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# ind2vec

Convert indices to vectors

ind2vec(ind)
ind2vec(ind,N)

## Description

ind2vec and vec2ind allow indices to be represented either by themselves, or as vectors containing a 1 in the row of the index they represent.

ind2vec(ind) takes one argument,

 ind Row vector of indices

and returns a sparse matrix of vectors, with one 1 in each column, as indicated by ind.

ind2vec(ind,N) returns an N-by-M matrix, where N can be equal to or greater than the maximum index.

## Examples

Here four indices are defined and converted to vector representation.

```ind = [1 3 2 3];
vec = ind2vec(ind)```
```vec =
(1,1)        1
(3,2)        1
(2,3)        1
(3,4)        1```

Here a vector with all zeros in the last row is converted to indices and back, while preserving the number of rows.

`vec = [0 0 1 0; 1 0 0 0; 0 1 0 0]'`
```vec =
0     1     0
0     0     1
1     0     0
0     0     0```
`[ind,n] = vec2ind(vec)`
```ind =
3     1     2

n =
4```
`vec2 = full(ind2vec(ind,n))`
```vec2 =
0     1     0
0     0     1
1     0     0
0     0     0```