# catboost.staged_predict

```
catboost.staged_predict(model,
pool,
verbose=FALSE,
prediction_type=None,
ntree_start=0,
ntree_end=0,
eval_period=1,
thread_count=-1)
```

## Purpose

Apply the model to the given dataset and calculate the results for the specified trees only.

Note

The model prediction results will be correct only if the features data in the `pool`

parameter contains all the features used in the model. Typically, the order of these features must match the order of the corresponding columns that is provided during the training. But if feature names are provided both during the training and in the `pool`

parameter when applying the model, they can be matched by names instead of the columns order.

## Arguments

### model

#### Description

The model obtained as the result of training.

**Default value**

Required argument

### pool

#### Description

The input dataset.

**Default value**

Required argument

### verbose

#### Description

Verbose output to stdout.

**Default value**

FALSE (not used)

### prediction_type

#### Description

The required prediction type.

Supported prediction types:

- Probability
- Class
- RawFormulaVal
- Exponent
- LogProbability

**Default value**

None (Exponent for Poisson and Tweedie, RawFormulaVal for all other loss functions)

### ntree_start

#### Description

To reduce the number of trees to use when the model is applied or the metrics are calculated, setthe range of the tree indices to`[ntree_start; ntree_end)`

and the the step of the trees to use to`eval_period`

.

This parameter defines the index of the first tree to be used when applying the model or calculating the metrics (the inclusive left border of the range). Indices are zero-based.

**Default value**

0

### ntree_end

#### Description

To reduce the number of trees to use when the model is applied or the metrics are calculated, setthe range of the tree indices to`[ntree_start; ntree_end)`

and the the step of the trees to use to`eval_period`

.

This parameter defines the index of the first tree not to be used when applying the model or calculating the metrics (the exclusive right border of the range). Indices are zero-based.

**Default value**

0 (the index of the last tree to use equals to the number of trees in the

model minus one)

### eval_period

#### Description

To reduce the number of trees to use when the model is applied or the metrics are calculated, setthe range of the tree indices to`[ntree_start; ntree_end)`

and the the step of the trees to use to`eval_period`

.

This parameter defines the step to iterate over the range `[`

ntree_start`; `

ntree_end`)`

. For example, let's assume that the following parameter values are set:

`ntree_start`

is set 0`ntree_end`

is set to N (the total tree count)`eval_period`

is set to 2

In this case, the results are returned for the following tree ranges: `[0, 2)`

, `[0, 4)`

, ... , `[0, N)`

.

**Default value**

1 (the trees are applied sequentially: the first tree, then the first two

trees, etc.)

### thread_count

#### Description

The number of threads to use for operation.

Optimizes the speed of execution. This parameter doesn't affect results.

**Default value**

-1 (the number of threads is equal to the number of processor cores)