---
name: "mlpack_optimization_test_GeneralizedRosenbrockFunction"
section: "3"
platform: "linux"
package: "mlpack-doc"
version: "1.0.10-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/mlpack_optimization_test_GeneralizedRosenbrockFunction"
---

# mlpack\_optimization\_test\_GeneralizedRosenbrockFunction(3)

The Generalized Rosenbrock function in n dimensions, defined by f(x) = sum\_i^{n - 1} (f(i)(x)) f\_i(x) = 100 \* (x\_i^2 - x\_{i + 1})^2 + (1 - x\_i)^2 x\_0 = \[-1.2, 1, -1.2, 1, ...\].

## NAME

mlpack::optimization::test::GeneralizedRosenbrockFunction -

The Generalized Rosenbrock function in n dimensions, defined by f(x) = sum\_i^{n - 1} (f(i)(x)) f\_i(x) = 100 \* (x\_i^2 - x\_{i + 1})^2 + (1 - x\_i)^2 x\_0 = \[-1.2, 1, -1.2, 1, ...\].

## SYNOPSIS

### Public Member Functions

**GeneralizedRosenbrockFunction** (int **n**)\
 double **Evaluate** (const arma::mat &coordinates) const \
 double **Evaluate** (const arma::mat &coordinates, const size\_t i) const \
 const arma::mat & **GetInitialPoint** () const \
 void **Gradient** (const arma::mat &coordinates, arma::mat &gradient) const \
 void **Gradient** (const arma::mat &coordinates, const size\_t i, arma::mat &gradient) const \
 size\_t **NumFunctions** () const \

### Private Attributes

arma::mat **initialPoint**\
 int **n**\

## Detailed Description

The Generalized Rosenbrock function in n dimensions, defined by f(x) = sum\_i^{n - 1} (f(i)(x)) f\_i(x) = 100 \* (x\_i^2 - x\_{i + 1})^2 + (1 - x\_i)^2 x\_0 = \[-1.2, 1, -1.2, 1, ...\].

This should optimize to f(x) = 0, at x = \[1, 1, 1, 1, ...\].

This function can also be used for stochastic gradient descent (**SGD**) as a decomposable function (DecomposableFunctionType), so there are other overloads of **Evaluate()** and **Gradient()** implemented, as well as **NumFunctions()**.

Definition at line 123 of file test\_functions.hpp.

## Constructor & Destructor Documentation

### mlpack::optimization::test::GeneralizedRosenbrockFunction::GeneralizedRosenbrockFunction (intn)

## Member Function Documentation

### double mlpack::optimization::test::GeneralizedRosenbrockFunction::Evaluate (const arma::mat &coordinates) const

### double mlpack::optimization::test::GeneralizedRosenbrockFunction::Evaluate (const arma::mat &coordinates, const size\_ti) const

### const arma::mat& mlpack::optimization::test::GeneralizedRosenbrockFunction::GetInitialPoint () const

### void mlpack::optimization::test::GeneralizedRosenbrockFunction::Gradient (const arma::mat &coordinates, arma::mat &gradient) const

### void mlpack::optimization::test::GeneralizedRosenbrockFunction::Gradient (const arma::mat &coordinates, const size\_ti, arma::mat &gradient) const

### size\_t mlpack::optimization::test::GeneralizedRosenbrockFunction::NumFunctions () const` [inline]`

Definition at line 136 of file test\_functions.hpp.

## Member Data Documentation

### arma::mat mlpack::optimization::test::GeneralizedRosenbrockFunction::initialPoint` [private]`

Definition at line 145 of file test\_functions.hpp.

### int mlpack::optimization::test::GeneralizedRosenbrockFunction::n` [private]`

Definition at line 146 of file test\_functions.hpp.

## Author

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