[R] rank of a matrix

[Uwe Ligges]

mingan wrote:

> 
> 
> how do I check the rank of a matrix ?
> 
> say
> 
> A=  1   0   0
>     0   1   0
> 
> then rank(A)=2
> 
> what is this function?


Well, calculating the rank is from the computational point of view a 
very hard problem.
See ?qr

Uwe Ligges


> thanks
> 
> 
>  I did try help.search("rank"), but all the returned help information 
> seem irrelevant to what I want.
> 
>  I would like to know how people search for help information like this.
> 
> 
> 
> 
> 
> 
> rank(base)              Sample Ranks
> SignRank(stats)         Distribution of the Wilcoxon Signed Rank
>                        Statistic
> Wilcoxon(stats)         Distribution of the Wilcoxon Rank Sum
>                        Statistic
> friedman.test(stats)    Friedman Rank Sum Test
> kruskal.test(stats)     Kruskal-Wallis Rank Sum Test
> pairwise.wilcox.test(stats)
>                        Pairwise Wilcoxon rank sum tests
> wilcox.test(stats)      Wilcoxon Rank Sum and Signed Rank Tests
> 
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