Why does this loop for wave assignments not work?

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I have been stumped. Something that should be dirt simple is not working. This code bombs on the second loop with a wave assignment error "Attempt to operate on .. null (missing) wave". Yet I can run each list item separately and it works.

I have perhaps a mild flu and maybe my head is just not right from it. But ... what am I missing here?


Function CreatePseudoLangmuir()

	// data folders
	
	DFREF rd = root:rawdata
	DFREF an = root:analysis
	
	// local variables with file names
	
	string rdList = "T25;T40;T50;"
	string anList = "msvC23;msvC40;mvsC50;"
	string therd, thean
	
	variable ic, nt = 3
	
	// process the files
	
	for (ic=0;ic<nt;ic+=1)
	
		therd = StringFromList(ic,rdList)
		thean = StringFromList(ic,anList)
		
		WAVE/SDFR=rd wrd = $therd
		WAVE/SDFR=an wan = $thean
		
		// equilibrium amount absorbed per amount of resin
		wan[][0] =  (wrd[p][1] - wrd[p][2])/ wrd[p][0]
		// equilibrium concentration
		wan[][1] = wrd[p][2]
			
	endfor
	
	return 0

end
The following does not generate an error so... 


Function test()
 
	// data folders
 	newDataFolder/o/s rawdata
 	make/o/n=(4,6) T25,T40,T50
 	
 	SetDataFolder root:
 	newDataFolder/o/s analysis
 	Make/o/n=(4,6) msvC23,msvC40,mvsC50
  	SetDataFolder root:
	
	DFREF rd = root:rawdata
	DFREF an = root:analysis
 
	// local variables with file names
 
	string rdList = "T25;T40;T50;"
	string anList = "msvC23;msvC40;mvsC50;"
	string therd, thean
 
	variable ic, nt = 3
 
	// process the files
 
	for (ic=0;ic<nt;ic+=1)
 
		therd = StringFromList(ic,rdList)
		thean = StringFromList(ic,anList)
 
		WAVE/SDFR=rd wrd = $therd
		WAVE/SDFR=an wan = $thean
 
		// equilibrium amount absorbed per amount of resin
		wan[][0] =  (wrd[p][1] - wrd[p][2])/ wrd[p][0]
		// equilibrium concentration
		wan[][1] = wrd[p][2]
 
	endfor
 
	return 0
 
end

February 3, 2015 at 05:03 pm - Permalink
Turn debugging and WAVE checking on. When Igor breaks, check the value of therd and thean and the associated wave reference variables.

February 3, 2015 at 05:09 pm - Permalink
My guess at a very simple error is that the third analysis wave should be msvC50 not mvsC50. A.G. can run the code if the waves are created with those names, but what about the real example?

February 3, 2015 at 10:30 pm - Permalink
I found the mistake. As noted, the existing wave names were mvsC not msvC. Amazing what a good night's sleep can do to clear a fuzzy head cold.

--
J. J. Weimer
Chemistry / Chemical & Materials Engineering, UAHuntsville

February 4, 2015 at 06:06 am - Permalink