Are you sure about your math? Given the ratio touch_area_width / total_width, you're saying that if the touch area is smaller than the total width, the scaling factor will be less than 1, and thus make the result even smaller yet. On my device, the ratio total_width/touch_area_width is the right value to use for c0. Similar comment for the height/c2 value.
If you're in there, you might mention that all values are normalized WRT 1.0 before being multiplied by this matrix. It's easier to see the point of c1 and c3's equations if you have that fact in mind. Also, for cases where the touchscreen area is a subset of the screen area, these coefficients need to be negative.
Google Docs calculator
This document is amazing, I created a google docs calculator to build the command for me. It really should not be this difficult to do this, but your instructions worked *perfectly* for me.
Here is the google doc of the calculator: https://docs.google.com/spreadsheets/d/13CNQjWfzpEkHM4ZdCcUWDTdQNaFqQ6TYTwatQsYcHcQ/edit?usp=sharing
the spreadsheet method is obsolete in most cases
As described on the Touchscreen page, now I can do this instead:
xinput --map-to-output $(xinput list --id-only "Advanced Silicon S.A CoolTouch(TM) System") DVI-0
This page is now showing only the hard way. As the header says, the two pages need merging. But the hard way is still relevant when xrandr cannot identify the separate screens because they've been merged into one large screen. —This unsigned comment is by Ecloud (talk) 17:12, 13 July 2016. Please sign your posts with ~~~~!