Matrix Creation Code Problem

Hello.

I've a matrix 61312*3.

1st column: from 1 to 81 (Originating Place)

2nd column: from 1 to 81 (Destination place of a vehicle)

3rd column: from 1 to 246 (where the vehicle has surveyed)

There are 61312 observation (no. of rows) at 246 locations.

I need to create a matrix, which shows that from origin (1 to 81) to Destination (1 to 81), which of the location (1 to 246) these vehicle follows. I think the order of the matrix will be 81*81, but there can be more than one value in a cell because of many surveyed location.

With the help of this forum, I've done below coding.

A=combinedfile;

[a,~,ii] = unique(A(:,1));

[b,~,jj] = unique(A(:,2));

out1 = accumarray([ii,jj],A(:,3),[max(ii), max(jj)],@(x){x});

out = [[{nan};num2cell(a(:))],[num2cell(b(:)');out1]];

I get the matrix at the end, but the problems are some cells contains brackets while some contain vaules*1 double (i.e. 440*1 double).

Kindly let me know how should I get rid of these problems. Thanks in advance.

Answer 1

[Andrei Bobrov]

use

[a,~,ii] = unique(A(:,1));
[b,~,jj] = unique(A(:,2));
f = @(x)x(1); % or f = @(x)x(end); or f = @(x)x(randperm(numel(x),1)); 
out1 = accumarray([ii,jj],A(:,3),[max(ii), max(jj)],f);
out = [nan,b(:)';a(:),out1];

[Fayyaz]

Hi Andrei, thanks for this.

Now the other problems solved, but this time I get only one value in the cell in the matrix, but there can be more than one values in the cell, because the vehicles can go through many locations (through 1 to 246) from Origin (1 to 81) to Destination (1 to 81)

[Andrei Bobrov]

You want 3d matrix?

[Fayyaz]

I want a matrix 81*81, but there should be multiple values in cells i.e. from Origin (1*81) to Destination (1*81), a vehicle can go through multiple locations i.e. (1 to 246). I don't know whether it should be 3d or not.

[Fayyaz]

@Andrei, the previous code was perfect, except instead of brackets there should be zero, and instead of 440*1 double, it should be 1.