QkTargetEntry

typedef struct QkTargetEntry QkTargetEntry

A mapping of qubit arguments and properties representing gate map of the Target. This feature is used due to not having valid native mappings available from C.

Here’s an example of how this structure works:

#include <qiskit.h>
#include <math.h>
 
// Create a Target Entry for a CX Gate
QkTargetEntry *entry = qk_target_entry_new(QkGate_CX);
 
// Add mapping between (0,1) and properties duration of 10e-9 and unknown error.
uint32_t qargs[2] = {0, 1};
qk_target_entry_add_property(entry, qargs, 2, 10e-9, NAN);
 
// Add mapping between Global, and no set duration NAN and error of 0.003)
qk_target_entry_add_property(entry, NULL, 0, NAN, 0.003);

Functions

qk_target_entry_new

QkTargetEntry *qk_target_entry_new(QkGate operation)

Creates an entry to the QkTarget based on a QkGate instance.

Example

QkTargetEntry *entry = qk_target_entry_new(QkGate_H);

Parameters

operation – The QkGate whose properties this target entry defines. If the QkGate takes parameters (which can be checked with qk_gate_num_params) it will be added as a an instruction on the target which accepts any parameter value. If the gate only accepts a fixed parameter value you can use qk_target_entry_new_fixed instead.

Returns

A pointer to the new QkTargetEntry.

qk_target_entry_new_measure

QkTargetEntry *qk_target_entry_new_measure(void)

Creates a new entry for adding a measurement instruction to a QkTarget.

Example

QkTargetEntry *entry = qk_target_entry_new_measure();
// Add fixed duration and error rates from qubits at index 0 to 4.
for (uint32_t i = 0; i < 5; i++) {
    // Measure is a single qubit instruction
    uint32_t qargs[1] = {i};
    qk_target_entry_add_property(entry, qargs, 1, 1.928e-10, 7.9829e-11);
}
 
// Add the entry to a target with 5 qubits
QkTarget *measure_target = qk_target_new(5);
qk_target_add_instruction(measure_target, entry);

Returns

A pointer to the new QkTargetEntry for a measurement instruction.

qk_target_entry_new_reset

QkTargetEntry *qk_target_entry_new_reset(void)

Creates a new entry for adding a reset instruction to a QkTarget.

Example

QkTargetEntry *entry = qk_target_entry_new_reset();
// Add fixed duration and error rates from qubits at index 0 to 2.
for (uint32_t i = 0; i < 3; i++) {
    // Reset is a single qubit instruction
    uint32_t qargs[1] = {i};
    qk_target_entry_add_property(entry, qargs, 1, 1.2e-11, 5.9e-13);
}
 
// Add the entry to a target with 3 qubits
QkTarget *reset_target = qk_target_new(3);
qk_target_add_instruction(reset_target, entry);

Returns

A pointer to the new QkTargetEntry for a reset instruction.

qk_target_entry_new_fixed

QkTargetEntry *qk_target_entry_new_fixed(QkGate operation, double *params)

Creates an entry in the QkTarget based on a QkGate instance with no parameters.

Example

double crx_params[1] = {3.14};
QkTargetEntry *entry = qk_target_entry_new_fixed(QkGate_CRX, crx_params);

Safety

The params type is expected to be a pointer to an array of double where the length matches the expectations of the QkGate. If the array is insufficiently long the behavior of this function is undefined as this will read outside the bounds of the array. It can be a null pointer if there are no params for a given gate. You can check qk_gate_num_params to determine how many qubits are required for a given gate.

Note

Adding a QkGate with regular parameters is not currently supported.

Parameters

operation – The QkGate whose properties this target entry defines.
params – A pointer to the parameters that the instruction is calibrated for.

Returns

A pointer to the new QkTargetEntry.

qk_target_entry_num_properties

size_t qk_target_entry_num_properties(const QkTargetEntry *entry)

Retrieves the number of properties stored in the target entry.

Example

// Create an entry for an H gate
QkTargetEntry *entry = qk_target_entry_new(QkGate_H);
size_t props_size = qk_target_entry_num_properties(entry);

Safety

The behavior is undefined if entry is not a valid, non-null pointer to a QkTargetEntry object.

Parameters

entry – The pointer to the mapping object.

Returns

The number of properties in the QkTargetEntry.

qk_target_entry_free

void qk_target_entry_free(QkTargetEntry *entry)

Frees the entry.

Example

QkTargetEntry *entry = qk_target_entry_new(QkGate_H);
qk_target_entry_free(entry);

Safety

The behavior is undefined if entry is not a valid, non-null pointer to a QkTargetEntry object.

Note

An entry pointer will be freed when added to a QkTarget via qk_target_add_instruction, this function is only meant to be used alternatively if an entry is never added to a QkTarget instance.

Parameters

entry – The pointer to the mapping object to be freed.

qk_target_entry_add_property

QkExitCode qk_target_entry_add_property(QkTargetEntry *entry, uint32_t *qargs, uint32_t num_qubits, double duration, double error)

Adds an instruction property instance based on its assigned qargs.

Example

QkTargetEntry *entry = qk_target_entry_new(QkGate_CX);
uint32_t qargs[2] = {0, 1};
qk_target_entry_add_property(entry, qargs, 2, 0.0, 0.1);

Safety

The behavior is undefined if entry is not a valid, non-null pointer to a QkTargetEntry object.

Parameters

entry – The pointer to the entry object.
qargs – A pointer to the array of uint32_t qubit indices to add the gate on, can be a null pointer to check for global properties.
num_qubits – The length of the qargs array.
duration – The instruction’s duration in seconds on the specific set of qubits.
error – The instruction’s average error rate on the specific set of qubits.