Merge branch 'cm/krauss_ops' of github.com:pasqal-io/horqrux into cm/…

…krauss_ops

horqrux/primitive.py

@@ -106,7 +106,9 @@ def I(
 def X(
     target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
-    """X gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
+    """The definition for the X gate.
+    
+    This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
 
     Example usage: X(1) represents the instruction to apply X to qubit 1.

horqrux/shots.py

@@ -49,7 +49,7 @@ def eigen_probabilities(state: Any, eigvecs: Array) -> Array:
     Returns:
         Array: The probabilities.
     """
-    raise NotImplementedError("prod_eigenvectors_state is not implemented")
+    raise NotImplementedError(f"prod_eigenvectors_state is not implemented for the state type {type(state)}.")
 
 
 @eigen_probabilities.register

horqrux/utils_noise.py

@@ -119,7 +119,7 @@ def PauliChannel(error_probability: tuple[float, ...]) -> tuple[Array, ...]:
         raise ValueError("The sum of probabilities can't be greater than 1.0")
     for probability in error_probability:
         if (probability > 1.0) or (probability < 0.0):
-            raise ValueError("The probability values are not correct probabilities")
+            raise ValueError(f"The error probability values are incorrect. Got {probability}.")
     px, py, pz = (
         error_probability[0],
         error_probability[1],