Need help in indexing

Hi all,

I want to index C by M matrixs as below but I have problem in convert row index into linear index code, I am Using MATLAB R2013a, can any one help me,Thank you in advance

close all
clear all
clc
F=random('exp',1,3,3,4);
C=F*100
M=bsxfun(@times,  C./cumsum(C,3) , reshape(1:4,1,1,[])   )
[vec,idx] = max(M,[],1);      % value and row index of max in each column.
 S = size(M);                 % size of input array.

idx = idx + S(1)*(0:S(2)-1); % convert row index into linear index !!!!!!!!!
 C(idx)                % use linear index to get elements of C.

This are the error message

Error using +

Matrix dimensions must agree.

Error in Untitled6 (line 10)

idx = idx + S(1)*(0:S(2)-1); % convert row index into linear index.

Answer 1

[Walter Roberson]

Your M is 4 dimensional . The idx output of max along the first dimension is going to be 4 dimensional . You are trying to add a row vector to it.

[Ashraf Sherif]

Thank you Walter Roberson but I couldn't do it.

[Walter Roberson]

baseidx = idx + repmat((0:size(M,2)-1) * size(M,1),1,1,size(idx,3)) + repmat(reshape((0:size(M,3)-1) * size(M,1)*size(M,2),1,1,[]),1,size(idx,2),1);
rowidx = baseidx + repmat(reshape((0:size(M,1)-1),[],1),1,size(M,2),size(M,3));

[Ashraf Sherif]

Thank you a lot Walter Roberson