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SOMDESCRIBE procedure

Summarizes values of variables at nodes of a self-organizing map (R.W. Payne).

Options

PRINT = string token Controls whether or not the summaries are printed (summaries); default summ
DATA = matrix or pointer Data values to identify the positions of the samples on the map
SOM = pointer Specifies the map
NEWSOM = pointer Saves the map, augmented by the summary information

Parameters

Y = variates or factors Data values to be summarized
METHOD = string tokens How to summarize each Y (mean, mode, median, minimum, maximum, sd, variance); default mode for factors, mean for variates

Description

A self-organizing map is a two dimensional grid of nodes, used to classify vectors of observations on p variables. Each node is characterized by a vector of p weights (one for each variable); these can be estimated, from a training dataset, by procedure SOMESTIMATE. This procedure, SOMDESCRIBE, allows you to allocate observations to the nodes of a map and form summaries of their values.

The SOM option supplies the information about the self-organizing map, which will have been saved in a pointer using the SOM parameter of SOMESTIMATE. The DATA option supplies the variables required to identify the positions of the samples on the map, either as a matrix with n rows and p columns (where n is the number of samples) or as a pointer containing p variates each with n units. The SOMIDENTIFY procedure, called by SOMDESCRIBE to identify the positions, will issue a warning if the variables have different names to those in the data set used by SOMESTIMATE to form the map. The NEWSOM option can be used to save an extended form of the self-organizing map which also contains the summary information. This extended map can then be used by SOMPREDICT to form predictions for future observations.

The information to be summarized at each node is supplied by the Y parameter, as a list of variates and/or factors. The METHOD parameter supplies a list of strings, defining how each one is to be summarized: either mean, mode, median, minimum, maximum, sd (i.e. standard deviation) or variance.

The PRINT option controls whether or not the summaries are printed (by default they will be printed).

Options: PRINT, DATA, SOM, NEWSOM.

Parameters: Y, METHOD.

Method

The SOMIDENTIFY procedure is used to allocate the samples to the nodes of the map. The TABMODE procedure is used to form modes, and the TABULATE directive to form the other types of summary.

Action with RESTRICT

SOMDESCRIBE takes account of any restrictions defined on the Y variates or factors.

See also

Procedures: SOM, SOMADJUST, SOMESTIMATE, SOMIDENTIFY, SOMPREDICT.

Commands for: Data mining.

Example

CAPTION 'SOMDESCRIBE example',!t('Fisher''s Iris Data'); STYLE=meta,plain
SOM     Som; VARIABLENAMES=!t(Sepal_L,Sepal_W,Petal_L,Petal_W)
MATRIX  [ROWS=150; COLUMNS=!t(Sepal_L,Sepal_W,Petal_L,Petal_W)] Measures
READ    Measures
 5.1  3.5  1.4  0.2
 4.9  3.0  1.4  0.2
 4.7  3.2  1.3  0.2
 4.6  3.1  1.5  0.2
 5.0  3.6  1.4  0.2
 5.4  3.9  1.7  0.4
 4.6  3.4  1.4  0.3
 5.0  3.4  1.5  0.2
 4.4  2.9  1.4  0.2
 4.9  3.1  1.5  0.1
 5.4  3.7  1.5  0.2
 4.8  3.4  1.6  0.2
 4.8  3.0  1.4  0.1
 4.3  3.0  1.1  0.1
 5.8  4.0  1.2  0.2
 5.7  4.4  1.5  0.4
 5.4  3.9  1.3  0.4
 5.1  3.5  1.4  0.3
 5.7  3.8  1.7  0.3
 5.1  3.8  1.5  0.3
 5.4  3.4  1.7  0.2
 5.1  3.7  1.5  0.4
 4.6  3.6  1.0  0.2
 5.1  3.3  1.7  0.5
 4.8  3.4  1.9  0.2
 5.0  3.0  1.6  0.2
 5.0  3.4  1.6  0.4
 5.2  3.5  1.5  0.2
 5.2  3.4  1.4  0.2
 4.7  3.2  1.6  0.2
 4.8  3.1  1.6  0.2
 5.4  3.4  1.5  0.4
 5.2  4.1  1.5  0.1
 5.5  4.2  1.4  0.2
 4.9  3.1  1.5  0.2
 5.0  3.2  1.2  0.2
 5.5  3.5  1.3  0.2
 4.9  3.6  1.4  0.1
 4.4  3.0  1.3  0.2
 5.1  3.4  1.5  0.2
 5.0  3.5  1.3  0.3
 4.5  2.3  1.3  0.3
 4.4  3.2  1.3  0.2
 5.0  3.5  1.6  0.6
 5.1  3.8  1.9  0.4
 4.8  3.0  1.4  0.3
 5.1  3.8  1.6  0.2
 4.6  3.2  1.4  0.2
 5.3  3.7  1.5  0.2
 5.0  3.3  1.4  0.2
 7.0  3.2  4.7  1.4
 6.4  3.2  4.5  1.5
 6.9  3.1  4.9  1.5
 5.5  2.3  4.0  1.3
 6.5  2.8  4.6  1.5
 5.7  2.8  4.5  1.3
 6.3  3.3  4.7  1.6
 4.9  2.4  3.3  1.0
 6.6  2.9  4.6  1.3
 5.2  2.7  3.9  1.4
 5.0  2.0  3.5  1.0
 5.9  3.0  4.2  1.5
 6.0  2.2  4.0  1.0
 6.1  2.9  4.7  1.4
 5.6  2.9  3.6  1.3
 6.7  3.1  4.4  1.4
 5.6  3.0  4.5  1.5
 5.8  2.7  4.1  1.0
 6.2  2.2  4.5  1.5
 5.6  2.5  3.9  1.1
 5.9  3.2  4.8  1.8
 6.1  2.8  4.0  1.3
 6.3  2.5  4.9  1.5
 6.1  2.8  4.7  1.2
 6.4  2.9  4.3  1.3
 6.6  3.0  4.4  1.4
 6.8  2.8  4.8  1.4
 6.7  3.0  5.0  1.7
 6.0  2.9  4.5  1.5
 5.7  2.6  3.5  1.0
 5.5  2.4  3.8  1.1
 5.5  2.4  3.7  1.0
 5.8  2.7  3.9  1.2
 6.0  2.7  5.1  1.6
 5.4  3.0  4.5  1.5
 6.0  3.4  4.5  1.6
 6.7  3.1  4.7  1.5
 6.3  2.3  4.4  1.3
 5.6  3.0  4.1  1.3
 5.5  2.5  4.0  1.3
 5.5  2.6  4.4  1.2
 6.1  3.0  4.6  1.4
 5.8  2.6  4.0  1.2
 5.0  2.3  3.3  1.0
 5.6  2.7  4.2  1.3
 5.7  3.0  4.2  1.2
 5.7  2.9  4.2  1.3
 6.2  2.9  4.3  1.3
 5.1  2.5  3.0  1.1
 5.7  2.8  4.1  1.3
 6.3  3.3  6.0  2.5
 5.8  2.7  5.1  1.9
 7.1  3.0  5.9  2.1
 6.3  2.9  5.6  1.8
 6.5  3.0  5.8  2.2
 7.6  3.0  6.6  2.1
 4.9  2.5  4.5  1.7
 7.3  2.9  6.3  1.8
 6.7  2.5  5.8  1.8
 7.2  3.6  6.1  2.5
 6.5  3.2  5.1  2.0
 6.4  2.7  5.3  1.9
 6.8  3.0  5.5  2.1
 5.7  2.5  5.0  2.0
 5.8  2.8  5.1  2.4
 6.4  3.2  5.3  2.3
 6.5  3.0  5.5  1.8
 7.7  3.8  6.7  2.2
 7.7  2.6  6.9  2.3
 6.0  2.2  5.0  1.5
 6.9  3.2  5.7  2.3
 5.6  2.8  4.9  2.0
 7.7  2.8  6.7  2.0
 6.3  2.7  4.9  1.8
 6.7  3.3  5.7  2.1
 7.2  3.2  6.0  1.8
 6.2  2.8  4.8  1.8
 6.1  3.0  4.9  1.8
 6.4  2.8  5.6  2.1
 7.2  3.0  5.8  1.6
 7.4  2.8  6.1  1.9
 7.9  3.8  6.4  2.0
 6.4  2.8  5.6  2.2
 6.3  2.8  5.1  1.5
 6.1  2.6  5.6  1.4
 7.7  3.0  6.1  2.3
 6.3  3.4  5.6  2.4
 6.4  3.1  5.5  1.8
 6.0  3.0  4.8  1.8
 6.9  3.1  5.4  2.1
 6.7  3.1  5.6  2.4
 6.9  3.1  5.1  2.3
 5.8  2.7  5.1  1.9
 6.8  3.2  5.9  2.3
 6.7  3.3  5.7  2.5
 6.7  3.0  5.2  2.3
 6.3  2.5  5.0  1.9
 6.5  3.0  5.2  2.0
 6.2  3.4  5.4  2.3
 5.9  3.0  5.1  1.8  :
FACTOR       [NVALUES=150; LABELS=!t(Setosa,Versicolor,Virginica);\
             VALUES=50(1,2,3)] Species
SOMESTIMATE  [PRINT=weights,report; PLOT=*; NCYCLE=!(100,200);\
             SIGMA=!(5,1)] Som; DATA=Measures; SEED=419749
SOMDESCRIBE  [DATA=Measures; SOM=Som] Species
Updated on June 18, 2019

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