pygsti.modelmembers.states.staticpurestate
¶
The StaticPureState class and supporting functionality.
Module Contents¶
Classes¶
A pure state vector that is completely fixed, or "static" (i.e. that posesses no parameters). |
- class pygsti.modelmembers.states.staticpurestate.StaticPureState(purevec, basis='pp', evotype='default', state_space=None)¶
Bases:
pygsti.modelmembers.states.densestate.DensePureState
A pure state vector that is completely fixed, or “static” (i.e. that posesses no parameters).
- Parameters
vec (array_like or SPAMVec) – a 1D numpy array representing the SPAM operation. The shape of this array sets the dimension of the SPAM op.
basis (Basis or {'pp','gm','std'}, optional) – The basis used to construct the Hilbert-Schmidt space representation of this state as a super-ket.
evotype (Evotype or str, optional) – The evolution type. The special value “default” is equivalent to specifying the value of pygsti.evotypes.Evotype.default_evotype.
state_space (StateSpace, optional) – The state space for this operation. If None a default state space with the appropriate number of qubits is used.
- taylor_order_terms(self, order, max_polynomial_vars=100, return_coeff_polys=False)¶
Get the order-th order Taylor-expansion terms of this state vector.
This function either constructs or returns a cached list of the terms at the given order. Each term is “rank-1”, meaning that it is a state preparation followed by or POVM effect preceded by actions on a density matrix rho of the form:
rho -> A rho B
The coefficients of these terms are typically polynomials of the State’s parameters, where the polynomial’s variable indices index the global parameters of the State’s parent (usually a
Model
) , not the State’s local parameter array (i.e. that returned from to_vector).- Parameters
order (int) – The order of terms to get.
max_polynomial_vars (int, optional) – maximum number of variables the created polynomials can have.
return_coeff_polys (bool) – Whether a parallel list of locally-indexed (using variable indices corresponding to this object’s parameters rather than its parent’s) polynomial coefficients should be returned as well.
- Returns
terms (list) – A list of
RankOneTerm
objects.coefficients (list) – Only present when return_coeff_polys == True. A list of compact polynomial objects, meaning that each element is a (vtape,ctape) 2-tuple formed by concatenating together the output of :method:`Polynomial.compact`.
- _is_similar(self, other, rtol, atol)¶
Returns True if other model member (which it guaranteed to be the same type as self) has the same local structure, i.e., not considering parameter values or submembers