# QuantLib_Tree man page

Tree< T > — Tree approximating a single-factor diffusion

## Synopsis

`#include <ql/methods/lattices/tree.hpp>`

Inherits **CuriouslyRecurringTemplate< T >**.

Inherited by **BinomialTree< T >**, and **ExtendedBinomialTree< T >**.

### Public Member Functions

Tree(Sizecolumns)Size columns() const

### Additional Inherited Members

## Detailed Description

### template<class T>

class QuantLib::Tree< T >" Tree approximating a single-factor diffusion

Derived classes must implement the following interface:

```
public:
Real underlying(Size i, Size index) const;
Size size(Size i) const;
Size descendant(Size i, Size index, Size branch) const;
Real probability(Size i, Size index, Size branch) const;
```

and provide a public enumeration

`enum { branches = N };`

where N is a suitable constant (2 for binomial, 3 for trinomial...)

## Author

Generated automatically by Doxygen for QuantLib from the source code.

## Referenced By

Tree(3) is an alias of QuantLib_Tree(3).