Vowpal Wabbit

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### Setup Examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Sets up multiple examples within the Vowpal Wabbit workspace.

```cpp
void VW::setup_examples  | ( | VW::workspace & | _all_ ,   
|  | VW::multi_ex & | _examples_  
| ) | |   
```

--------------------------------

### Setup Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Sets up a single example within the Vowpal Wabbit workspace.

```cpp
void VW::setup_example  | ( | VW::workspace & | _all_ ,   
|  | example *  | _ae_  
| ) | |   
```

--------------------------------

### setup_example()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

If this example hasn’t already been setup (e.g., quadratic features constructed), do so.

```APIDOC
## setup_example()

### Description
If this example hasn’t already been setup (ie, quadratic features constructed, etc.), do so.
```

--------------------------------

### unsetup_example()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

If this example has been setup, reverse that process to allow further editing.

```APIDOC
## unsetup_example()

### Description
If this example has been setup, reverse that process so you can continue editing the examples.
```

--------------------------------

### learn

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.html

Learns on the current example. Automatically calls setup_example if the example has not yet been set up.

```APIDOC
## learn()

### Description
Learn on this example (and before learning, automatically call setup_example if the example hasn’t yet been setup).
```

--------------------------------

### Return Multiple Examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Returns multiple examples from the Vowpal Wabbit workspace.

```cpp
void VW::return_multiple_example  | ( | VW::workspace & | _all_ ,   
|  | VW::multi_ex & | _examples_  
| ) | |   
```

--------------------------------

### VW::setup_examples()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Sets up multiple examples for processing within the workspace.

```APIDOC
## VW::setup_examples()

### Description
Sets up multiple examples for processing within the workspace.

### Method
`void VW::setup_examples(VW::workspace & _all_, VW::multi_ex & _examples_)`
```

--------------------------------

### Example Creation

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.html

Create an example object associated with a Workspace instance.

```APIDOC
## example

### Description
Helper function to create an example object associated with this Workspace instance.

### Parameters
* **stringOrDict** (`Union[str, Dict[str, List[Union[Tuple[Union[str, int], float], str, int]]], Any, example, None]`) – See description in `__init__()` for valid values.
* **labelType** (`Union[int, LabelType, None]`) – See description in `__init__()` for valid values.

### Return Type
`Example`

### Returns
Constructed Example
```

--------------------------------

### get_prob

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Get probability from example prediction.

```APIDOC
## get_prob

### Description
Get probability from example prediction.

### Signature
`get_prob(_self: pylibvw.example_) -> float`
```

--------------------------------

### setup_examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_s.html

Sets up multiple examples for processing in Vowpal Wabbit.

```APIDOC
## setup_examples()

### Description
Prepares a batch or collection of examples for processing by the Vowpal Wabbit learning algorithm.

### Method
(Not specified, likely a function call)

### Endpoint
(Not applicable for C++ API)

### Parameters
(Not specified)

### Request Example
(Not applicable)

### Response
(Not specified)
```

--------------------------------

### get_pdf

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Get pdf from example prediction.

```APIDOC
## get_pdf

### Description
Get pdf from example prediction.

### Signature
`get_pdf(_self: pylibvw.example_) -> list`
```

--------------------------------

### VW::setup_example()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Sets up a single example for processing within the workspace.

```APIDOC
## VW::setup_example()

### Description
Sets up a single example for processing within the workspace.

### Method
`void VW::setup_example(VW::workspace & _all_, example * _ae_)`
```

--------------------------------

### setup_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_s.html

Sets up an individual example for processing in Vowpal Wabbit.

```APIDOC
## setup_example()

### Description
Prepares a single example for processing by the Vowpal Wabbit learning algorithm.

### Method
(Not specified, likely a function call)

### Endpoint
(Not applicable for C++ API)

### Parameters
(Not specified)

### Request Example
(Not applicable)

### Response
(Not specified)
```

--------------------------------

### get_scalars

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Get scalar values from example prediction.

```APIDOC
## get_scalars

### Description
Get scalar values from example prediction.

### Signature
`get_scalars(_self: pylibvw.example_) -> list`
```

--------------------------------

### get_multilabel_labels

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Get multilabel labels from example label.

```APIDOC
## get_multilabel_labels

### Description
Get multilabel labels from example label.

### Signature
`get_multilabel_labels(_self: pylibvw.example_) -> list`
```

--------------------------------

### get_decision_scores

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Get decision scores from example prediction.

```APIDOC
## get_decision_scores

### Description
Get decision scores from example prediction.

### Signature
`get_decision_scores(_self: pylibvw.example_) -> list`
```

--------------------------------

### setup_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Sets up an example for processing.

```APIDOC
## setup_example

### Description
Initializes or sets up an example structure for use within the VW workspace.

### Signature
`void setup_example (VW::workspace &all, example *ae)`
```

--------------------------------

### Example Management Functions

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Functions for setting up and retrieving examples from the Vowpal Wabbit workspace.

```APIDOC
## setup_examples (VW::workspace &all, VW::multi_ex &examples)

### Description
Sets up a collection of examples for use with the Vowpal Wabbit workspace.

### Signature
void setup_examples(VW::workspace &all, VW::multi_ex &examples)

## get_unused_example (VW::workspace *all)

### Description
Retrieves an unused example from the Vowpal Wabbit workspace.

### Signature
VW::example *get_unused_example(VW::workspace *all)
```

--------------------------------

### get_setupfn_name(reduction_setup_fn)

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1cached__learner-members.html

Gets the name of the reduction setup function.

```APIDOC
## get_setupfn_name(reduction_setup_fn)

### Description
Retrieves the name of the reduction setup function. This is typically used for introspection and debugging purposes.

### Method
override

### Parameters
* **reduction_setup_fn** (reduction_setup_fn) - The reduction setup function for which to get the name.
```

--------------------------------

### setup_examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_s.html

Sets up multiple examples for processing. Belongs to the VW namespace.

```APIDOC
## setup_examples()

### Description
Sets up multiple examples for processing.

### Namespace
VW
```

--------------------------------

### VW::setup_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/example_8h.html

Sets up an example structure for use with the Vowpal Wabbit workspace.

```APIDOC
## VW::setup_example

### Description
Initializes or prepares an example structure for processing within a Vowpal Wabbit workspace.

### Signature
`void setup_example(VW::workspace &all, example *ae)`

### Parameters
- `all` (*VW::workspace&*): Reference to the Vowpal Wabbit workspace.
- `ae` (*example*): Pointer to the example structure to be set up.
```

--------------------------------

### Get Prediction from Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

Retrieves a specific type of prediction from a Vowpal Wabbit example. Use this function when you need to extract predictions in a defined format.

```python
>>> from vowpalwabbit import Workspace, PredictionType, pyvw
>>> vw = Workspace(quiet=True)
>>> ex = vw.example('1 |a two features |b more features here')
>>> pyvw.get_prediction(ex, PredictionType.SCALAR)
0.0
```

--------------------------------

### VW::setup_examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/parser_8h.html

Sets up a collection of examples for processing within the Vowpal Wabbit workspace. This typically involves allocating or preparing example structures.

```APIDOC
## VW::setup_examples

### Description
Prepares a collection of examples for processing by the Vowpal Wabbit learning algorithm.

### Signature
```cpp
void setup_examples(VW::workspace &all, VW::multi_ex &examples)
```

### Parameters
* **all** (VW::workspace &) - The Vowpal Wabbit workspace containing global settings and state.
* **examples** (VW::multi_ex &) - A collection of examples to be set up.
```

--------------------------------

### VW::get_action_score_length

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW.html

Gets the number of action scores available for an example.

```APIDOC
## VW::get_action_score_length()

size_t VW::get_action_score_length(example * _ec_)
```

--------------------------------

### Example Handling

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/vw_8h.html

Functions for reading, creating, and manipulating examples within Vowpal Wabbit.

```APIDOC
## VW::is_ring_example

### Description
Checks if an example is part of a ring buffer.

### Signature
`bool is_ring_example (const VW::workspace &all, const example *ae)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `ae`: Pointer to the example to check.
```

```APIDOC
## VW::read_example

### Description
Reads an example from a string.

### Overloads

- `example * read_example (VW::workspace &all, const char *example_line)`
- `example * read_example (VW::workspace &all, const std::string &example_line)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `example_line`: The string representing the example.
```

```APIDOC
## VW::import_example

### Description
Imports an example with specified label and features.

### Signature
`example * import_example (VW::workspace &all, const std::string &label, primitive_feature_space *features, size_t len)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `label`: The label for the example.
- `features`: Pointer to the feature space.
- `len`: The number of features.
```

```APIDOC
## VW::alloc_examples

### Description
Allocates memory for a specified number of examples.

### Signature
`example * alloc_examples (size_t count)`

### Parameters

- `count`: The number of examples to allocate.
```

```APIDOC
## VW::dealloc_examples

### Description
Deallocates memory for a specified number of examples.

### Signature
`void dealloc_examples (example *example_ptr, size_t count)`

### Parameters

- `example_ptr`: Pointer to the beginning of the example memory.
- `count`: The number of examples to deallocate.
```

```APIDOC
## VW::parse_example_label

### Description
Parses the label of an example.

### Signature
`void parse_example_label (VW::workspace &all, example &ec, const std::string &label)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `ec`: The example to parse the label for.
- `label`: The label string.
```

```APIDOC
## VW::setup_examples

### Description
Sets up multiple examples for processing.

### Signature
`void setup_examples (VW::workspace &all, VW::multi_ex &examples)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `examples`: A collection of examples to set up.
```

```APIDOC
## VW::setup_example

### Description
Sets up a single example for processing.

### Signature
`void setup_example (VW::workspace &all, example *ae)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
- `ae`: Pointer to the example to set up.
```

```APIDOC
## VW::new_unused_example

### Description
Creates a new, unused example.

### Signature
`example * new_unused_example (VW::workspace &all)`

### Parameters

- `all`: The Vowpal Wabbit workspace.
```

```APIDOC
## VW::get_example

### Description
Retrieves an example from a parser.

### Signature
`example * get_example (parser *pf)`

### Parameters

- `pf`: Pointer to the parser.
```

--------------------------------

### Get Prediction from Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

Retrieves the prediction for an example. If prediction_type is None, it defaults to the workspace's prediction type. Deprecated: Supplying an int for prediction_type is deprecated.

```python
>>> from vowpalwabbit import Workspace, PredictionType
>>> vw = Workspace(quiet=True)
>>> ex = vw.example('1 |a two features |b more features here')
>>> ex.get_prediction()
0.0
```

--------------------------------

### setup_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_s.html

Sets up an example for processing. Belongs to the VW namespace.

```APIDOC
## setup_example()

### Description
Sets up an example for processing.

### Namespace
VW
```

--------------------------------

### Learn and Get Updated Prediction

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/basics.html

Train the model with an example and then retrieve the prediction for that same example after the update. The 'updated' prediction reflects the model's state post-learning.

```python
vw.learn(ex)
print(f"current prediction = {ex.get_updated_prediction()}")

```

--------------------------------

### num_features_in(_ns_)

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

Get the total number of features in a given namespace of an example.

```APIDOC
## num_features_in(_ns_)

### Description
Get the total number of features in a given namespace.

### Parameters
- **ns** (`Union`[`NamespaceId`, `str`, `int`]) - Required - namespace Get the total features of this namespace

### Return Type
`int`

### Returns
Total number of features in the given ns
```

--------------------------------

### ect_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_e.html

Sets up the example context for a reduction.

```APIDOC
## ect_setup()

### Description
Sets up the example context for a given reduction. This function is part of the reduction mechanism in Vowpal Wabbit.

### Signature
`void ect_setup(VW::reductions& reductions)`

### Parameters
* `reductions` (VW::reductions&): A reference to the reductions object.
```

--------------------------------

### get_or_calculate_order_independent_feature_space_hash()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/functions_func_g.html

Gets or calculates the order-independent feature space hash for an example prediction.

```APIDOC
## get_or_calculate_order_independent_feature_space_hash()

### Description
Gets or calculates the order-independent feature space hash for an example prediction.

### Signature
`uint64_t get_or_calculate_order_independent_feature_space_hash(const VW::example_predict& ec)`
```

--------------------------------

### binary_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_b.html

Sets up the binary reduction.

```APIDOC
## binary_setup()

### Description
Sets up the binary reduction.

### Namespace
VW::reductions
```

--------------------------------

### expreplay_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_e.html

Sets up the experience replay reduction.

```APIDOC
## expreplay_setup()

### Description
Sets up the experience replay (expreplay) reduction. This function initializes the necessary structures and parameters for using experience replay during training.

### Signature
`void expreplay_setup(VW::reductions& reductions)`

### Parameters
* `reductions` (VW::reductions&): A reference to the reductions object.
```

--------------------------------

### VW::get_unused_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/parser_8h.html

Retrieves an unused example structure from the Vowpal Wabbit workspace's pool. This is an efficient way to get an example object without reallocating memory.

```APIDOC
## VW::get_unused_example

### Description
Fetches an available example object from the workspace's internal pool for reuse.

### Signature
```cpp
VW::example &get_unused_example(VW::workspace *all)
```

### Parameters
* **all** (VW::workspace *) - Pointer to the Vowpal Wabbit workspace.

### Returns
A reference to an unused `VW::example` object.
```

--------------------------------

### parse_examples(VW::workspace *all, io_buf &buf, VW::multi_ex &examples, const uint8_t *buffer_pointer=nullptr, VW::experimental::api_status *status=nullptr)

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1parsers_1_1flatbuffer_1_1parser-members.html

Parses examples from a buffer into the provided multi_ex structure.

```APIDOC
## parse_examples(VW::workspace *all, io_buf &buf, VW::multi_ex &examples, const uint8_t *buffer_pointer=nullptr, VW::experimental::api_status *status=nullptr)

### Description
Parses examples from a buffer into the provided multi_ex structure. This method is used to deserialize example data from a flatbuffer format.

### Method
(Implicitly called)

### Parameters
- **all** (VW::workspace *) - Pointer to the Vowpal Wabbit workspace.
- **buf** (io_buf &) - The input buffer containing the data to parse.
- **examples** (VW::multi_ex &) - The structure to populate with parsed examples.
- **buffer_pointer** (const uint8_t *, optional) - A pointer to the buffer data. If nullptr, `buf` is used.
- **status** (VW::experimental::api_status *, optional) - Pointer to an API status object for error reporting.

### Response
(No explicit return value documented, likely modifies `examples` in place and uses `status` for errors.)
```

--------------------------------

### vowpalwabbit.pyvw.get_prediction(_ec_, _prediction_type_)

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.html

Gets a specified type of prediction from an example. Deprecated, use `get_prediction()` instead.

```APIDOC
## vowpalwabbit.pyvw.get_prediction(_ec_, _prediction_type_)

### Description
Get specified type of prediction from example
Deprecated since version 9.0.0: Use `get_prediction()` instead

### Parameters
* **ec** (Example) - Example
* **prediction_type** (Union[int, PredictionType]) – either the integer value of the `PredictionType` enum or the enum itself

### Returns
Prediction according to parameter prediction_type

### Example
```python
>>> from vowpalwabbit import Workspace, PredictionType, pyvw
>>> vw = Workspace(quiet=True)
>>> ex = vw.example('1 |a two features |b more features here')
>>> pyvw.get_prediction(ex, PredictionType.SCALAR)
0.0
```
```

--------------------------------

### plt_setup()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_p.html

Sets up the 'plt' reduction.

```APIDOC
## plt_setup()

### Description
Initializes and sets up the 'plt' (likely related to plotting or prediction logging) reduction.

### Signature
`VW::reductions plt_setup()`
```

--------------------------------

### Basic Vowpal Wabbit Workspace Usage

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.html

Demonstrates initializing a Vowpal Wabbit workspace, creating an example, learning from it, and making a prediction. Ensure Vowpal Wabbit is installed.

```python
from vowpalwabbit import Workspace, Example
workspace = Workspace(quiet=True)
ex = Example('1 | a b c')
workspace.learn(ex)
workspace.predict(ex)

```

--------------------------------

### Import Python Libraries for Vowpal Wabbit Slates

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/tutorials/python_slates.html

Import necessary Python libraries for Vowpal Wabbit, plotting, data manipulation, and numerical operations. Ensure these are installed before running the example.

```python
import vowpal_wabbit
import matplotlib.pyplot as plt
import pandas as pd
import random
import numpy as np
```

--------------------------------

### get_example()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_g.html

Retrieves an example from Vowpal Wabbit.

```APIDOC
## get_example()

### Description
Retrieves an example from Vowpal Wabbit.

### Signature
`VW get_example()`
```

--------------------------------

### gd_setup()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_func_g.html

Sets up the Gradient Descent reduction.

```APIDOC
## gd_setup()

### Description
Sets up the Gradient Descent reduction.

### Signature
`VW::reductions gd_setup()`
```

--------------------------------

### Contextual Bandit (CB) Loop Example

Source: https://vowpalwabbit.org/docs/reinforcement_learning/cpp/latest/rl_sim_8cc-example.html

Implements the loop for a Contextual Bandit problem. It repeatedly picks a person, gets their features, chooses an action using the RL model, and reports the outcome.

```cpp
int rl_sim::cb_loop()
{
r::ranking_response response;
simulation_stats<size_t> stats;
while (_run_loop)
{
auto& p = pick_a_random_person();
const auto context_features = p.get_features();
const auto action_features = get_action_features();
const auto context_json = create_context_json(context_features, action_features);
const auto req_id = create_event_id();
r::api_status status;
// Choose an action
if (_rl->choose_rank(req_id.c_str(), context_json.c_str(), response, &status) != err::success)
{
std::cout << status.get_error_msg() << std::endl;
continue;
}
// Use the chosen action
size_t chosen_action = 0;
if (response.get_chosen_action_id(chosen_action) != err::success)
{
std::cout << status.get_error_msg() << std::endl;
continue;
}
// What outcome did this action get?
const auto outcome = p.get_outcome(_topics[chosen_action], _random_seed);
// Report outcome received
if (_rl->report_outcome(req_id.c_str(), outcome, &status) != err::success && outcome > 0.00001f)
{
std::cout << status.get_error_msg() << std::endl;
continue;
}
stats.record(p.id(), chosen_action, outcome);
if (!_quiet)
{
std::cout << " " << stats.count() << ", ctxt, " << p.id() << ", action, " << chosen_action << ", outcome, "
<< outcome << ", dist, " << get_dist_str(response) << ", " << stats.get_stats(p.id(), chosen_action)
<< std::endl;
}
std::this_thread::sleep_for(std::chrono::milliseconds(_delay));
}
return 0;
}
```

--------------------------------

### cb_explore_setup Function

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/cb__explore_8h.html

The `cb_explore_setup` function is part of the Vowpal Wabbit reductions for contextual bandits. It is responsible for initializing the exploration mechanism.

```APIDOC
## VW::reductions::cb_explore_setup

### Description
Sets up the contextual bandit exploration reducer.

### Signature
std::shared_ptr< VW::LEARNER::learner > cb_explore_setup(VW::setup_base_i &stack_builder)

### Parameters
* `stack_builder` (VW::setup_base_i &): The stack builder interface for setting up the learner.

### Returns
A shared pointer to the initialized learner for contextual bandit exploration.
```

--------------------------------

### start() and Start()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1spanning__tree.html

Initiates the spanning tree process. Start() is deprecated.

```APIDOC
## start()

### Description
Initiates the spanning tree process. This is typically a non-blocking call that starts the process in the background.

### Method
void
```

```APIDOC
## Start()

### Description
Initiates the spanning tree process. This method is deprecated and will be removed in VW 10. Use `start()` instead.

### Method
void
```

--------------------------------

### CB Explore Setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the CB explore reduction.

```APIDOC
## cb_explore_setup

### Description
Sets up the CB explore reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > cb_explore_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### Set Label and Train on Test Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/basics.html

Assign a label to a test example and train the model on it multiple times. This converts the test example into a training example.

```python
ex2.set_label_string("-2.0")
for _ in range(5):
    vw.learn(ex2)

print(f"current prediction = {ex2.get_updated_prediction()}")

```

--------------------------------

### Cost Sensitive Example Header Check

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/cost__sensitive_8h.html

Checks if an example is a cost-sensitive example header.

```APIDOC
## VW::is_cs_example_header

### Description
Checks if the provided `VW::example` is a cost-sensitive example header.

### Signature
```cpp
bool VW::is_cs_example_header(const VW::example &ec)
```

### Parameters
- **ec** (const VW::example &): The example to check.
```

--------------------------------

### expreplay_setup function

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/expreplay_8h.html

The `expreplay_setup` function is a factory function used to create and initialize an expreplay learner.

```APIDOC
## expreplay_setup

### Description
Factory function to set up and initialize an expreplay learner.

### Signature
```cpp
template<char er_level, VW::label_parser & lp>
std::shared_ptr< VW::LEARNER::learner > expreplay_setup(VW::setup_base_i &stack_builder)
```

### Parameters
* `stack_builder`: The stack builder object used for setting up the learner.
```

--------------------------------

### Example Class Methods

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.html

Methods available for the Example class, used for constructing and manipulating training examples.

```APIDOC
## Example Class

### Description
Provides methods for creating, modifying, and accessing features and labels within a Vowpal Wabbit example.

### Methods
- `__init__()`: Initializes an Example object.
- `ensure_namespace_exists(ns)`: Ensures a namespace exists in the example.
- `feature(name, value)`: Adds or updates a feature with a given name and value.
- `feature_weight(name, weight)`: Sets the weight for a feature.
- `finished`: Property indicating if the example setup is complete.
- `get_feature_id(ns, name)`: Retrieves the ID of a feature within a namespace.
- `get_label()`: Retrieves the label associated with the example.
- `get_ns(ns)`: Retrieves a namespace object.
- `get_prediction()`: Retrieves the prediction for the example.
- `iter_features()`: Iterates over the features in the example.
- `labelType`: Property to get the type of label.
- `learn()`: Processes the example for learning.
- `num_features_in(ns)`: Returns the number of features in a namespace.
- `pop_feature(ns, name)`: Removes a feature from a namespace.
- `pop_namespace(ns)`: Removes a namespace from the example.
- `push_feature(ns, name, value)`: Adds a feature to a namespace.
- `push_features(ns, features)`: Adds multiple features to a namespace.
- `push_hashed_feature(ns, index, value)`: Adds a hashed feature.
- `push_namespace(ns)`: Adds a namespace to the example.
- `set_label_string(label_str)`: Sets the label using a string representation.
- `setup_done`: Property indicating if the example setup is done.
- `setup_example()`: Sets up the example for processing.
- `stride`: Property for stride information.
- `sum_feat_sq(ns)`: Calculates the sum of squared feature values in a namespace.
- `unsetup_example()`: Cleans up example setup.
- `vw`: Property to access the Vowpal Wabbit instance.
```

--------------------------------

### topk_setup()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Initializes the top-k reduction strategy. This is useful for problems where selecting the top k actions or items is the goal.

```APIDOC
## topk_setup()

### Description
Initializes the top-k reduction strategy for selecting top actions or items.

### Signature
std::shared_ptr< VW::LEARNER::learner > VW::reductions::topk_setup(VW::setup_base_i &, VW::LEARNER::stack_builder &)

### Parameters
* **setup_base_i** (VW::setup_base_i &) - The setup interface for Vowpal Wabbit.
* **_stack_builder_** (VW::LEARNER::stack_builder &) - The stack builder for managing reduction layers.
```

--------------------------------

### Cost Sensitive Example Header Check (Alternative)

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/cost__sensitive_8h.html

Checks if an example is a cost-sensitive example header (alternative implementation).

```APIDOC
## VW::ec_is_example_header

### Description
Checks if the provided `VW::example` is a cost-sensitive example header.

### Signature
```cpp
bool VW::ec_is_example_header(VW::example const &ec)
```

### Parameters
- **ec** (VW::example const &): The example to check.
```

--------------------------------

### Iterate Learning Between Two Examples

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/basics.html

Alternate learning between two examples, `ex` and `ex2`, over several iterations. This demonstrates how training on one example can influence predictions on others, and shows the predictions for both examples after each iteration.

```python
ex.set_label_string("1")
for i in range(10):
    vw.learn(ex)
    vw.learn(ex2)
    print(f"ex prediction = {ex.get_updated_prediction()}")
    print(f"ex2 prediction = {ex2.get_updated_prediction()}")

```

--------------------------------

### Efficient Example Management

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/predict.html

Demonstrates how to manage a list of examples efficiently, including creating and finishing them to allow Vowpal Wabbit to reuse memory.

```python
exList = []
for i in range(120):
    ex = vw.example()
    exList.append(ex)

# this is the safe way to delete the examples for VW to reuse:
for ex in exList:
    vw.finish_example(ex)

exList = []  # this should __del__ the examples, we hope :)
for i in range(120):
    ex = vw.example()
    exList.append(ex)

for ex in exList:
    vw.finish_example(ex)
```

--------------------------------

### next(VW::workspace &all, io_buf &buf, VW::multi_ex &examples) override

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1parsers_1_1csv_1_1csv__parser-members.html

Parses the next example from the input buffer.

```APIDOC
## next(VW::workspace &all, io_buf &buf, VW::multi_ex &examples) override

### Description
This is the core method for parsing the next example from the provided input buffer (`io_buf`). It populates the `VW::multi_ex` structure with the parsed example data, using the `VW::workspace` context. This method overrides a virtual function from the base `input_parser` class.

### Parameters
* **all** (VW::workspace &) - The Vowpal Wabbit workspace containing global settings and data.
* **buf** (io_buf &) - The input buffer containing the data to be parsed.
* **examples** (VW::multi_ex &) - A multi-example structure to store the parsed example.
```

--------------------------------

### start()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1spanning__tree-members.html

Starts the spanning tree.

```APIDOC
## start()

### Description
Starts the spanning tree. This function initiates the operation of the spanning tree.

### Method
(Implicitly called, likely a starter)

### Endpoint
N/A

### Parameters
None

### Request Example
```cpp
st.start();
```

### Response
None (Typically starts a process or performs an action)
```

--------------------------------

### topk_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the Top-K learning algorithm.

```APIDOC
## topk_setup

### Description
Sets up the Top-K learning algorithm.

### Signature
std::shared_ptr< VW::LEARNER::learner > topk_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### Create Example from Dictionary

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/basics.html

Create a Vowpal Wabbit example using Python dictionaries. This maps namespaces to lists of features, which can be strings or (string, float) pairs. This example is created without a label, making it a test example.

```python
ex2 = vw.example({"a": ["features"], "b": ["more", "features", "there"]})

```

--------------------------------

### cbify_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the cbify reduction.

```APIDOC
## cbify_setup()

### Description
Sets up the cbify reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > VW::reductions::cbify_setup(VW::setup_base_i & _stack_builder_)
```

--------------------------------

### Example Management Functions

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/vw_8h.html

Functions for managing and manipulating Vowpal Wabbit examples, including adding labels, finishing, and emptying examples.

```APIDOC
## add_constant_feature

### Description
Adds a constant feature to a Vowpal Wabbit example.

### Signature
`void VW::add_constant_feature (const VW::workspace &all, example *ec)`

## add_label

### Description
Adds a label to a Vowpal Wabbit example.

### Signature
`void VW::add_label (example *ec, float label, float weight=1, float base=0)`

## finish_example

### Description
Cleans up and finalizes a Vowpal Wabbit example.

### Signature
`void VW::finish_example (VW::workspace &all, example &ec)`
`void VW::finish_example (VW::workspace &all, multi_ex &ec)`

## empty_example

### Description
Resets a Vowpal Wabbit example, freeing its resources.

### Signature
`void VW::empty_example (VW::workspace &all, example &ec)`
```

--------------------------------

### VW::LEARNER::ec_is_example_header

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/learner_8h.html

Checks if a given example is an example header based on its label type. This is useful for parsing multi-line examples.

```APIDOC
## VW::LEARNER::ec_is_example_header

### Description
Checks if a given example is an example header based on its label type. This is useful for parsing multi-line examples.

### Signature
```cpp
bool ec_is_example_header(example const &ec, label_type_t label_type)
```

### Parameters
* `ec` (example const &): A constant reference to the example to check.
* `label_type` (label_type_t): The label type to check against.
```

--------------------------------

### lrqfa_setup Function

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/lrqfa_8h.html

The `lrqfa_setup` function initializes and returns a shared pointer to the LRQFA learner. It is part of the `VW::reductions` namespace and requires a `VW::setup_base_i` object for setup.

```APIDOC
## VW::reductions::lrqfa_setup

### Description
Sets up the LRQFA (Linear Regression Quantile Factorization Algorithm) learner.

### Signature
std::shared_ptr< VW::LEARNER::learner > lrqfa_setup(VW::setup_base_i &stack_builder)

### Parameters
* `stack_builder` (VW::setup_base_i &) - The base interface for setting up the learner stack.

### Returns
A `std::shared_ptr` to the initialized `VW::LEARNER::learner` object for LRQFA.
```

--------------------------------

### CB Algs Setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the CB algorithms reduction.

```APIDOC
## cb_algs_setup

### Description
Sets up the CB algorithms reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > cb_algs_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### Start

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/functions_func_s.html

Starts a spanning tree process.

```APIDOC
## Start

### Description
Initiates the process related to a spanning tree.

### Signature
`void Start(VW::spanning_tree &)`
```

--------------------------------

### cb_sample_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the cb_sample reduction.

```APIDOC
## cb_sample_setup()

### Description
Sets up the cb_sample reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > VW::reductions::cb_sample_setup(VW::setup_base_i & _stack_builder_)
```

--------------------------------

### read_span_flatbuffer

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/parse__example__flatbuffer_8h.html

Reads a span of flatbuffer data and converts it into Vowpal Wabbit examples. It supports custom example factories and optional example sinks.

```APIDOC
## read_span_flatbuffer

### Description
Reads a span of flatbuffer data and converts it into Vowpal Wabbit examples. Supports custom example factories and optional example sinks.

### Signature
`int VW::parsers::flatbuffer::read_span_flatbuffer(VW::workspace *all, const uint8_t *span, size_t length, example_factory_t example_factory, VW::multi_ex &examples, example_sink_f example_sink = nullptr, VW::experimental::api_status *status = nullptr)`

### Parameters
- **all** (`VW::workspace *`): Pointer to the Vowpal Wabbit workspace.
- **span** (`const uint8_t *`): Pointer to the beginning of the flatbuffer data span.
- **length** (`size_t`): The length of the flatbuffer data span.
- **example_factory** (`example_factory_t`): A function to create new examples.
- **examples** (`VW::multi_ex &`): The container to store the converted examples.
- **example_sink** (`example_sink_f`, optional): A function to process examples as they are read. Defaults to `nullptr`.
- **status** (`VW::experimental::api_status *`, optional): Pointer to an API status object for error reporting. Defaults to `nullptr`.
```

--------------------------------

### output_and_account_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1details.html

Outputs an example and accounts for it in the Vowpal Wabbit workspace.

```APIDOC
## output_and_account_example()

### Description
Outputs the provided example to the configured output streams and updates the Vowpal Wabbit workspace's internal accounting based on the example.

### Parameters
- **_all_** (VW::workspace &) - The Vowpal Wabbit workspace object.
- **_ec_** (const VW::example &) - A constant reference to the example to be processed.
```

--------------------------------

### substring_to_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1parsers_1_1text_1_1details.html

Converts a string view representing an example into a Vowpal Wabbit example structure. This function is used for parsing individual examples from text.

```APIDOC
## substring_to_example()

### Description
Converts a string view representing an example into a Vowpal Wabbit example structure.

### Parameters
- **_all_** (VW::workspace*): Pointer to the Vowpal Wabbit workspace.
- **_ae_** (VW::example*): Pointer to the Vowpal Wabbit example structure to populate.
- **_example_** (VW::string_view): A string view containing the text representation of the example.
```

--------------------------------

### CB Sample Setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the CB sample reduction.

```APIDOC
## cb_sample_setup

### Description
Sets up the CB sample reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > cb_sample_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### Start()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1spanning__tree-members.html

Inline function to start the spanning tree.

```APIDOC
## Start()

### Description
An inline function to start the spanning tree. This may be an alias or a more optimized version of `run()`.

### Method
(Implicitly called, likely a starter)

### Endpoint
N/A

### Parameters
None

### Request Example
```cpp
st.Start();
```

### Response
None (Typically starts a process or performs an action)
```

--------------------------------

### get_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_g.html

Retrieves an example.

```APIDOC
## get_example()

### Description
Fetches a single example from the dataset or internal storage.

### Type
VW
```

--------------------------------

### example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/functions_func_e.html

Represents a single example in Vowpal Wabbit.

```APIDOC
## example()

### Description
Represents a single data example used for training or prediction in Vowpal Wabbit. It encapsulates features, label, and other relevant information.

### Signature
`example() : VW::example`
```

--------------------------------

### CBify Setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the CBify reduction.

```APIDOC
## cbify_setup

### Description
Sets up the CBify reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > cbify_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### learn

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1workspace.html

Learns from a single example or a collection of examples.

```APIDOC
## learn

### Description
Learns from a single example or a collection of examples.

### Method Signature
- `void learn(example &)`
- `void learn(multi_ex &)`
```

--------------------------------

### Create and Learn from a New Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/predict.html

Constructs a new example from scratch, sets its label and features, and then learns from it multiple times. It also calculates and compares custom and Vowpal Wabbit predictions.

```python
print("# make our own example from scratch")
ex = vw.example()
ex.set_label_string("0")
ex.push_features("x", ["a", "b"])
ex.push_features("y", [("c", 1.0)])
ex.setup_example()

print(
    "        my view of example =",
    str([(f, v, vw.get_weight(f)) for f, v in ex.iter_features()]),
)
my_pred2 = my_predict(vw, ex)
print("     my partial prediction =", my_pred2)
ensure_close(my_pred, my_pred2)

ex.learn()
ex.learn()
ex.learn()
ex.learn()
print("  final partial prediction =", ex.get_updated_prediction())
ensure_close(ex.get_updated_prediction(), my_predict(vw, ex))
print("")
vw.finish_example(ex)
```

--------------------------------

### is_multiline()

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1polymorphic__ex.html

Checks if the current example is a multiline example.

```APIDOC
## is_multiline()

### Description
Checks if the current example is a multiline example.

### Signature
`bool VW::polymorphic_ex::is_multiline() const`

### Returns
`true` if the example is multiline, `false` otherwise.
```

--------------------------------

### mf_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the Matrix Factorization (MF) learning algorithm.

```APIDOC
## mf_setup

### Description
Sets up the Matrix Factorization (MF) learning algorithm.

### Signature
std::shared_ptr< VW::LEARNER::learner > mf_setup (VW::setup_base_i &stack_builder)
```

--------------------------------

### Observe Impact on Original Example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/examples/basics.html

After training on a new example, observe how it affects the prediction of a previously trained example by removing its label, learning, and printing the prediction.

```python
ex.set_label_string("")
vw.learn(ex)
print(f"current prediction = {ex.get_updated_prediction()}")

```

--------------------------------

### VW::parser::reader

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1parser.html

A function pointer that reads and parses examples from an io_buf. It consumes the io_buf and produces parsed examples, with the number of produced examples being implementation-defined.

```APIDOC
## VW::parser::reader

### Description
A function pointer that reads and parses examples from an `io_buf`. It consumes the `io_buf` and produces parsed examples. The number of produced examples is implementation-defined. For single-line parsers, a single example is produced. For multi-line parsers, multiple examples are produced, all corresponding to the same overall logical example. The `examples` must contain a single empty example when this call is made.

### Type
`int(*)(VW::workspace *, io_buf &, VW::multi_ex &examples)`
```

--------------------------------

### gd_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_g.html

Sets up the Gradient Descent learner.

```APIDOC
## gd_setup()

### Description
Configures the standard Gradient Descent learning algorithm.

### Namespace
VW::reductions
```

--------------------------------

### gd_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the gd reduction.

```APIDOC
## gd_setup()

### Description
Sets up the gd reduction.

### Signature
std::shared_ptr< VW::LEARNER::learner > VW::reductions::gd_setup(VW::setup_base_i & _stack_builder_)
```

--------------------------------

### start

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/functions_s.html

Starts the spanning tree process (lowercase variant).

```APIDOC
## start()

### Description
Starts the spanning tree process (lowercase variant).

### Signature
`VW::spanning_tree start()`
```

--------------------------------

### bs_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_b.html

Sets up the BS (likely Bootstrap Sampling) reduction.

```APIDOC
## bs_setup()

### Description
Sets up the BS (likely Bootstrap Sampling) reduction.

### Namespace
VW::reductions
```

--------------------------------

### Start

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/functions_s.html

Starts the spanning tree process (uppercase variant).

```APIDOC
## Start()

### Description
Starts the spanning tree process (uppercase variant).

### Signature
`VW::spanning_tree Start()`
```

--------------------------------

### append_example_namespaces_from_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1details.html

Appends namespaces from a source example to a target example.

```APIDOC
## append_example_namespaces_from_example()

Appends namespaces from a source example to a target example.

### Signature

```cpp
void VW::details::append_example_namespaces_from_example(VW::example & _target_, const VW::example & _source_)
```

### Parameters

- `_target_` (VW::example &): The target example to which namespaces will be appended.
- `_source_` (const VW::example &): The source example from which namespaces will be copied.
```

--------------------------------

### expreplay_setup

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespaceVW_1_1reductions.html

Sets up the expreplay reduction with a specified level and label parser.

```APIDOC
## expreplay_setup<char er_level, VW::label_parser & lp>()

### Description
Sets up the expreplay reduction with a specified level and label parser.

### Signature
std::shared_ptr< VW::LEARNER::learner > VW::reductions::expreplay_setup<char er_level, VW::label_parser & lp>(VW::setup_base_i & _stack_builder_)
```

--------------------------------

### read_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/namespacemembers_r.html

Reads a single example. Returns the example object.

```APIDOC
## read_example()

### Description
Reads a single example.

### Returns
`VW` - The read example.
```

--------------------------------

### pylibvw.example.__init__

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/python/latest/reference/vowpalwabbit.pyvw.pylibvw.html

Constructs an empty example. A label type must be provided.

```APIDOC
## pylibvw.example.__init__

### Description
Construct an empty example; you must provide a label type.

### Signature
`__init__(self: pylibvw.example, arg0: pylibvw.vw, arg1: typing.SupportsInt | typing.SupportsIndex, arg2: pylibvw.example) -> None`
```

--------------------------------

### process_example

Source: https://vowpalwabbit.org/docs/vowpal_wabbit/cpp/latest/classVW_1_1reductions_1_1automl_1_1interaction__config__manager.html

Processes an incoming example for interaction configuration.

```APIDOC
## void process_example()

template<typename config_oracle_impl , typename estimator_impl >
void VW::reductions::automl::interaction_config_manager< config_oracle_impl, estimator_impl >::process_example(
  const multi_ex & _ec_
)
```
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