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

# sc\_TorsSimpleCo(3)

The TorsSimpleCo class describes an torsion internal coordinate of a molecule.

## NAME

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

## SYNOPSIS

`#include <simple.h>`

Inherits **sc::SimpleCo**.

### Public Member Functions

**TorsSimpleCo** (const **TorsSimpleCo** &)\
 **TorsSimpleCo** (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.  **TorsSimpleCo** (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 **TorsSimpleCo** class describes an torsion internal coordinate of a molecule.

The input is described in the documentation of its parent class **SimpleCo**.

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

   \
                        { b}  imes r{n}\_{bcd}= ac{r{u}\_{bc}}\
                        { r{u}\_{bc} } \] \
     \
         1 & ox{if $(bc} imesr{u}\_{cb}\
                   \> 0;$} \\\
        \-1 & ox{otherwise}\
     \\nd{array} ight.\
  \]

## Constructor & Destructor Documentation

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

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

## Member Function Documentation

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

Always returns the string 'TORS'.

Implements **sc::IntCoor**.

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

Returns the value of the angle abc in degrees.

Reimplemented from **sc::IntCoor**.

## Author

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