address zero weights for MIDAS data

Author: briantoby

GSASII/GSASIIpwd.py

@@ -2750,6 +2750,10 @@ def errPeakProfile(values,xdata,ydata,fixback,weights,dataType,parmdict,varylist
             print('Instrumental profile terms cannot be varied '+
                                     'in Laue Fringe fits:',warn)
 
+    if sum(w[xBeg:xFin]) == 0:
+        print('Unusable data: data weights are zero')
+        if dlg: dlg.Destroy()
+        return
     while not noFit:
         begin = time.time()
         values =  np.array(Dict2Values(parmDict, varyList))
@@ -2765,6 +2769,7 @@ def errPeakProfile(values,xdata,ydata,fixback,weights,dataType,parmdict,varylist
                 print (traceback.format_exc())
             else:
                 print('peak fit failure')
+            if dlg: dlg.Destroy()
             return
         ncyc = int(result[2]['nfev']/2)
         runtime = time.time()-begin

GSASII/GSASIIpwdGUI.py

@@ -2099,6 +2099,7 @@ def OnBackFit(event):
         back = wx.ComboBox(parent=G2frame.dataWindow,value=data[1]['background PWDR'][0],choices=Choices,
             style=wx.CB_READONLY|wx.CB_DROPDOWN)
         back.Bind(wx.EVT_COMBOBOX,OnBackPWDR)
+        back.SetMaxSize((450,-1))
         backSizer.Add(back)
         backSizer.Add(wx.StaticText(G2frame.dataWindow,-1,' multiplier'),0,WACV)
         backMult = G2G.ValidatedTxtCtrl(G2frame.dataWindow,data[1]['background PWDR'],1,nDig=(10,3),OnLeave=AfterChange)

GSASII/imports/G2pwd_MIDAS.py

@@ -65,7 +65,8 @@ async def zarrAsyncOpen(filename):
                     store = await zarr.storage.ZipStore.open(filename, mode="r")
                     fp = zarr.open_group(store, mode='r')
                     return fp,store
-                except FileNotFoundError as msg:
+#                except FileNotFoundError as msg:
+                except FileNotFoundError:
                     print (f'cannot read as zarr file: {filename}')
                 except Exception as msg:
                     self.errors = f'Exception from zarr module (version={zarr.__version__}):'
@@ -80,8 +81,8 @@ def ContentsValidator(self, filename):
         '''
         fp, store = self.zarrOpen(filename)
         if not fp:
-            self.errors = f'Exception from zarr module (version={zarr.__version__}):'
-            self.errors += '\n\t' + str(msg)
+            self.errors = f'Error from zarr module (version={zarr.__version__}):'
+            #self.errors += '\n\t' + str(msg)
             self.errors += '\nPlease report this'
         elif all([(i in fp) for i in self.midassections]): # are expected MIDAS sections present?
             self.mode = 'midas'
@@ -228,8 +229,8 @@ def readMidas(self, filename, fpbuffer={}):
         #   Y(GSAS) = Y-norm / nFrame
         #   sigma(Y-GSAS) = sigma(Y-norm) / nFrame
         #                 = sqrt( Y-norm / area) / nFrame
-        #   weight(Y-GSAS) is 1/sigma[Y-GSAS]**2 = nFrame**2 * area / Y-norm
-        w = np.where(y > 0, np.zeros_like(y), nFrame**2 * normalization/ y )
+        #   weight(Y-GSAS) is 1/sigma[Y-GSAS]**2 = nFrame**2 * area / Y(norm)
+        w = np.where(y <= 0, np.zeros_like(y), nFrame**2 * normalization/ y )
         omega = 999.  # indicates an error
         try:
             omega = 0.5 * (