FeatureBlock

All Implemented Interfaces:
```
public final class FeatureBlock

                    
```
A contiguous memory block storing numerical feature vectors for all nodes in a FeaturedDocument.
Instead of allocating a separate double array per node (as org.apache.commons.math3.linear.ArrayRealVector does), this class stores all node feature vectors in a single DoubleArray, indexed by nodeIndex * dimension + featureKey.
Benefits:
- Single allocation per document instead of N allocations per node
- Contiguous memory improves cache locality
- Reduced GC pressure from fewer heap objects

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description

Field Summary

Fields
Modifier and Type	Field	Description
`private final Integer`	`nodeCount`
`private final Integer`	`dimension`

Constructor Summary

Constructors
Constructor	Description
`FeatureBlock(Integer nodeCount, Integer dimension)`

Enum Constant Summary

Enum Constants
Enum Constant	Description

Method Summary

Modifier and Type	Method	Description
`final Integer`	`getNodeCount()`
`final Integer`	`getDimension()`
`final Double`	`get(Integer nodeIndex, Integer featureKey)`	Get a feature value for a node.
`final Unit`	`set(Integer nodeIndex, Integer featureKey, Double value)`	Set a feature value for a node.
`final FeatureBlockVector`	`rowVector(Integer nodeIndex)`	Create a lightweight RealVector view for a specific node, backed by this block.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FeatureBlock
```
FeatureBlock(Integer nodeCount, Integer dimension)
```
    Parameters:
    
    nodeCount - The total number of nodes in the document
    
    dimension - The number of features per node (e.g.
- Method Detail
  - getNodeCount
```
 final Integer getNodeCount()
```
  - getDimension
```
 final Integer getDimension()
```
  - get
```
 final Double get(Integer nodeIndex, Integer featureKey)
```
    Get a feature value for a node.
    
    Parameters:
    
    nodeIndex - The node's index in the document (0-based)
    
    featureKey - The feature key (0-based index into the feature vector)
    
    Returns:
    
    The feature value
  - set
```
 final Unit set(Integer nodeIndex, Integer featureKey, Double value)
```
    Set a feature value for a node.
    
    Parameters:
    
    nodeIndex - The node's index in the document (0-based)
    
    featureKey - The feature key (0-based index into the feature vector)
    
    value - The feature value to set
  - rowVector
```
 final FeatureBlockVector rowVector(Integer nodeIndex)
```
    Create a lightweight RealVector view for a specific node, backed by this block.
    
    Parameters:
    
    nodeIndex - The node's index in the document (0-based)
    
    Returns:
    
    A FeatureBlockVector that delegates get/set operations to this block