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

# sc\_SpatialMOPairIter\_eq(3)

SpatialMOPairIter\_eq gives the ordering of same-spin and different-spin orbital pairs if both orbitals of the pairs are from the same space.

## NAME

sc::SpatialMOPairIter\_eq - **SpatialMOPairIter\_eq** gives the ordering of same-spin and different-spin orbital pairs if both orbitals of the pairs are from the same space.

## SYNOPSIS

`#include <pairiter.h>`

Inherits **sc::SpatialMOPairIter**.

### Public Member Functions

**SpatialMOPairIter\_eq** (const **Ref**\< **MOIndexSpace** \> &space1)\
 Initialize an iterator for the given MO spaces.  void **start** (const int ij\_offset=0)\
 Initialize the iterator assuming that iteration will start with pair ij\_offset.  void **next** ()\
 Move to the next pair.  **operator int** () const\
 Returns nonzero if the iterator currently hold valid data.  int **nij\_aa** () const\
 Returns the number of functions in alpha-alpha space.  int **nij\_ab** () const\
 Returns the number of functions in alpha-beta space.  int **ij\_aa** () const\
 Returns compound index ij for alpha-alpha case.  int **ij\_ab** () const\
 Returns compound index ij for alpha-beta case.  int **ij\_ba** () const\
 Returns compound index ij for beta-alpha case.

### Additional Inherited Members

## Detailed Description

**SpatialMOPairIter\_eq** gives the ordering of same-spin and different-spin orbital pairs if both orbitals of the pairs are from the same space.

It iterates over all i \>= j combinations (total of (ni\_+1)\*(ni\_+2)/2 pairs).

## Member Function Documentation

### int sc::SpatialMOPairIter\_eq::ij\_aa () const` [inline]`, ` [virtual]`

Returns compound index ij for alpha-alpha case. The i == j combination doesn't make sense, so **ij\_aa()** will return -1 for such pairs.

Implements **sc::SpatialMOPairIter**.

### int sc::SpatialMOPairIter\_eq::ij\_ab () const` [inline]`, ` [virtual]`

Returns compound index ij for alpha-beta case.

Implements **sc::SpatialMOPairIter**.

### int sc::SpatialMOPairIter\_eq::ij\_ba () const` [inline]`, ` [virtual]`

Returns compound index ij for beta-alpha case.

Implements **sc::SpatialMOPairIter**.

### void sc::SpatialMOPairIter\_eq::next ()` [inline]`, ` [virtual]`

Move to the next pair.

Implements **sc::MOPairIter**.

### int sc::SpatialMOPairIter\_eq::nij\_aa () const` [inline]`, ` [virtual]`

Returns the number of functions in alpha-alpha space.

Implements **sc::SpatialMOPairIter**.

### int sc::SpatialMOPairIter\_eq::nij\_ab () const` [inline]`, ` [virtual]`

Returns the number of functions in alpha-beta space.

Implements **sc::SpatialMOPairIter**.

### sc::SpatialMOPairIter\_eq::operator int () const` [inline]`, ` [virtual]`

Returns nonzero if the iterator currently hold valid data.

Implements **sc::MOPairIter**.

### void sc::SpatialMOPairIter\_eq::start (const int ij\_offset = `0`)` [inline]`, ` [virtual]`

Initialize the iterator assuming that iteration will start with pair ij\_offset.

Implements **sc::MOPairIter**.

## Author

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