---
name: "sc_PowellUpdate"
section: "3"
platform: "linux"
package: "libsc-doc"
version: "2.3.1-22"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/sc_PowellUpdate"
---

# sc\_PowellUpdate(3)

The PowellUpdate class is used to specify a Powell hessian update.

## NAME

sc::PowellUpdate - The **PowellUpdate** class is used to specify a Powell hessian update.

## SYNOPSIS

`#include <update.h>`

Inherits **sc::HessianUpdate**.

### Public Member Functions

**PowellUpdate** (**StateIn** &)\
 **PowellUpdate** (const **Ref**\< **KeyVal** \> &)\
 void **save\_data\_state** (**StateOut** &)\
 Save the base classes (with save\_data\_state) and the members in the same order that the **StateIn** CTOR initializes them.  void **update** (const **RefSymmSCMatrix** &ihessian, const **Ref**\< **Function** \> &func, const **RefSCVector** &xnew, const **RefSCVector** &gnew)\
 void **apply\_transform** (const **Ref**\< **NonlinearTransform** \> &)\

### Protected Attributes

**RefSCVector** **xprev**\
 **RefSCVector** **gprev**\

### Additional Inherited Members

## Detailed Description

The **PowellUpdate** class is used to specify a Powell hessian update.

This hessian update method is the recommended method for use with transition state searches (the **EFCOpt** class can be used for transition state searches). \

## Member Function Documentation

### void sc::PowellUpdate::apply\_transform (const Ref\< NonlinearTransform \> &)` [virtual]`

Reimplemented from **sc::HessianUpdate**.

### void sc::PowellUpdate::save\_data\_state (StateOut &)` [virtual]`

Save the base classes (with save\_data\_state) and the members in the same order that the **StateIn** CTOR initializes them. This must be implemented by the derived class if the class has data.

Reimplemented from **sc::HessianUpdate**.

### void sc::PowellUpdate::update (const RefSymmSCMatrix & ihessian, const Ref\< Function \> & func, const RefSCVector & xnew, const RefSCVector & gnew)` [virtual]`

Implements **sc::HessianUpdate**.

## Author

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