The StaticPureOp class and supporting functionality.

Module Contents



A unitary operation matrix that is completely fixed, or "static" (i.e. that posesses no parameters).

class pygsti.modelmembers.operations.staticunitaryop.StaticUnitaryOp(m, basis='pp', evotype='default', state_space=None)

Bases: pygsti.modelmembers.operations.denseop.DenseUnitaryOperator, pygsti.modelmembers.errorgencontainer.NoErrorGeneratorInterface

A unitary operation matrix that is completely fixed, or “static” (i.e. that posesses no parameters).


marray_like or LinearOperator

a square 2D array-like or LinearOperator object representing the operation action. The shape of m sets the dimension of the operation.

basisBasis or {‘pp’,’gm’,’std’}, optional

The basis used to construct the Hilbert-Schmidt space representation of this state as a super-operator.

evotypeEvotype or str, optional

The evolution type. The special value “default” is equivalent to specifying the value of pygsti.evotypes.Evotype.default_evotype.

state_spaceStateSpace, optional

The state space for this operation. If None a default state space with the appropriate number of qubits is used.

Initialize a new LinearOperator

property total_term_magnitude

Get the total (sum) of the magnitudes of all this operator’s terms.

The magnitude of a term is the absolute value of its coefficient, so this function returns the number you’d get from summing up the absolute-coefficients of all the Taylor terms (at all orders!) you get from expanding this operator in a Taylor series.



property total_term_magnitude_deriv

The derivative of the sum of all this operator’s terms.

Computes the derivative of the total (sum) of the magnitudes of all this operator’s terms with respect to the operators (local) parameters.

numpy array

An array of length self.num_params

taylor_order_terms(order, max_polynomial_vars=100, return_coeff_polys=False)

Get the order-th order Taylor-expansion terms of this operation.

This function either constructs or returns a cached list of the terms at the given order. Each term is “rank-1”, meaning that its action on a density matrix rho can be written:

rho -> A rho B

The coefficients of these terms are typically polynomials of the operation’s parameters, where the polynomial’s variable indices index the global parameters of the operation’s parent (usually a Model), not the operation’s local parameter array (i.e. that returned from to_vector).


Which order terms (in a Taylor expansion of this LindbladOp) to retrieve.

max_polynomial_varsint, optional

maximum number of variables the created polynomials can have.


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.


A list of RankOneTerm objects.


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 Polynomial.compact().