adds constant matrix operator

Author: julian-urban

fredipy/operators.py

@@ -2,6 +2,7 @@
 from typing import TYPE_CHECKING, Callable
 if TYPE_CHECKING:
     from .integrators import Integrator
+import numpy as np
 
 
 class Operator:
@@ -20,12 +21,22 @@ class Identity(Operator):
     pass
 
 
+class ConstMatrix(Operator):
+    def __init__(
+            self,
+            mat: np.ndarray):
+        self.mat = mat
+
+    def make(self, *args):
+        return self.mat
+
+             
 class Integral(Operator):
     '''Wrapper for integration constraints.
 
     Parameters
     ----------
-    func        : kernel function of the integrations.
+    func        : kernel function of the integrations
     integrator  : defines the integration routine, see Integrator class.
     '''
     def __init__(