functions in msort.i - m

    msort(x1, x2, x3, ...)  


returns an index list which sorts the array X1 into increasing  
order.  Where X1 values are equal, the list will sort X2 into  
increasing order.  Where both X1 and X2 are equal, X3 will be  
in increasing order, and so on.  Finally, where all of the keys  
are equal, the returned list will leave the order unchanged  
from the input keys.  
The Xi may be numbers or strings (e.g.- X1 could be an integer  
while X2 was a string, and X3 was a real).  The Xi must all be  
conformable, and each dimension of X1 must be as large as the  
corresponding dimension of any otehr Xi.  
Hence, msort(x) will return the same list as sort(x), except  
where the values of x are equal, in which case msort leaves  
the order unchanged, while sort non-deterministically permutes  
equal elements.  This feature may cost a factor of two in speed,  
so don't use it unless you really need it.  In general, msort  
will call sort up to twice per input argument.  
Interpreted function, defined at i/msort.i   line 10  

    msort_rank(x)  
    msort_rank(x, list)  


returns a list of longs the same size and shape as X, whose  
values are the "rank" of the corresponding element of X among  
all the elements of X -- the smallest element has rank 0 and  
the largest has the largest rank, which is equal to one less  
than the number of distinct values in the array X.  
If LIST is present, it is set to the order list returned by  
sort(x(*)).  
Interpreted function, defined at i/msort.i   line 55