As python evaluates expressions from the left to the right, put the vector in...

As python evaluates expressions from the left to the right, put the vector in the rightmost position so that we do not multiply it with a scalar several times.

pcigale/sed/__init__.py

@@ -326,7 +326,7 @@ class SED(object):
 
         # Return Fν in mJy. The 1e-9 factor is because λ is in nm and 1e29 for
         # convert from W/m²/Hz to mJy.
-        return lambda_eff * lambda_eff * f_lambda * 1e-9 / c * 1e29
+        return 1e-9 / c * 1e29 * lambda_eff * lambda_eff * f_lambda
 
     def to_votable(self, filename, mass=1.):
         """