Speed-up length property lookup for Pulse and PulseBlock.

For Pulse, we make it one of the named properties in the namedtuple. For
PulseBlock, we compute it on construction, and update it whenever we tensor on
another Pulse.

QGL/PulseSequencer.py

@@ -30,7 +30,7 @@
 
 from collections import namedtuple
 
-class Pulse(namedtuple("Pulse", ["label", "channel", "amp", "phase", "frequency",
+class Pulse(namedtuple("Pulse", ["label", "channel", "length", "amp", "phase", "frequency",
                                  "frameChange", "shapeParams", "isTimeAmp",
                                  "isZero", "ignoredStrParams"])):
     __slots__ = ()
@@ -46,7 +46,7 @@ def __new__(cls, label, channel, shapeParams, amp=1.0, phase=0, frameChange=0, i
                 raise NameError("shapeParams must include {0}".format(param))
         isTimeAmp = (shapeParams['shapeFun'] == PulseShapes.constant)
         isZero = (amp == 0)
-        return super(cls, Pulse).__new__(cls, label, channel, amp, phase, frequency, frameChange, shapeParams, isTimeAmp, isZero, ignoredStrParams)
+        return super(cls, Pulse).__new__(cls, label, channel, shapeParams['length'], amp, phase, frequency, frameChange, shapeParams, isTimeAmp, isZero, ignoredStrParams)
 
     def __str__(self):
         kwvals = []
@@ -69,18 +69,6 @@ def __str__(self):
     def _repr_pretty_(self, p, cycle):
         p.text(str(self))
 
-    @property
-    def length(self):
-        """Alias the shape parameter "length" """
-        return self.shapeParams["length"]
-
-    def __mul__(self, other):
-        """ Overload multiplication of Pulses as a "tensor" operator"""
-        if isinstance(other, Pulse):
-            return PulseBlock(self) * PulseBlock(other)
-        else:
-            return PulseBlock(self) * other
-
     def hashshape(self):
         return hash(frozenset(self.shapeParams.items()))
 
@@ -96,6 +84,7 @@ def __neg__(self):
                      -self.amp, self.phase, -self.frameChange)
 
     def __mul__(self, other):
+        """ Overload multiplication of Pulses as a "tensor" operator"""
         return self.promote() * other.promote()
 
     def promote(self):
@@ -182,10 +171,10 @@ class PulseBlock(object):
     '''
 
     def __init__(self, *pulses):
-        #Set some default values
-        #How multiple channels are aligned.
         self.alignment = 'left'
         self.pulses = OrderedDict([(pulse.channel, pulse) for pulse in pulses])
+        # The maximum length for any channel on this block
+        self.length = max(p.length for p in self.pulses.values())
         self.label = None
 
     def __repr__(self):
@@ -203,7 +192,7 @@ def _repr_pretty_(self, p, cycle):
         p.text(labelPart + "⊗ ".join([str(pulse)
                                       for pulse in self.pulses.values()]))
 
-    #Overload the multiplication operator to combine pulse blocks
+    # Overload the multiplication operator to combine pulse blocks
     def __mul__(self, rhs):
         # make sure RHS is a PulseBlock
         rhs = rhs.promote()
@@ -217,6 +206,7 @@ def __mul__(self, rhs):
                     "Attempted to multiply pulses acting on the same space")
             else:
                 result.pulses[k] = v
+        result.length = max(self.length, rhs.length)
         return result
 
     def __eq__(self, other):
@@ -232,20 +222,14 @@ def __eq__(self, other):
     def __ne__(self, other):
         return not self == other
 
-    #PulseBlocks don't need to be promoted, so just return self
+    # PulseBlocks don't need to be promoted, so just return self
     def promote(self):
         return self
 
     @property
     def channel(self):
         return self.pulses.keys()
 
-    #The maximum length for any channel on this block
-    @property
-    def length(self):
-        return max(p.length for p in self.pulses.values())
-
-
 def align(pulseBlock, mode="center"):
     # make sure we have a PulseBlock
     pulseBlock = pulseBlock.promote()