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

# sc\_ScaledTorsSimpleCo(3)

The ScaledTorsSimpleCo class describes an scaled torsion internal coordinate of a molecule.

## NAME

sc::ScaledTorsSimpleCo - The **ScaledTorsSimpleCo** class describes an scaled torsion internal coordinate of a molecule.

## SYNOPSIS

`#include <simple.h>`

Inherits **sc::SimpleCo**.

### Public Member Functions

**ScaledTorsSimpleCo** (const **ScaledTorsSimpleCo** &)\
 **ScaledTorsSimpleCo** (const char \*refr, int, int, int, int)\
 This constructor takes a string containing a label, and four integers a, b, c, and d which give the indices of the atoms involved in the torsion angle abcd.  **ScaledTorsSimpleCo** (const **Ref**\< **KeyVal** \> &)\
 The **KeyVal** constructor.  const char \* **ctype** () const\
 Always returns the string 'TORS'.  double **radians** () const\
 Returns the value of the angle abc in radians.  double **degrees** () const\
 Returns the value of the angle abc in degrees.  double **preferred\_value** () const\
 Returns the value of the angle abc in degrees.

### Additional Inherited Members

## Detailed Description

The **ScaledTorsSimpleCo** class describes an scaled torsion internal coordinate of a molecule.

The scaled torsion is more stable that ordinary torsions (see the **TorsSimpleCo** class) in describing situations where one of the torsions plane's is given by three near linear atoms.

Designating the four atoms as $a$, $b$, $c$, and $d$ and their cartesian positions as $$, $r{r}\_c$, and $lue of the coordinate, $ au\_s$, is given by

   \
                        { b}  imes r{n}\_{bcd}= ac{r{u}\_{cb}}\
                        { r{u}\_{cb} }\] \
     \
       \-1 & ox{if $(bc} imes\
                                   dot \
        1 & ox{otherwise}\
     \\nd{array}\
     ight. \] \
                         \
                    rccos ( - bc} dot

## Constructor & Destructor Documentation

### sc::ScaledTorsSimpleCo::ScaledTorsSimpleCo (const char \* refr, int, int, int, int)

This constructor takes a string containing a label, and four integers a, b, c, and d which give the indices of the atoms involved in the torsion angle abcd. Atom numbering begins at atom 1, not atom 0.

### sc::ScaledTorsSimpleCo::ScaledTorsSimpleCo (const Ref\< KeyVal \> &)

The **KeyVal** constructor. This calls the **SimpleCo** keyval constructor with an integer argument of 4.

## Member Function Documentation

### const char \* sc::ScaledTorsSimpleCo::ctype () const` [virtual]`

Always returns the string 'TORS'.

Implements **sc::IntCoor**.

### double sc::ScaledTorsSimpleCo::preferred\_value () const` [virtual]`

Returns the value of the angle abc in degrees.

Reimplemented from **sc::IntCoor**.

## Author

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