QkObsTerm

This is a group of functions for interacting with an opaque (Rust-space) SparseTerm instance.

Data types

QkObsTerm

struct QkObsTerm

A term in a QkObs.

This contains the coefficient (coeff), the number of qubits of the observable (num_qubits) and pointers to the bit_terms and indices arrays, which have length len. It’s the responsibility of the user that the data is coherent, see also the below section on safety.

Safety

bit_terms must be a non-null, aligned pointer to len elements of type QkBitTerm.
indices must be a non-null, aligned pointer to len elements of type uint32_t.

QkComplex64 coeff

The coefficient of the observable term.

size_t len

Length of the bit_terms and indices arrays.

QkBitTerm *bit_terms

A non-null, aligned pointer to len elements of type QkBitTerm.

uint32_t *indices

A non-null, aligned pointer to len elements of type uint32_t.

uint32_t num_qubits

The number of qubits the observable term is defined on.

Functions

qk_obsterm_str

char *qk_obsterm_str(const QkObsTerm *term)

Return a string representation of the sparse term.

Example

QkObs *obs = qk_obs_identity(100);
QkObsTerm term;
qk_obs_term(obs, 0, &term);
char *string = qk_obsterm_str(&term);
qk_str_free(string);

Safety

Behavior is undefined term is not a valid, non-null pointer to a QkObsTerm.

The string must not be freed with the normal C free, you must use qk_str_free to free the memory consumed by the String. Not calling qk_str_free will lead to a memory leak.

Do not change the length of the string after it’s returned, although values can be mutated.

Parameters

term – A pointer to the term.

Returns

The function exit code. This is >0 if reading the term failed.