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

# sc\_StreSimpleCo(3)

The StreSimpleCo class describes an stretch internal coordinate of a molecule.

## NAME

sc::StreSimpleCo - The **StreSimpleCo** class describes an stretch internal coordinate of a molecule.

## SYNOPSIS

`#include <simple.h>`

Inherits **sc::SimpleCo**.

### Public Member Functions

**StreSimpleCo** (const **StreSimpleCo** &)\
 **StreSimpleCo** (const char \*, int, int)\
 This constructor takes a string containing a label, and two integers which are the indices of the atoms we're measuring the distance between.  **StreSimpleCo** (const **Ref**\< **KeyVal** \> &)\
 The **KeyVal** constructor.  const char \* **ctype** () const\
 Always returns the string 'STRE'.  double **bohr** () const\
 Returns the distance between the two atoms in atomic units.  double **angstrom** () const\
 Returns the distance between the two atoms in angstrom units.  double **preferred\_value** () const\
 Returns the distance between the two atoms in angstrom units.

### Additional Inherited Members

## Detailed Description

The **StreSimpleCo** class describes an stretch internal coordinate of a molecule.

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

Designating the two atoms as $a$ and $b$ and their cartesian positions as $$ and $lue of the coordinate, $r$, is

## Constructor & Destructor Documentation

### sc::StreSimpleCo::StreSimpleCo (const char \*, int, int)

This constructor takes a string containing a label, and two integers which are the indices of the atoms we're measuring the distance between. Atom numbering begins at atom 1, not atom 0.

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

The **KeyVal** constructor. This calls the **SimpleCo** keyval constructor with an integer argument of 2.

## Member Function Documentation

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

Always returns the string 'STRE'.

Implements **sc::IntCoor**.

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

Returns the distance between the two atoms in angstrom units.

Reimplemented from **sc::IntCoor**.

## Author

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