Index: /issm/trunk-jpl/src/m/boundaryconditions/love_numbers.py
===================================================================
--- /issm/trunk-jpl/src/m/boundaryconditions/love_numbers.py	(revision 22358)
+++ /issm/trunk-jpl/src/m/boundaryconditions/love_numbers.py	(revision 22359)
@@ -17,6 +17,19 @@
 # 
 
+        # some checks:
+        if len(varargin)==0:
+        	frame='CM';
+		print 'Info: computation is done in Center of Mass (CM) reference frame by default'
+        elif len(varargin)==1: 
+		reference_frame = varargin[0]
+		if (reference_frame in ['CF','CM']):
+	            	frame=reference_frame;
+		else:
+			raise RuntimeError('reference_frame should be one of ''CM'' or ''CF''')
+        else:
+            	raise RuntimeError('love_numbers error message: bad usage') 
+        
         if value not in ['h','k','l','gamma','lambda']:
-            raise RuntimeError('value should be one of ''h'',''k'',''l'',''gamma'' and ''lambda''') 
+        	raise RuntimeError('value should be one of ''h'',''k'',''l'',''gamma'' and ''lambda''') 
         
         if len(varargin)>1: 
@@ -10039,11 +10052,10 @@
 	
 	# choose degree 1 term for CF reference system 
-        for frame in varargin:
-            if frame=='CF': # from Blewitt, 2003, JGR 
-                if value=='h':
+        if frame=='CF': # from Blewitt, 2003, JGR 
+            if value=='h':
                     series[1] = -0.269; 
-                elif value=='k':
+            elif value=='k':
                     series[1] = 0.021;  
-                elif value=='l':
+            elif value=='l':
                     series[1] = 0.134;