Draft: Resolve "Use Numpy arrays instead of `ForEachObject` instances"

Closes #34 (closed)

lisainstrument/indexing.py

@@ -8,13 +8,10 @@ Authors:
 """
 
 import numpy as np
-import logging
 
-logger = logging.getLogger(__name__)
 
-
-"""List of MOSA index as two-figure strings, in the order they are used in an array."""
 MOSAS = ['12', '23', '31', '13', '32', '21']
+SC = ['1', '2', '3']
 
 
 def index2mosa(index):
@@ -55,10 +52,6 @@ MOSA32 = mosa2index('32')
 MOSA21 = mosa2index('21')
 
 
-"""List of SC indices as one-figure strings, in the order they are used in an array."""
-SC = ['1', '2', '3']
-
-
 def index2sc(index):
     """Return SC index associated with a given array index.
 
@@ -180,3 +173,64 @@ def mosa2sc(mosa):
     if str(mosa) not in MOSAS:
         raise ValueError(f"invalid MOSA index '{mosa}'")
     return str(mosa)[0]
+
+
+def sc2leftdistant(sc):
+    """Return index of left distant SC.
+
+    Args:
+        sc: SC index, as one-figure string or integer
+    """
+    if str(sc) not in SC:
+        raise ValueError(f"invalid SC index '{sc}'")
+    return rotate(sc, nrot=1)
+
+
+def sc2rightdistant(sc):
+    """Return index of right distant SC.
+
+    Args:
+        sc: SC index, as one-figure string or integer
+    """
+    if str(sc) not in SC:
+        raise ValueError(f"invalid SC index '{sc}'")
+    return rotate(sc, nrot=-1)
+
+
+def sc2leftmosa(sc):
+    """Return left MOSA index.
+
+    Args:
+        sc: SC index, as one-figure string or integer
+    """
+    if str(sc) not in SC:
+        raise ValueError(f"invalid SC index '{sc}'")
+    return f'{sc}{sc2leftdistant(sc)}'
+
+
+def sc2rightmosa(sc):
+    """Return right MOSA index.
+
+    Args:
+        sc: SC index, as one-figure string or integer
+    """
+    if str(sc) not in SC:
+        raise ValueError(f"invalid SC index '{sc}'")
+    return f'{sc}{sc2rightdistant(sc)}'
+
+
+def sc2bothmosas(x):
+    """Broadcast a SC array to a MOSA array.
+
+    We broadcast by assuming the same values for both MOSAs of each SC.
+
+    Args:
+        sc: SC array
+
+    Returns:
+        A MOSA array.
+    """
+    if not isinstance(x, np.ndarray) or x.shape[0] != 3:
+        raise TypeError("invalid SC array")
+    sc_mosas = [sc2index(mosa2sc(mosa)) for mosa in MOSAS]
+    return x[sc_mosas]