ParameterVectorElement

Get the index of this element in the parent vector.

Returns the name of the Parameter.

Get the parameters present in the expression.

Returns the UUID of the Parameter.

In advanced use cases, this property can be passed to the Parameter constructor to produce an instance that compares equal to another instance.

Get the parent vector instance.

abs()

Take the absolute value of the expression.

arccos()

Arccosine of the expression.

arcsin()

Arcsine of the expression.

arctan()

Arctangent of the expression.

assign(parameter, value)

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

Parameters

• parameter – A parameter in this expression whose value will be updated.
• value – The new value to bind to.

Returns

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

bind(parameter_values, allow_unknown_parameters=False)

Binds the provided set of parameters to their corresponding values.

Parameters

• parameter_values – Mapping of Parameter instances to the numeric value to which they will be bound.
• allow_unknown_parameters – If False, raises an error if parameter_values contains Parameters in the keys outside those present in the expression. If True, any such parameters are simply ignored.

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.

Returns

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

bind_all(values)

Bind all of the parameters in self to numeric values in the dictionary, returning a numeric value.

This is a special case of bind() which can reach higher performance. It is no problem for the values dictionary to contain parameters that are not used in this expression; the expectation is that the same bindings dictionary will be fed to other expressions as well.

It is an error to call this method with a values dictionary that does not bind all of the values, or to call this method with non-numeric values, but this is not explicitly checked, since this method is intended for performance-sensitive use. Passing an incorrect dictionary may result in unexpected behavior.

Unlike bind(), this method will not raise an exception if non-finite floating-point values are encountered.

Parameters

values – mapping of parameters to numeric values.

conjugate()

Return the complex conjugate of the expression.

cos()

Cosine of the expression.

exp()

Exponentiate the expression.

gradient(param)

Return derivative of this expression with respect to the input parameter.

Parameters

param – The parameter with respect to which the derivative is calculated.

Returns

The derivative as either a constant numeric value or a symbolic ParameterExpression.

is_real()

Check whether the expression represents a real number.

Note that this will return None if there are unbound parameters, in which case it cannot be determined whether the expression is real.

is_symbol()

Check if the expression corresponds to a plain symbol.

Returns

True is this expression corresponds to a symbol, False otherwise.

log()

Take the natural logarithm of the expression.

numeric(strict=True)

Cast this expression to a numeric value.

Parameters

strict – If True (default) this function raises an error if there are any unbound symbols in the expression. If False, this allows casting if the expression represents a numeric value, regardless of unbound symbols. For example (0 * Parameter("x")) is 0 but has the symbol x present.

sign()

Return the sign of the expression.

sin()

Sine of the expression.

subs(parameter_map, allow_unknown_parameters=False)

Returns a new expression with replacement parameters.

Parameters

• parameter_map – Mapping from Parameters in self to the ParameterExpression instances with which they should be replaced.
• allow_unknown_parameters – If False, raises an error if parameter_map contains Parameters in the keys outside those present in the expression. If True, any such parameters are simply ignored.

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.

Returns

A new expression with the specified parameters replaced.

sympify()

Return a SymPy equivalent of this expression.

Returns

A SymPy equivalent of this expression.

tan()

Tangent of the expression.