Merge pull request #312 from tequilahub/devel

Update Master to v.1.9.0

Author: kottmanj

Diff for: .github/workflows/ci_backends.yml

@@ -32,7 +32,7 @@ jobs:
             # myqlm does not work in python3.7
             pip install "cirq" "qiskit>=0.30" "qulacs" "qibo==0.1.1"
         elif [ $ver -eq 8 ]; then
-            pip install "cirq" "qiskit>=0.30" "qulacs" "qibo==0.1.1" "myqlm"
+            pip install "cirq" "qiskit>=0.30" "qulacs" "qibo==0.1.1" "myqlm" "cirq-google"
         fi
         pip install -e .
     - name: Lint with flake8

Diff for: .github/workflows/ci_chemistry_pyscf.yml

@@ -42,6 +42,6 @@ jobs:
         python -m pip install 'h5py <= 3.1'
         cd tests
         ls
-        pytest test_chemistry.py  -m "not dependencies"
+        pytest test_chemistry.py test_TrotErr.py  -m "not dependencies"
         pytest test_adapt.py  -m "not dependencies"
         cd ../

Diff for: .github/workflows/ci_pyquil.yml

@@ -29,8 +29,9 @@ jobs:
         python -m pip install --upgrade pip
         pip install --upgrade pytest
         pip install -r requirements.txt
-        pip install "pyquil<3.0"
+        pip install "pyquil<3.0" # needs updates
         pip install -e .
+        pip install --upgrade pip 'urllib3<2' # issues with old pyquil version otherwise
         docker pull rigetti/qvm:edge
         docker pull rigetti/quilc
         docker run --rm -itd -p 5555:5555 rigetti/quilc -R

Diff for: README.md

@@ -15,7 +15,7 @@ Tequila can execute the underlying quantum expectation values on state of the ar
 
 # Installation
 Recommended Python version is 3.8-3.9.   
-Tequila supports linux, osx and windows. However, not all optional dependencies are supported on windows.
+Tequila supports linux, osx and windows. However, not all optional dependencies are supported on windows.  
 
 ## Install from PyPi
 **Do not** install like this: (Minecraft lovers excluded)

Diff for: requirements.txt

@@ -13,6 +13,7 @@ qulacs # default simulator (best integration), remove if the installation gives
 
 #optional quantum backends
 #cirq >= 0.9.2 #
+#cirq_google
 #qiskit>=0.30
 #pyquil<3.0 # you also need to install the forest-sdk
 #qulacs-gpu # you can't have qulacs and qulacs-gpu at the same time

Diff for: src/tequila/circuit/_gates_impl.py

@@ -6,7 +6,7 @@
 from tequila.objective.objective import Variable, FixedVariable, assign_variable
 from tequila.hamiltonian import PauliString, QubitHamiltonian, paulis
 from tequila.tools import list_assignment
-from numpy import pi, sqrt
+import numpy as np
 
 from dataclasses import dataclass
 
@@ -234,12 +234,12 @@ def shifted_gates(self, r=None):
         if r is None:
             r = self.eigenvalues_magnitude
 
-        s =  pi / (4 * r)
+        s =  np.pi / (4 * r)
         if self.is_controlled() and not self.assume_real:
             # following https://arxiv.org/abs/2104.05695
             shifts = [s, -s, 3 * s, -3 * s]
-            coeff1 = (sqrt(2) + 1)/sqrt(8) * r
-            coeff2 = (sqrt(2) - 1)/sqrt(8) * r
+            coeff1 = (np.sqrt(2) + 1)/np.sqrt(8) * r
+            coeff2 = (np.sqrt(2) - 1)/np.sqrt(8) * r
             coefficients = [coeff1, -coeff1, -coeff2, coeff2]
             circuits = []
             for i, shift in enumerate(shifts):
@@ -344,7 +344,7 @@ class PowerGateImpl(ParametrizedGateImpl):
 
     @property
     def power(self):
-        return self.parameter/pi
+        return self.parameter/np.pi
 
     def __init__(self, name, generator: QubitHamiltonian,  target: list, power, control: list = None):
         if generator is None:
@@ -353,7 +353,7 @@ def __init__(self, name, generator: QubitHamiltonian,  target: list, power, cont
         if name is None:
             assert generator is not None
             name = str(generator)
-        super().__init__(name=name, parameter=power * pi, target=target, control=control, generator=generator)
+        super().__init__(name=name, parameter=power * np.pi, target=target, control=control, generator=generator)
 
 
 class GeneralizedRotationImpl(DifferentiableGateImpl):
@@ -376,11 +376,44 @@ def extract_targets(generator):
             targets += [k for k in ps.keys()]
         return tuple(set(targets))
 
-    def __init__(self, angle, generator, control=None, eigenvalues_magnitude=0.5, steps=1, assume_real=False):
-        super().__init__(eigenvalues_magnitude=eigenvalues_magnitude, assume_real=assume_real, name="GenRot", parameter=angle, target=self.extract_targets(generator), control=control)
+    def __init__(self, angle, generator, p0=None, control=None, target=None, eigenvalues_magnitude=0.5, steps=1, name="GenRot", assume_real=False):
+        if target == None:
+            target = self.extract_targets(generator)
+        super().__init__(eigenvalues_magnitude=eigenvalues_magnitude, generator=generator, assume_real=assume_real, name=name, parameter=angle, target=target, control=control)
         self.steps = steps
-        self.generator = generator
+        if control is None and p0 is not None:
+            # augment p0 for control qubits
+            # Qp = 1/2(1+Z) = |0><0|
+            p0 = p0*paulis.Qp(control)
+        self.p0 = p0
+        
+    def shifted_gates(self):
+        if not self.assume_real:
+            # following https://arxiv.org/abs/2104.05695
+            s = 0.5 * np.pi
+            shifts = [s, -s, 3 * s, -3 * s]
+            coeff1 = 0.25 * (np.sqrt(2) + 1)/np.sqrt(2)
+            coeff2 = 0.25 * (np.sqrt(2) - 1)/np.sqrt(2)
+            coefficients = [coeff1, -coeff1, -coeff2, coeff2]
+            circuits = []
+            for i, shift in enumerate(shifts):
+                shifted_gate = copy.deepcopy(self)
+                shifted_gate.parameter += shift
+                circuits.append((coefficients[i], shifted_gate))
+            return circuits
 
+        r = 0.25
+        s = 0.5*np.pi
+        
+        Up1 = copy.deepcopy(self)
+        Up1._parameter = self.parameter+s
+        Up2 = GeneralizedRotationImpl(angle=s, generator=self.p0, eigenvalues_magnitude=r) # controls are in p0
+        Um1 = copy.deepcopy(self)
+        Um1._parameter = self.parameter-s
+        Um2 = GeneralizedRotationImpl(angle=-s, generator=self.p0, eigenvalues_magnitude=r) # controls are in p0
+
+        return [(2.0 * r, [Up1,  Up2]), (-2.0 * r, [Um1, Um2])]
+        
 class ExponentialPauliGateImpl(DifferentiableGateImpl):
     """
     Same convention as for rotation gates:

Diff for: src/tequila/circuit/gates.py

@@ -361,10 +361,13 @@ def Rp(paulistring: typing.Union[PauliString, str], angle, control: typing.Union
     return ExpPauli(paulistring=paulistring, angle=angle, control=control, *args, **kwargs)
 
 
+def GenRot(*args, **kwargs):
+    return GeneralizedRotation(*args, **kwargs)
+
 def GeneralizedRotation(angle: typing.Union[typing.List[typing.Hashable], typing.List[numbers.Real]],
                         generator: QubitHamiltonian,
                         control: typing.Union[list, int] = None,
-                        eigenvalues_magnitude: float = 0.5,
+                        eigenvalues_magnitude: float = 0.5, p0=None,
                         steps: int = 1, assume_real=False) -> QCircuit:
     """
 
@@ -393,6 +396,8 @@ def GeneralizedRotation(angle: typing.Union[typing.List[typing.Hashable], typing
         list of control qubits
     eigenvalues_magnitude
         magnitude of eigenvalues, in most papers referred to as "r" (default 0.5)
+    p0
+        possible nullspace projector (if the rotation is happens in Q = 1-P0). See arxiv:2011.05938
     steps
         possible Trotterization steps (default 1)
 
@@ -403,7 +408,7 @@ def GeneralizedRotation(angle: typing.Union[typing.List[typing.Hashable], typing
 
     return QCircuit.wrap_gate(
         impl.GeneralizedRotationImpl(angle=assign_variable(angle), generator=generator, control=control,
-                                eigenvalues_magnitude=eigenvalues_magnitude, steps=steps, assume_real=assume_real))
+                                eigenvalues_magnitude=eigenvalues_magnitude, steps=steps, assume_real=assume_real, p0=p0))
 
 
 
@@ -473,7 +478,7 @@ def Trotterized(generator: QubitHamiltonian = None,
     return QCircuit.wrap_gate(impl.TrotterizedGateImpl(generator=generator, angle=angle, steps=steps, control=control, randomize=randomize, **kwargs))
 
 
-def SWAP(first: int, second: int, control: typing.Union[int, list] = None, power: float = None, *args,
+def SWAP(first: int, second: int, angle: float = None, control: typing.Union[int, list] = None, power: float = None, *args,
          **kwargs) -> QCircuit:
     """
     Notes
@@ -486,10 +491,12 @@ def SWAP(first: int, second: int, control: typing.Union[int, list] = None, power
         target qubit
     second: int
         target qubit
+    angle: numeric type or hashable type
+        exponent in the for e^{-i a/2 G}
     control
         int or list of ints
     power
-        numeric type (fixed exponent) or hashable type (parametrized exponent)
+        numeric type (fixed exponent) or hashable type (parametrized exponent in the form (SWAP)^n
 
     Returns
     -------
@@ -498,12 +505,82 @@ def SWAP(first: int, second: int, control: typing.Union[int, list] = None, power
     """
 
     target = [first, second]
+    if angle is not None:
+        assert power is None
+        angle = assign_variable(angle)
+    elif power is not None:
+        angle = assign_variable(power)*np.pi
     generator = 0.5 * (paulis.X(target) + paulis.Y(target) + paulis.Z(target) - paulis.I(target))
-    if power is None or power in [1, 1.0]:
+    if angle is None or power in [1, 1.0]:
         return QGate(name="SWAP", target=target, control=control, generator=generator)
     else:
-        return GeneralizedRotation(angle=power * np.pi, control=control, generator=generator,
+        return GeneralizedRotation(angle=angle, control=control, generator=generator,
                                    eigenvalues_magnitude=0.25)
+        
+        
+def iSWAP(first: int, second: int, control: typing.Union[int, list] = None, power: float = 1.0, *args,
+         **kwargs) -> QCircuit:
+    """
+    Notes
+    ----------
+    iSWAP gate
+    .. math::
+        iSWAP = e^{i\\frac{\\pi}{4} (X \\otimes X + Y \\otimes Y )}
+
+    Parameters
+    ----------
+    first: int
+        target qubit
+    second: int
+        target qubit
+    control
+        int or list of ints
+    power
+        numeric type (fixed exponent) or hashable type (parametrized exponent)
+
+    Returns
+    -------
+    QCircuit
+
+    """
+
+    generator = paulis.from_string(f"X({first})X({second}) + Y({first})Y({second})")
+    
+    p0 = paulis.Projector("|00>") + paulis.Projector("|11>")
+    p0 = p0.map_qubits({0:first, 1:second})
+
+    gate = QubitExcitationImpl(angle=power*(-np.pi/2), target=generator.qubits, generator=generator, p0=p0, control=control, compile_options="vanilla", *args, **kwargs)
+    
+    return QCircuit.wrap_gate(gate)
+    
+    
+def Givens(first: int, second: int, control: typing.Union[int, list] = None, angle: float = None, *args,
+         **kwargs) -> QCircuit:
+    """
+    Notes
+    ----------
+    Givens gate G
+    .. math::
+        G = e^{-i\\theta \\frac{(Y \\otimes X - X \\otimes Y )}{2}}
+
+    Parameters
+    ----------
+    first: int
+        target qubit
+    second: int
+        target qubit
+    control
+        int or list of ints
+    angle
+        numeric type (fixed exponent) or hashable type (parametrized exponent), theta in the above formula
+
+    Returns
+    -------
+    QCircuit
+
+    """
+
+    return QubitExcitation(target=[second,first], angle=2*angle, control=control, *args, **kwargs)  # twice the angle since theta is not divided by two in the matrix exponential
 
 
 """
@@ -965,11 +1042,7 @@ def QGate(name, target: typing.Union[list, int], control: typing.Union[list, int
 returns a QCircuit of primitive tq gates
 """
 
-class QubitExcitationImpl(impl.DifferentiableGateImpl):
-
-    @property
-    def steps(self):
-        return 1
+class QubitExcitationImpl(impl.GeneralizedRotationImpl):
 
     def __init__(self, angle, target, generator=None, p0=None, assume_real=True, control=None, compile_options=None):
         angle = assign_variable(angle)
@@ -990,15 +1063,9 @@ def __init__(self, angle, target, generator=None, p0=None, assume_real=True, con
         else:
             assert generator is not None
             assert p0 is not None
-
-        super().__init__(name="QubitExcitation", parameter=angle, target=target, control=control)
-        self.generator = generator
-        if control is not None:
-            # augment p0 for control qubits
-            # Qp = 1/2(1+Z) = |0><0|
-            p0 = p0*paulis.Qp(control)
-        self.p0 = p0
-        self.assume_real = assume_real
+        
+        super().__init__(name="QubitExcitation", angle=angle, generator=generator, target=target, p0=p0, control=control, assume_real=assume_real, steps=1)
+        
         if compile_options is None:
             self.compile_options = "optimize"
         elif hasattr(compile_options, "lower"):
@@ -1007,18 +1074,9 @@ def __init__(self, angle, target, generator=None, p0=None, assume_real=True, con
             self.compile_options = compile_options
 
     def map_qubits(self, qubit_map: dict):
-        mapped_generator = self.generator.map_qubits(qubit_map=qubit_map)
-        mapped_p0 = self.p0.map_qubits(qubit_map=qubit_map)
-        mapped_control = self.control
-        if mapped_control is not None:
-            mapped_control=tuple([qubit_map[i] for i in self.control])
-        result = copy.deepcopy(self)
-        result.generator=mapped_generator
-        result.p0 = mapped_p0
-        result._target = tuple([qubit_map[x] for x in self.target])
-        result._control = mapped_control
-        result.finalize()
-        return result
+        mapped = super().map_qubits(qubit_map)
+        mapped.p0 = self.p0.map_qubits(qubit_map=qubit_map)
+        return mapped
 
     def compile(self, exponential_pauli=False, *args, **kwargs):
         # optimized compiling for single and double qubit excitaitons following arxiv:2005.14475
@@ -1040,35 +1098,6 @@ def compile(self, exponential_pauli=False, *args, **kwargs):
         else:
             return Trotterized(angle=self.parameter, generator=self.generator, steps=1)
 
-    def shifted_gates(self):
-        if not self.assume_real:
-            # following https://arxiv.org/abs/2104.05695
-            s = 0.5 * np.pi
-            shifts = [s, -s, 3 * s, -3 * s]
-            coeff1 = 0.25 * (np.sqrt(2) + 1)/np.sqrt(2)
-            coeff2 = 0.25 * (np.sqrt(2) - 1)/np.sqrt(2)
-            coefficients = [coeff1, -coeff1, -coeff2, coeff2]
-            circuits = []
-            for i, shift in enumerate(shifts):
-                shifted_gate = copy.deepcopy(self)
-                shifted_gate.parameter += shift
-                circuits.append((coefficients[i], shifted_gate))
-            return circuits
-
-        r = 0.25
-        s = 0.5*np.pi
-
-        Up1 = copy.deepcopy(self)
-        Up1._parameter = self.parameter+s
-        Up1 = QCircuit.wrap_gate(Up1)
-        Up2 = GeneralizedRotation(angle=s, generator=self.p0, eigenvalues_magnitude=r) # controls are in p0
-        Um1 = copy.deepcopy(self)
-        Um1._parameter = self.parameter-s
-        Um1 = QCircuit.wrap_gate(Um1)
-        Um2 = GeneralizedRotation(angle=-s, generator=self.p0, eigenvalues_magnitude=r) # controls are in p0
-
-        return [(2.0 * r, Up1 +  Up2), (-2.0 * r, Um1 + Um2)]
-
 def _convert_Paulistring(paulistring: typing.Union[PauliString, str, dict]) -> PauliString:
     '''
     Function that given a paulistring as PauliString structure or