_registers

List of partial trace register IDs.

struct PartialTraceSelect
#include <partial_trace.h>

Selective partial trace operation class.

Performs the partial trace operation on the specified registers and selects specific values

Public Functions

PartialTraceSelect(const std::map<std::string_view, uint64_t> &partial_traces)

Constructor (name-to-value map version)

Parameters:

partial_traces – Map from register names to values

PartialTraceSelect(const std::map<size_t, uint64_t> &partial_traces)

Constructor (ID-to-value map version)

Parameters:

partial_traces – Map from register IDs to values

PartialTraceSelect(const std::vector<std::string> &partial_trace_regs_, const std::vector<uint64_t> &select_values_)

Constructor (name list and value list version)

Parameters:

  • partial_trace_regs_ – List of register names

  • select_values_ – List of selected values

PartialTraceSelect(const std::vector<size_t> &partial_trace_regs_, const std::vector<uint64_t> &select_values_)

Constructor (ID list and value list version)

Parameters:

  • partial_trace_regs_ – List of register IDs

  • select_values_ – List of selected values

double operator()(std::vector<System> &state) const

Apply the selective partial trace operation.

Parameters:

state – System state vector

Returns:

Probability of the selected states

inline double operator()(SparseState &state) const

Apply the selective partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

Probability of the selected states

Public Members

std::vector<size_t> partial_trace_registers

List of partial trace register IDs.

std::vector<uint64_t> select_values

List of selected values.

struct PartialTraceSelectRange
#include <partial_trace.h>

Range-selective partial trace operation class.

Performs the partial trace operation on the specified register and selects a range of values

Public Functions

inline PartialTraceSelectRange(std::string_view partial_trace_register_, std::pair<size_t, size_t> select_range_)

Constructor (name version)

Parameters:

  • partial_trace_register_ – Register name

  • select_range_ – Selection range [min, max]

inline PartialTraceSelectRange(size_t partial_trace_register_, std::pair<size_t, size_t> select_range_)

Constructor (ID version)

Parameters:

  • partial_trace_register_ – Register ID

  • select_range_ – Selection range [min, max]

double operator()(std::vector<System> &state) const

Apply the range-selective partial trace operation.

Parameters:

state – System state vector

Returns:

Probability of the selected states

inline double operator()(SparseState &state) const

Apply the range-selective partial trace operation (sparse state version)

Parameters:

state – Sparse state

Returns:

Probability of the selected states

Public Members

size_t partial_trace_register

Partial trace register ID.

std::pair<size_t, size_t> select_range

Selection range.

double r = 0.0

Result probability.