# sc::R12IntsAcc Class Reference

R12IntsAcc accumulates transformed (MO) integrals stored as (ijxy) where i, j, x, and, y lie in spaces I, J, X, and Y, respectively. More...

`#include <r12ia.h>`

Inheritance diagram for sc::R12IntsAcc:

List of all members.

## Public Types

enum | tbint_type { eri = 0, r12 = 1, r12t1 = 2, r12t2 = 3 }
| Types of two-body operators that R12IntsAcc understands.

## Public Member Functions

| R12IntsAcc (int num_te_types, int ni, int nj, int nx, int ny)
| R12IntsAcc (StateIn &)
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.
int | num_te_types () const
| The number of types of integrals that are being handled together.
int | ni () const
| Rank of index space i.
int | nj () const
| Rank of index space j.
int | nx () const
| Rank of index space x.
int | ny () const
| Rank of index space y.
size_t | blocksize () const
| Size of each block of the integrals of one type, in double words.
int | next_orbital () const
| The index of the first orbital in the next integrals batch to be stored.
virtual void | store_memorygrp (Ref< MemoryGrp > &mem, int ni, const size_t blksize=0)=0
| Stores all pair block of integrals held in mem in a layout assumed throughout MBPT2_R12.
virtual void | store_pair_block (int i, int j, double *ints)=0
| All member functions of this class and its children indices i and j don't include frozen orbitals Stores an ij pair block of integrals (assumes the block resides locally).
virtual void | commit ()
| Commit the content of the accumulator for reading.
bool | is_committed ()
| Has the content of the accumulator been commited for reading?
virtual void | activate ()
| Call before starting to read content.
virtual void | deactivate ()
| Call when done reading content.
const bool | is_active ()
| Check if can read content.
virtual double * | retrieve_pair_block (int i, int j, tbint_type oper_type)=0
| Retrieves an ij pair block of integrals.
virtual void | release_pair_block (int i, int j, tbint_type oper_type)=0
| Releases an ij pair block of integrals (if needed).
virtual bool | is_local (int i, int j) const =0
| Is this block stored locally?
virtual bool | is_avail (int i, int j) const =0
| Is this block available to this task?
virtual bool | has_access (int proc) const =0
| Does this task have access to all the integrals?
int | tasks_with_access (vector< int > &twa_map) const
| Returns the total number of tasks with access to integrals.
virtual bool | can_restart () const =0
| Can this specialization be used in restarts?

## Static Public Attributes

static const int | max_num_te_types_ = 4

## Protected Member Functions

virtual int | ntasks () const =0
| total number of tasks
virtual int | taskid () const =0
| ID of this task.
void | inc_next_orbital (int ni)
| The index of the first orbital in the next integrals batch to be stored.

## Protected Attributes

int | ni_
int | nj_
int | nx_
int | ny_
size_t | nxy_
size_t | blksize_
size_t | blocksize_
int | next_orbital_
bool | committed_
bool | active_

## Detailed Description

R12IntsAcc accumulates transformed (MO) integrals stored as (ijxy) where i, j, x, and, y lie in spaces I, J, X, and Y, respectively.

ijxy is only the storage format, the actual type may be (ix|jy), (ij|xy), etc.

Transformed integrals are usually computed using a parallel MO integrals transformation procedure. In general, such transformations will require multiple passes through AO integrals. Each pass produces a batch of transformed integrals. For example, a batch in direct parallel MP2 energy algorithm is a set of integrals {(ix|jy)} in which i indices are in a finite subrange of O and x, j, and y take any of their allowed values. For example, if batch I contains all integrals (ix|jy) with i greater than or equal m but less than n, then batch I+1 contains integrals (ix|jy) with i greater than n. Integrals in batch 0 have indices i greater than or equal to 0.

After each pass the MO integrals are contained in a MemoryGrp object. The object is "stored" in accumulator using `store_memorygrp(Ref<MemoryGrp>& mem, int ni)`. After all batches have been stored, the content of R12IntsAcc needs to be "committed" using `commit()`. After that blocks of MO integrals can be accessed using `retrieve_pair_block`.

## Member Function Documentation

void sc::R12IntsAcc::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::SavableState.

virtual void sc::R12IntsAcc::store_memorygrp | ( | Ref< MemoryGrp > & | mem,
|  | int | ni,
|  | const size_t | blksize = `0` |
| ) |  |  | `[pure virtual]`

Stores all pair block of integrals held in mem in a layout assumed throughout MBPT2_R12.

Let's suppose the number of tasks is nproc, nj is the number of j indices, ni is the number of i indices of integrals held in mem at the moment. Then all integrals with a given i and j are stored on task (i*nj+j)/nproc and this ij block is (i*nj+j)nproc -th block on this task. Each ij block contains num_te_types_ subblocks of integrals. Each subblock of integrals has blksize bytes allocated for it. Note that blksize may be larger than blksize_ because an ij-block of partially transformed integrals may be larger than the block of fully transformed integrals.

int sc::R12IntsAcc::tasks_with_access | ( | vector< int > & | twa_map | ) | const

Returns the total number of tasks with access to integrals.

If task i has access to the integrals, then twa_map[i] is its index among the tasks with access, -1 otherwise.

The documentation for this class was generated from the following file:

- r12ia.h