Error using + Matrix dimensions must agree.

this error appears to me every time!! please help!!

this is my code :

clear;
clf;

% DM = Data matrix (d x n)
% columns are data points
s=0.25;
S1= [1 2]' + s*randn(2,100);
S2= [2 3]' + s*randn(2,100);
S3= [3 2]' + s*randn(2,100);
DM= [S1 S2 S3];
DM=DM(:,randperm(size(DM,2)));

plot(DM(1,:),DM(2,:),'yo'); hold on;

% M = Membership row vector (n)
% entries are membership values

% C = Cluster centers vector (d x k)
% each column is a cluster center

% Select k
k = 2;
n = size(DM,2);
d = size(DM,1);

% Forgy initialization: Choose random k points as cluster centers
pVec=randperm(n);
C=DM(:,pVec(1:k));
plot(C(1,:),C(2,:),'rx'); 
input('Press ENTER');

while (1)

      err=0;
      % Update M
      for i=1:n
          VL = C - DM(:,i);
          [y,j]= min(diag(VL'*VL));
          M(i)= j;
          err= err + y;
      end
      disp(err);

      % Update C
      Cp=C;
      for i=1:k
          C(:,i)=mean(DM(:,M == i),2);
      end

      for i=1:k
          plot([Cp(1,i) C(1,i)],[Cp(2,i) C(2,i)],'r-');
      end
      plot(C(1,:),C(2,:),'rx'); 
      input('Press ENTER');
  end

Answer 1

[Walter Roberson]

"my intention is o add 1 to every element in the first row of the 2x100 array, and add 2 to every element in the second row"

S1  = bsxfun(@plus, [1 2].', s*randn(2,100));

The code you had, S1= [1 2]' + s*randn(2,100); is valid in R2016b or later but not in earlier MATLAB.

Answer 2

[Geoff Hayes]

Ibrahim - the error is with this line (and the ones that follow)

 S1= [1 2]' + s*randn(2,100);

s is a scalar and so

 s*randn(2,100)

is a 2x100 array of random numbers multiplied by that scalar. You are then trying to add a 2x1 array to the 2x100 array. What is your intention? To concatenate the two arrays so that you get a 2x101 array like

 S1 = [ [1 2]'  s*randn(2,100)];

or do you want to add 1 to every element in the first row of the 2x100 array, and add 2 to every element in the second row?

[Ibrahim Alkhalifah]

my intention is o add 1 to every element in the first row of the 2x100 array, and add 2 to every element in the second row

[Torsten]

S1 = randn(2,100);
S1 = [s*S1(1,:) + 1 ; s*S1(2,:) + 2];

Same for S2 and S3.

Best wishes

Torsten.

[Ibrahim Alkhalifah]

this error appeared!! :

Attempted to access S2(3,:); index out of bounds because size(S2)=[2,100].

[Torsten]

S1 = randn(2,100);
S1 = [s*S1(1,:) + 1 ; s*S1(2,:) + 2];

S2 = randn(2,100);
S2 = [s*S2(1,:) + 2 ; s*S2(2,:) + 3];

S3 = randn(2,100);
S3 = [s*S3(1,:) + 3 ; s*S3(2,:) + 2];

Best wishes

Torsten.

Answer 3

[mohamed mohsen]

function [motionVect, EScomputations] = motionEstES(imgP, imgI, mbSize, p)

[row ,col] = size(imgI);

vectors = zeros(2,row*col/mbSize^2);
costs = ones(2*p + 1, 2*p +1) * 65537;

[mohamed mohsen]

Error in motionEstES (line 17) [row ,col] = size(imgI);

[Walter Roberson]

You would get that error if you attempted to run that code by clicking on the green Run button instead of calling the code passing in appropriate parameters. It appears that the code expects that the second parameter will be a grayscale image (not an RGB image, and not the filename of an image.)

[mohamed mohsen]

sorry, sir, I didn't get it? what exactly I suppose to write in the code?

thanx for your time

[Walter Roberson]

im1 = imread('FirstFile.png');
im2 = imread('SecondFile.png');
gim1 = rgb2gray(im1);
gim2 = rgb2gray(im2);
mbSize = 16;
p = 5;
[motionvect, escomp] = motionEstES(gim1, gim2, mbSize, p);