Re: sort and positon matrix element help
- To: mathgroup at smc.vnet.net
- Subject: [mg73091] Re: sort and positon matrix element help
- From: dh <dh at metrohm.ch>
- Date: Thu, 1 Feb 2007 04:36:07 -0500 (EST)
- References: <epp6nn$dcl$1@smc.vnet.net>
Hi,
If I understand correctly, you want to sort the elements of a matrix and
retaining the row/col info.m Assume the matrix is: m: We first create an
index matrix:
ind = Table[{i, j}, {i, Length[m]}, {j, Length[m[[1]]]}]
then we "join" both matrices and flatten it to a list with elements
{number,{row,col}}:
t = MapThread[{#1, #2} &, {m, ind}, 2]
t = Flatten[t, 1]
Now we sort according to the first element of {number,{row,col}} :
Sort[t, #1[[1]] < #2[[1]] &]
Daniel
comp.soft-sys.math.mathematica wrote:
> Hi, guys,
>
> I am attacking one proble and may need your help.
> I have a large matrix(m*n). I wanna to sort out the matrix
> from large to small according to its element's value AND save the
> corresponding row and column number as its position. Latter on, plot
> out the first 20 largest value accroding to their positions.
> Is there any good way to do this, especially take out the
> positons of element and assocate it with the value?
>