Comparators¶
The following comparators are supported:
- GreaterThan (denoted as '>')
- GreaterEqual (denoted as '>=')
- LessThan (denoted as '<')
- LessEqual (denoted as '<=')
- NotEqual (denoted as '!=')
- Equal (denoted as '==')
Note that integer and fixed-point numbers are represented in a 2-complement method during function evaluation. The binary number is extended in the case of a register size miss-match. For example, the positive signed number \((110)_2=6\) is expressed as \((00110)_2\) when operating with a 5-qubit register. Similarly, the negative signed number \((110)_2=-2\) is expressed as \((11110)_2\).
Examples:
(5 <= 3) = 0
(5 == 5) = 1
(\((011)_2\) == \((11)_2\)) = 1
(signed \((101)_2\) < unsigned \((101)_2\)) = 1
Syntax¶
Function: Equal/NotEqual/GreaterThan/GreaterEqual/LessThan/LessEqual
Parameters:
- left_arg: Union[float, int, FixPointNumber, RegisterUserInput]
- right_arg: Union[float, int, FixPointNumber, RegisterUserInput]
- output_size: Optional[PositiveInt]
- output_name: Optional[str]
{
"function": "Equal",
"function_params": {
"left_arg": 3,
"right_arg": {
"size": 3
}
}
}
Register Names¶
By default, the input registers are called left_arg
and right_arg
. If the name field
of a RegisterUserInput
object is specified, then the name of the register is
determined accordingly. If one of the arguments is a constant then it is not available
as an input register.
The output registers include the result register. By default, its name is determined
by the specific comparator used: is_equal
, is_less_than
, etc. It may be overridden
by the output_name
argument. In addition, the input registers are also available as
output registers, with the same names.
Example 1: Two Register¶
{
"logic_flow": [
{
"function": "Equal",
"function_params": {
"left_arg": {
"size": 5,
"is_signed": true
},
"right_arg": {
"size": 3
}
}
}
]
}
from classiq import Model, QUInt, QSInt
from classiq.builtin_functions import Equal
params = Equal(
left_arg=QSInt(size=5).to_register_user_input(),
right_arg=QUInt(size=3).to_register_user_input(),
)
model = Model()
model.Equal(params)
circuit = model.synthesize()
This example generates a circuit that performs 'equal' between two registers. The left arg is a signed register with 5 qubits and the right arg is an unsigned register with 3 qubits.
Example 2: Integer and Register¶
{
"logic_flow": [
{
"function": "Equal",
"function_params": {
"left_arg": 3,
"right_arg": {
"size": 3
}
}
}
]
}
from classiq import Model, RegisterUserInput
from classiq.builtin_functions import Equal
params = Equal(left_arg=3, right_arg=RegisterUserInput(size=3))
model = Model()
model.Equal(params)
circuit = model.synthesize()
This example generates a circuit that performs 'equal' between a quantum register and an integer. The left arg is an integer equal to three and the right arg is an unsigned quantum register with 3 qubits.