qiskit.circuit.ParameterExpression
class ParameterExpression(symbol_map, expr)
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
Parameterinstances to thesympy.Symbolserving as their placeholder in expr. - expr (sympy.Expr) – Expression of
sympy.Symbols.
__init__
__init__(symbol_map, expr)
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
Parameterinstances to thesympy.Symbolserving as their placeholder in expr. - expr (sympy.Expr) – Expression of
sympy.Symbols.
Methods
__init__(symbol_map, expr) | Create a new ParameterExpression. |
assign(parameter, value) | Assign one parameter to a value, which can either be numeric or another parameter expression. |
bind(parameter_values) | Binds the provided set of parameters to their corresponding values. |
conjugate() | Return the conjugate, which is the ParameterExpression itself, since it is real. |
subs(parameter_map) | Returns a new Expression with replacement Parameters. |
Attributes
parameters | Returns a set of the unbound Parameters in the expression. |
assign
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,int]) – The new value to bind to.
Return type
ParameterExpression
Returns
A new expression parameterized by any parameters which were not bound by assignment.
bind
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
conjugate()
Return the conjugate, which is the ParameterExpression itself, since it is real.
Return type
ParameterExpression
parameters
Returns a set of the unbound Parameters in the expression.
Return type
Set
subs
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.