I want to access an excel file with 500 by 2 matrix and check the connected nodes(bidirectional) in that matrix and the output will be a matrix with 1 represent connection otherwise 0.When I run this code,the error is"Maximum variable size exceeded"

clc;
A = csvread('twitnet');
numnode = max(A(:));
adj = zeros(numnode,numnode); 
fromlist = A(:,1);
tolist = A(:,2);
fromtoidx = sub2ind([numnode,numnode], fromlist, tolist);  
adj(fromtoidx) = 1;
tofromidx = sub2ind([numnode,numnode], tolist, fromlist);  
adj(tofromidx) = 1;

[Jan]

Where is the "book" file? Is the attached "twitnet.csv" file meant? Which line is "line 52"? Please post the complete error message.

[SUNANNA S S]

Thank you for your reply. Sorry sir, I meant the "twitnet" file. The line 52 in sub2ind function definition ie, Out of range subscript. When I type numnode = max(A(:));instead of line 2 in above code, I get another error on line 4 of above code adj = zeros(numnode,numnode); the error displayed is the matrix size exceeded. I need to find the connected nodes in the excel file in the form of an adjacency matrix, that's why I coded like this. Please help sir.

[Jan]

@SUNANNA S S: All we see is two columns of data. You want the operation "find the connected nodes". I'm nat familiar with this operation and cannot guess, which kind of output you exactly want. Could you please explain this in a short example, e.g. a [5x2] matrix with inputs and a manually created output?

[SUNANNA S S]

Sir, For eg: A group has six nodes, i.e., a, b, c, d, e, and f .The links of the nodes are ab, ac, ad, ae, ba, bc, bd, bf, be,cd, cf, da, dc, df, ea, ed, ef, and fe. The unique nodes of both followees and followers are a, b, c, d, e, and f . So, I want a 6 by 6 matrix x in which, a is connected to b, c, d, and e; therefore, x12 = x13 = x14 = x15 = 1. By contrast, a is not connected to a and f, therefore x11 = x16 = 0. All the other cells are assigned values using the same method. Thanks

[Guillaume]

See also i-am-a-beginner-in-matlab-so-could-anyone-please-help-me-to-create-an-adjacency-matrix-based-on-th which seems to be the same question as this.

Answer 1

[Jan]

The values in tolist and fromlist are larger than the length of the input numnode. The file has 1000 rows, but only the first 500 are populated. Then using e.g. the indices 1937235 and 2589158 must fail.

We cannot guess, what you want to achieve based on the failing code only. So please edit the question and add more details.

[SUNANNA S S]

Sir, I had tried to get a n by n adjacency matrix in which n denotes the unique number of nodes in the dataset. For eg: A group has six nodes, i.e., a, b, c, d, e, and f .The links of the nodes are ab, ac, ad, ae, ba, bc, bd, bf, be,cd, cf, da, dc, df, ea, ed, ef, and fe. The unique nodes of both followees and followers are a, b, c, d, e, and f . So, I want a 6 by 6 matrix x in which, a is connected to b, c, d, and e; therefore, x12 = x13 = x14 = x15 = 1. By contrast, a is not connected to a and f, therefore x11 = x16 = 0. All the other cells are assigned values using the same method. Thanks