Dissimilarity

One of the types of objects in Praat.

It represents a one-way table with dissimilarities between "objects".

### Creating a Dissimilarity from data in a text file

Suppose you have three objects A, B and C. In one way or another, you have acquired the following (symmetric) dissimilarities: δAB = 2 (= δBA) , δAC = 1 (= δCA), and δBC = 1.4 (= δCB), where δAB represents the dissimilarity between object A and object B.

You can create a simple text file like the following:

```    "ooTextFile" ! The line by which Praat can recognize your file``` ```    "Dissimilarity" ! The line that tells Praat about the contents``` ```    3 "A" "B" "C" ! Number of columns, and column labels``` ```    3 ! Number of rows``` ```    "A" 0 2 1 ! Row label (A), A-B value, A-C value``` ```    "B" 2 0 1.4 ! Row label (B), B-A value, B-C value``` ```    "C" 1 1.4 0 ! Row label (C), C-A value, C-B value```

Notice that:

• the row and column labels are identical.
• the matrix elements on the diagonal are zero.
• the matrix is symmetrical.

This text file can be read with the Read from file... command. Since a Dissimilarity object has the data structure of a square symmetrical TableOfReal, you could also start from an appropriate TableOfReal object and cast it to a Dissimilarity object.

### Commands

Creation

Confusion: To Dissimilarity...

Drawing

Draw as numbers...
Draw as squares...

Query

Get column mean (index)...
Get column mean (label)...
Get column stdev (index)...
Get column stdev (label)...

Modification

Formula...
Set value...
Remove column (index)...
Insert column (index)...
Set row label (index)...
Set row label (label)...
Set column label (index)...
Set column label (label)...

Multidimensional scaling analysis

Dissimilarity: To Configuration (monotone mds)...
Dissimilarity: To Configuration (i-spline mds)...
Dissimilarity: To Configuration (interval mds)...
Dissimilarity: To Configuration (ratio mds)...
Dissimilarity: To Configuration (absolute mds)...
Dissimilarity: To Configuration (kruskal)...
Transformations
Dissimilarity: To Distance...
Dissimilarity: To Weight