Interface simplifications

A series of interface improvements

BREAKS THE CURRENT INTERFACE, but I think the improvements/simplifications are worth it:

• new load_budget() convenience function returns only Budget class, with ifo pre-set as class attribute.
• clean ups to gwinc() convenience function
• add Budget.run() method as simple interface to run all usual methods for common use case.

gwinc/ifo/noises.py

@@ -50,20 +50,20 @@ def ifo_power(ifo, PRfixed=True):
     """Compute power on beamsplitter, finesse, and power recycling factor.
 
     """
-    c       = const.c
-    pin     = ifo.Laser.Power
-    t1      = sqrt(ifo.Optics.ITM.Transmittance)
-    r1      = sqrt(1 - ifo.Optics.ITM.Transmittance)
-    r2      = sqrt(1 - ifo.Optics.ETM.Transmittance)
-    t5      = sqrt(ifo.Optics.PRM.Transmittance)
-    r5      = sqrt(1 - ifo.Optics.PRM.Transmittance)
-    loss    = ifo.Optics.Loss                          # single TM loss
-    bsloss  = ifo.Optics.BSLoss
-    acoat   = ifo.Optics.ITM.CoatingAbsorption
-    pcrit   = ifo.Optics.pcrit
+    c = const.c
+    pin = ifo.Laser.Power
+    t1 = sqrt(ifo.Optics.ITM.Transmittance)
+    r1 = sqrt(1 - ifo.Optics.ITM.Transmittance)
+    r2 = sqrt(1 - ifo.Optics.ETM.Transmittance)
+    t5 = sqrt(ifo.Optics.PRM.Transmittance)
+    r5 = sqrt(1 - ifo.Optics.PRM.Transmittance)
+    loss = ifo.Optics.Loss  # single TM loss
+    bsloss = ifo.Optics.BSLoss
+    acoat = ifo.Optics.ITM.CoatingAbsorption
+    pcrit = ifo.Optics.pcrit
 
     # Finesse, effective number of bounces in cavity, power recycling factor
-    finesse = 2*pi / (t1**2 + 2*loss)        # arm cavity finesse
+    finesse = 2*pi / (t1**2 + 2*loss)  # arm cavity finesse
     neff    = 2 * finesse / pi
 
     # Arm cavity reflectivity with finite loss
@@ -73,17 +73,17 @@ def ifo_power(ifo, PRfixed=True):
     if PRfixed:
         Tpr = ifo.Optics.PRM.Transmittance  # use given value
     else:
-        Tpr = 1-(rarm*sqrt(1-bsloss))**2 # optimal recycling mirror transmission
+        Tpr = 1-(rarm*sqrt(1-bsloss))**2  # optimal recycling mirror transmission
         t5 = sqrt(Tpr)
         r5 = sqrt(1 - Tpr)
     prfactor = t5**2 / (1 + r5 * rarm * sqrt(1-bsloss))**2
 
-    pbs  = pin * prfactor          # BS power from input power
-    parm = pbs * garm**2 / 2       # arm power from BS power
+    pbs  = pin * prfactor  # BS power from input power
+    parm = pbs * garm**2 / 2  # arm power from BS power
 
     thickness = ifo.Optics.ITM.get('Thickness', ifo.Materials.MassThickness)
     asub = 1.3 * 2 * thickness * ifo.Optics.SubstrateAbsorption
-    pbsl = 2 *pcrit / (asub+acoat*neff) # bs power limited by thermal lensing
+    pbsl = 2 *pcrit / (asub+acoat*neff)  # bs power limited by thermal lensing
 
     if pbs > pbsl:
         logging.warning('P_BS exceeds BS Thermal limit!')