Speed up spectral fit; take into account that in seldom cases not all

pick information in pick dictionary are available.

pylot/core/analysis/magnitude.py

@@ -751,13 +751,16 @@ def fitSourceModel(f, S, fc0, iplot, verbosity=False):
     # check difference of il and ir in order to
     # keep calculation time acceptable
     idiff = ir - il
-    if idiff > 10000:
+    print(idiff)
+    if idiff > 100000:
+        increment = 1000
+    elif idiff <= 100000 and idiff > 10000:
         increment = 100
     elif idiff <= 20:
         increment = 1
     else:
         increment = 10
-
+    print(increment)
     for i in range(il, ir, increment):
         FC = f[i]
         indexdc = np.where((f > 0) & (f <= FC))