# mindquantum.core.gates.RX

class mindquantum.core.gates.RX(pr)[source]

Rotation gate around x-axis.

$\begin{split}{\rm RX}=\begin{pmatrix}\cos(\theta/2)&-i\sin(\theta/2)\\ -i\sin(\theta/2)&\cos(\theta/2)\end{pmatrix}\end{split}$

The rotation gate can be initialized in three different ways.

1. If you initialize it with a single number, then it will be a non parameterized gate with a certain rotation angle.

2. If you initialize it with a single str, then it will be a parameterized gate with only one parameter and the default coefficient is one.

3. If you initialize it with a dict, e.g. {‘a’:1,’b’:2}, this gate can have multiple parameters with certain coefficients. In this case, it can be expressed as:

$RX(a+2b)$
Parameters

pr (Union[int, float, str, dict, ParameterResolver]) – the parameters of parameterized gate, see above for detail explanation.

Examples

>>> from mindquantum.core.gates import RX
>>> import numpy as np
>>> rx1 = RX(0.5)
>>> np.round(rx1.matrix(), 2)
array([[0.97+0.j  , 0.  -0.25j],
[0.  -0.25j, 0.97+0.j  ]])
>>> rx2 = RX('a')
>>> np.round(rx2.matrix({'a':0.1}), 3)
array([[0.999+0.j  , 0.   -0.05j],
[0.   -0.05j, 0.999+0.j  ]])
>>> rx3 = RX({'a' : 0.2, 'b': 0.5}).on(0, 2)
>>> print(rx3)
RX(0.2*a + 0.5*b|0 <-: 2)
>>> np.round(rx3.matrix({'a' : 1, 'b' : 2}), 2)
array([[0.83+0.j  , 0.  -0.56j],
[0.  -0.56j, 0.83+0.j  ]])
>>> np.round(rx3.diff_matrix({'a' : 1, 'b' : 2}, about_what = 'a'), 2)
array([[-0.06+0.j  ,  0.  -0.08j],
[ 0.  -0.08j, -0.06+0.j  ]])
>>> rx3.coeff
{'a': 0.2, 'b': 0.5}

get_cpp_obj()[source]

Construct cpp obj.