# predict

Label new data using semi-supervised self-trained classifier

## Description

## Examples

### Classify New Data Using Model Trained on Labeled and Unlabeled Data

Use both labeled and unlabeled data to train a `SemiSupervisedSelfTrainingModel`

object. Label new data using the trained model.

Randomly generate 15 observations of labeled data, with 5 observations in each of three classes.

rng('default') % For reproducibility labeledX = [randn(5,2)*0.25 + ones(5,2); randn(5,2)*0.25 - ones(5,2); randn(5,2)*0.5]; Y = [ones(5,1); ones(5,1)*2; ones(5,1)*3];

Randomly generate 300 additional observations of unlabeled data, with 100 observations per class.

unlabeledX = [randn(100,2)*0.25 + ones(100,2); randn(100,2)*0.25 - ones(100,2); randn(100,2)*0.5];

Fit labels to the unlabeled data by using a semi-supervised self-training method. The function `fitsemiself`

returns a `SemiSupervisedSelfTrainingModel`

object whose `FittedLabels`

property contains the fitted labels for the unlabeled data and whose `LabelScores`

property contains the associated label scores.

Mdl = fitsemiself(labeledX,Y,unlabeledX)

Mdl = SemiSupervisedSelfTrainingModel with properties: FittedLabels: [300x1 double] LabelScores: [300x3 double] ClassNames: [1 2 3] ResponseName: 'Y' CategoricalPredictors: [] Learner: [1x1 classreg.learning.classif.CompactClassificationECOC] Properties, Methods

Randomly generate 150 observations of new data, with 50 observations per class. For the purposes of validation, keep track of the true labels for the new data.

newX = [randn(50,2)*0.25 + ones(50,2); randn(50,2)*0.25 - ones(50,2); randn(50,2)*0.5]; trueLabels = [ones(50,1); ones(50,1)*2; ones(50,1)*3];

Predict the labels for the new data by using the `predict`

function of the `SemiSupervisedSelfTrainingModel`

object. Compare the true labels to the predicted labels by using a confusion matrix.

predictedLabels = predict(Mdl,newX); confusionchart(trueLabels,predictedLabels)

Only 8 of the 150 observations in `newX`

are mislabeled.

## Input Arguments

`Mdl`

— Semi-supervised self-training classifier

`SemiSupervisedSelfTrainingModel`

object

Semi-supervised self-training classifier, specified as a `SemiSupervisedSelfTrainingModel`

object returned by
`fitsemiself`

.

`X`

— Predictor data to be classified

numeric matrix | table

Predictor data to be classified, specified as a numeric matrix or table. Each row of
`X`

corresponds to one observation, and each column corresponds to
one variable.

If you trained `Mdl`

using matrix data (`X`

and
`UnlabeledX`

in the call to `fitsemiself`

), then
specify `X`

as a numeric matrix.

The variables in the columns of

`X`

must have the same order as the predictor variables that trained`Mdl`

.The software treats the predictors in

`X`

whose indices match`Mdl.CategoricalPredictors`

as categorical predictors.

If you trained `Mdl`

using tabular data (`Tbl`

and `UnlabeledTbl`

in the call to `fitsemiself`

),
then specify `X`

as a table.

All predictor variables in

`X`

must have the same variable names and data types as those that trained`Mdl`

(stored in`Mdl.PredictorNames`

). However, the column order of`X`

does not need to correspond to the column order of`Tbl`

. Also,`Tbl`

and`X`

can contain additional variables (for example, response variables), but`predict`

ignores them.`predict`

does not support multicolumn variables or cell arrays other than cell arrays of character vectors.

**Data Types: **`single`

| `double`

| `table`

## Output Arguments

`label`

— Predicted class labels

categorical array | character array | logical vector | numeric vector | cell array of character vectors

Predicted class labels, returned as a categorical or character array, logical or
numeric vector, or cell array of character vectors. `label`

has the
same data type as the fitted class labels `Mdl.FittedLabels`

, and its
length is equal to the number of rows in `X`

.

`score`

— Predicted class scores

numeric matrix

Predicted class scores, returned as a numeric matrix. `score`

has
size *m*-by-*K*, where *m* is the
number of observations (or rows) in `X`

and *K* is
the number of classes in `Mdl.ClassNames`

.

`score(m,k)`

is the likelihood that observation
`m`

in `X`

belongs to class `k`

,
where a higher score value indicates a higher likelihood. The range of score values
depends on the underlying classifier `Mdl.Learner`

.

## Version History

**Introduced in R2020b**

## See Also

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