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ParameterExpression

ParameterExpression(symbol_map, expr) GitHub(opens in a new tab)

Bases: object

ParameterExpression class to enable creating expressions of Parameters.

Create a new ParameterExpression.

Not intended to be called directly, but to be instantiated via operations on other Parameter or ParameterExpression objects.

Parameters

  • symbol_map (Dict[Parameter, [ParameterExpression, float, or int]]) – Mapping of Parameter instances to the sympy.Symbol serving as their placeholder in expr.
  • expr (sympy.Expr) – Expression of sympy.Symbol s.

Methods

arccos

ParameterExpression.arccos()

Arccos of a ParameterExpression

arcsin

ParameterExpression.arcsin()

Arcsin of a ParameterExpression

arctan

ParameterExpression.arctan()

Arctan of a ParameterExpression

assign

ParameterExpression.assign(parameter, value)

Assign one parameter to a value, which can either be numeric or another parameter expression.

Parameters

  • parameter (Parameter) – A parameter in this expression whose value will be updated.
  • value (Union[ParameterExpression, float]) – The new value to bind to.

Return type

ParameterExpression

Returns

A new expression parameterized by any parameters which were not bound by assignment.

bind

ParameterExpression.bind(parameter_values)

Binds the provided set of parameters to their corresponding values.

Parameters

parameter_values (Dict) – Mapping of Parameter instances to the numeric value to which they will be bound.

Raises

  • CircuitError

    • If parameter_values contains Parameters outside those in self. - If a non-numeric value is passed in parameter_values.
  • ZeroDivisionError

    • If binding the provided values requires division by zero.

Return type

ParameterExpression

Returns

A new expression parameterized by any parameters which were not bound by parameter_values.

conjugate

ParameterExpression.conjugate()

Return the conjugate.

Return type

ParameterExpression

cos

ParameterExpression.cos()

Cosine of a ParameterExpression

exp

ParameterExpression.exp()

Exponential of a ParameterExpression

gradient

ParameterExpression.gradient(param)

Get the derivative of a parameter expression w.r.t. a specified parameter expression.

Parameters

param (Parameter) – Parameter w.r.t. which we want to take the derivative

Return type

Union[ParameterExpression, complex]

Returns

ParameterExpression representing the gradient of param_expr w.r.t. param or complex or float number

is_real

ParameterExpression.is_real()

Return whether the expression is real

log

ParameterExpression.log()

Logarithm of a ParameterExpression

sin

ParameterExpression.sin()

Sine of a ParameterExpression

subs

ParameterExpression.subs(parameter_map)

Returns a new Expression with replacement Parameters.

Parameters

parameter_map (Dict) – Mapping from Parameters in self to the ParameterExpression instances with which they should be replaced.

Raises

CircuitError

  • If parameter_map contains Parameters outside those in self. - If the replacement Parameters in parameter_map would result in a name conflict in the generated expression.

Return type

ParameterExpression

Returns

A new expression with the specified parameters replaced.

tan

ParameterExpression.tan()

Tangent of a ParameterExpression


Attributes

parameters

Returns a set of the unbound Parameters in the expression.

Return type

Set

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