Hello!
Sorry for my english
I just found this "problem"
I think that first "mas" was sorted by first column. But "Mathcad 14" doesn't think so... And we get "mas1"... But again "Mathcad" doesn't think that "mas1" is sorted... and so on...
This little thing brought me a lot of problems...
Can you tell me, is it error of "Mathcad 14"? Or it works as it should? And what should I do?..
Thank!
Sergey
ACCEPTED SOLUTION
Accepted Solutions
It is not a bug. When you sort by column 0 there are multiple solutions that are equally valid. The starting point is one valid solution, and the ending point is another. This may be considered undesirable behavior, but it's not a bug.
Tom wrote a Csort function that allows you to sort by multiple columns (csort does not preserve the order of previous sorts), but that also does not attempt to preserve the order of columns that are not specified for the sorting. So I modified it (in my opinion, the new version is an improvement over Tom's version, but then I wrote the modification, so I am biased 
).
Edit: 11:50 AM Dec 31. I just uploaded a new file with a minor modificaton to the new function.
A word of caution. The routine by Tom, as well as the improvement by Richard, fail if the matrix is large enough and you want to sort successively by enough columns. Demonstration:
Phew, it does.
But When I increase lc to 4 (add an extra column to the matrix):
The maximum difference is 8, not 0.
Row 8130 should follow, not precede rows 8131 and 8132.
QED
Luc
Of course there's a solution. If you are willing to take a little more processing time you can get:
With 10 million matrix elements, no problem sorting on 10 columns.
The routine is recursive:
Success!
Luc
Bearing in mind, of course, that nothing gets implemented until it has been suggested by at least ten people, ten times each, over a period of at least ten years, we should all get out our black paper and invisible ink and start writing!
The usual way is to write your message using invisible ink...
I know 7 examples when the invisible variable/function/operator name is useful.
Do you know more?
Example 1. Invisible addition
Mathcad allow us to change the multiplication sign. A user may select the one from the following:
2×а 2·а 2 х a 2 а 2а
The multiplication sign is invisible in last two examples that conform to the tradition existing in mathematics do not place a sing between efficients, if the first is a constant and the second is a variable.
Comment
For that reason, a variable name cannot start with digits.
However, blank space between the two values may mean as addition, as multiplication. For example, 2 hours 30 minutes, 1 kilometer 200 metes etc. Here the invisible addition sign stands between the same quantities (time and length), and multiplication sign — between the constants and the units. Fig. 1 shows how to solve it in Mathcad.
Example 2. Zero dimension quantity
Sometimes Mathcad is too pedantic in dimensional quantities. For example, one says that some equipment is situated at a height of twenty meters and another at zero and not specifies the units of that zero (meters, centimeters, feet, or inches etc). Nevertheless, Mathcad always displays the units of the dimensional values even when it is not necessary. In that case, we can hide an excess unit converting it to invisible (Fig. 2).
Example 3. The Roman arithmetic
Mathcad works with decimal, binary, hexadecimal, octal numbers. However, we may need to make Mathcad work with forms more exotic, for example, with Roman numbers. For that, we insert the function with the invisible name that returns a Roman number if its argument is an Arabic and conversely the Arabic number if the argument is Roman (Fig. 3).
Example 4. The sparse matrix
Mathcad has powerful instruments to work with vectors and matrixes (arrays). There is one limitation: these arrays should be completely filled. In practice we sometimes deal with nonrectangular matrixes, for example, with triangular. The matrixes may have more complicated form. Fig. 4 shows how to imitate working with sparse matrix.
Example 5. Invisible matker on the plot:
Example 6. Duoble answer with two units:
Example 7. Endless loop:
Some tasks can't be solved with csort and rsort as they are today..
That is true. So unless you have a great deal of patience and are prepared to wait until the alternative functions are implemented (or the heat death of the universe occurs, which may be sooner), use the functions I posted 
I expect a lot of people would have complained if it couldn't!
Complained!!!!!!!!
WE DON'T COMPLANE ON HERE DO WE ?????? 
Mike
