1 ACCEPTED SOLUTION
Accepted Solutions
The reason for this effect is because Mathcads various lookup and match routines use the system variable TOL to decide if a value is found. This means it might not be an exact match (thats another difference between Andy's Match and the builtin match).
In your sheet TOL is set to 10^-2 (which is rather low but I guess there might be a reason for this). With this setting lookup will find 10 values in L_1 and L_2 which are around the searched for max within this tolerance and returns the corresponding values in X.Holes. In fact there are only 5 values, but each one is found twice as the columns L_1 and L_2 are identical.
As you had decided you are interested in the first one only, you get it and it is 20.290.
Setting TOL to the default 10^-3 or lower cures the problem and only two matches are found (which is OK as we have the max value in the first and in the second column present (and fortunately in the same row.
So one way to get what you want is to set TOL lower before using lookup and back to the desired value afterwards
or use Andys routine (maybe modified so it return the desired value directly) or use the more versatile routine which I provided at the end of the sheet I posted.
Andy's Match-routine is pretty much the same as the built-in match command.
You could replace
by
Both return the index of the found value. The only difference is when the value is not found. Andy returns -1 and the buitl-in routine would throw an error. But even if you use Andys routine and Freds revision you will get an error if the value is not present in one of the columns (as of -1 is not a valid index).
In any case your problem with this approach is, as I understand it, that your maximum may only be present in one of the two columns or it may be present in both but at different rows. I understood that your goal is to search for the max value in both columns at the same time.
BTW, what on heaven earth is so hard to provide a sheet with dummy data to demonstrate the needs? We already had people just posting pics to be debuged but Mathcad sheets which just contains pics is new to me.
The reason for this effect is because Mathcads various lookup and match routines use the system variable TOL to decide if a value is found. This means it might not be an exact match (thats another difference between Andy's Match and the builtin match).
In your sheet TOL is set to 10^-2 (which is rather low but I guess there might be a reason for this). With this setting lookup will find 10 values in L_1 and L_2 which are around the searched for max within this tolerance and returns the corresponding values in X.Holes. In fact there are only 5 values, but each one is found twice as the columns L_1 and L_2 are identical.
As you had decided you are interested in the first one only, you get it and it is 20.290.
Setting TOL to the default 10^-3 or lower cures the problem and only two matches are found (which is OK as we have the max value in the first and in the second column present (and fortunately in the same row.
So one way to get what you want is to set TOL lower before using lookup and back to the desired value afterwards
or use Andys routine (maybe modified so it return the desired value directly) or use the more versatile routine which I provided at the end of the sheet I posted.
