Hello, I'm new here and I'm trying to figure out how to use MATLAB to crunch some numbers about neutron counts. I have data from a detctor and ultimately I'd like to linearize it! I'm using wtls_line found at: http://www.mathworks.com/matlabcentral/fileexchange/17466-weighted-total-least-squares-straight-line-fit/content/wtls_line.m OK so when I go to extract the data--attached, I use a column, from a file of type .m, which is a double (and I believe is the cause of the problem). Upon trying to use wtls_line, I define xin, yin, uxin, yxin, and guck, (all are necessary to work properly, correct?) Then I type: [a,b,alpha,p,chiopt,Cab,Calphap]= wtls_line(xin,yin,uxin,uyin,guck) which returns Undefined function 'wtls_line' for input arguments of type 'double'. It may be that I don't know how to properly call upon a function but I think I either need to change the data I'm extracting from double to something else or the problem is something that I don't know. Does anyone have any clue how to solve this issue? Also, I plan on plotting this information against the same data type (neutron counts) but for other detectors... (may be irrelevant) I appreciate any help you can offer! Thank you. -Michael Figured it out: the file name didn't match the function name. I did a 'save as...' and changed the name. Sorry.