'rotating' matrix data around one point

Hi everyone,

I am having the following matrix:

   -0.0052   -0.0113   -0.0178   -0.0157   -0.0053    0.0033    0.0073    0.0080    0.0071
   -0.0032   -0.0152   -0.0433   -0.0370   -0.0014    0.0144    0.0173    0.0150    0.0114
    0.0062    0.0026   -0.1158   -0.0565    0.0423    0.0467    0.0380    0.0267    0.0173
    0.0205    0.0551    0.2696    0.3313    0.1654    0.1145    0.0758    0.0435    0.0237
    0.0268    0.0611    0.1415    0.2187    0.2313    0.2187    0.1415    0.0611    0.0268
    0.0237    0.0435    0.0758    0.1145    0.1654    0.3313    *0.2696*    0.0551    0.0205
    0.0173    0.0267    0.0380    0.0467    0.0423   -0.0565   *-0.1158*    0.0026    0.0062
    0.0114    0.0150    0.0173    0.0144   -0.0014   -0.0370   -0.0433   -0.0152   -0.0032
    0.0071    0.0080    0.0073    0.0033   -0.0053   -0.0157   -0.0178   -0.0113   -0.0052

Now I want the data to 'move' around one of the 'points' in the matrix, namely the one between the marked points (0.2696 and -0.01158). So I want to -0.0433 point to be in the place of the -0.0370 point and the -0.0370 point one the place of the -0.0565 point and so on. I have no idea how to do this. Hopefully one of you will know.

Thanks in advance

[Doubutsu]

I wanted to know this to solve a problem I had. But now the problem was solved on an other way, so I don't need to know this anymore. Thanks everyone for helping!

Answer 1

[Andrei Bobrov]

data = [  -0.0052000  -0.0113000  -0.0178000  -0.0157000  -0.0053000   0.0033000   0.0073000   0.0080000   0.0071000
  -0.0032000  -0.0152000  -0.0433000  -0.0370000  -0.0014000   0.0144000   0.0173000   0.0150000   0.0114000
   0.0062000   0.0026000  -0.1158000  -0.0565000   0.0423000   0.0467000   0.0380000   0.0267000   0.0173000
   0.0205000   0.0551000   0.2696000   0.3313000   0.1654000   0.1145000   0.0758000   0.0435000   0.0237000
   0.0268000   0.0611000   0.1415000   0.2187000   0.2313000   0.2187000   0.1415000   0.0611000   0.0268000
   0.0237000   0.0435000   0.0758000   0.1145000   0.1654000   0.3313000   0.2696000   0.0551000   0.0205000
   0.0173000   0.0267000   0.0380000   0.0467000   0.0423000  -0.0565000  -0.1158000   0.0026000   0.0062000
   0.0114000   0.0150000   0.0173000   0.0144000  -0.0014000  -0.0370000  -0.0433000  -0.0152000  -0.0032000
   0.0071000   0.0080000   0.0073000   0.0033000  -0.0053000  -0.0157000  -0.0178000  -0.0113000  -0.0052000];

s = size(data);
ii = [6 7]; % index rows
jj = [7 7]; % index of columns
z = zeros(s);
z(sub2ind(s,ii,jj)) = 1;
t = 0 + (bwdist(z,'ch') == 1);
boundaries = bwboundaries(t,8);
b = boundaries{1}(1:end-1,:);
b1 = b*[1; s(1)] - s(1);
out = data;
out(b1) = out(circshift(b1,1));

[Doubutsu]

thanks a lot.

It does what I wanted it to do, but how does it work? Could you please explain it to me, because I don't understand it at all (I am not that good with matlab).

Thanks in advance

Answer 2

[Jos (10584)]

You can use CIRCSHIFT to move the a point to the centre of the matrix, and then apply ROT90 to rotate it, and apply CIRCSHIFT again.

M1 = magic(5)
rotpos = [0 1] % position of rotation point
M2 = circshift(M1,-rotpos) 
M3 = rot90(M2) 
M4 = circshift(M3, rotpos)

I am not sure if this is what you're really after though ...

[Doubutsu]

thanks =), but I was looking for something else...