change filt variable from global to local (#399)

* change filt variable from global to local

* fix single_opt method

* update changelog

---------

Co-authored-by: Michael Deceglie <[email protected]>

Author: martin-springer

docs/sphinx/source/changelog.rst

@@ -1,5 +1,6 @@
 RdTools Change Log
 ==================
+.. include:: changelog/v2.1.8.rst
 .. include:: changelog/v2.1.7.rst
 .. include:: changelog/v2.1.6.rst
 .. include:: changelog/v2.1.5.rst

docs/sphinx/source/changelog/v2.1.8.rst

@@ -0,0 +1,11 @@
+**************************
+v2.1.8 (November 17, 2023)
+**************************
+
+Bug fixes
+---------
+* Fix a bug in parallel computing environments (:issue:`388` :pull:`399`)
+
+Contributors
+------------
+* Martin Springer (:ghuser:`martin-springer`)

rdtools/normalization.py

@@ -380,7 +380,7 @@ def irradiance_rescale(irrad, irrad_sim, max_iterations=100,
     '''
 
     if method == 'iterative':
-        def _rmse(fact):
+        def _rmse(fact, filt):
             """
             Calculates RMSE with a given rescale fact(or) according to global
             filt(er)
@@ -392,10 +392,9 @@ def _rmse(fact):
 
         def _single_rescale(irrad, irrad_sim, guess):
             "Optimizes rescale factor once"
-            global filt
             csi = irrad / (guess * irrad_sim)  # clear sky index
             filt = (csi >= 0.8) & (csi <= 1.2) & (irrad > 200)
-            min_result = minimize(_rmse, guess, method='Nelder-Mead')
+            min_result = minimize(_rmse, guess, (filt), method='Nelder-Mead')
 
             factor = min_result['x'][0]
             return factor