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_termsmust be a non-null, aligned pointer tolenelements of typeQkBitTerm.indicesmust be a non-null, aligned pointer tolenelements of typeuint32_t.
QkComplex64 coeff
The coefficient of the observable term.
uintptr_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.