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The function returns zero.

14.5. Access to distributed array elements, allocated in remote element buffer.

Let r be the number of the distributed array dimensions, for which the linear sampling rule is not constant (the buffer rank). Then the header of remote element buffer, specified in the function crtrb_ call may be declared, for example, as

long BufferHeader[r+1];

Let the base pointer, corresponding to distributed array element type, be BasePtr. Then the access to allocated in the buffer element, determined by the index vector (V₁,... ,V_k, ... ,V_r), is performed by the linear index in the following way:

r-1

BasePtr[ ( BufferHeader[k]*V_k ) + V_r + BufferHeader[r] ] ,

k=1

where V_k is index variable of k-th not-constant sampling rule,

For C language the base pointer value can be equal to NULL in the function crtrb_ call. Then the access to the remote element allocated in the buffer can be performed as follows:

r-1

((Type *)BufferHeader[r])[ ( BufferHeader[k]*V_k ) + V_r] ,

k=1

where Type is the type of distributed array element.

The coefficients BufferHeader[1], ... ,BufferHeader[r-1] and the address constant BufferHeader[r] are calculated by Run-Time Library when executing the function crtrb_ in the following way.

Let:

Then:

r

BufferHeader[m] = ( LastIndexArray[I_k-1] - InitIndexArray[I_k-1]+1 ); (1  m  r-1)

k=m+1

r-1

BufferHeader[r] = -InitIndexArray[I_r-1] - ( BufferHeader[m] * InitIndexArray[I_m-1] );

m=1

Note. To access to the remote elements, allocated in the buffer, the functions and macros, considered in section 13, can be used. When using them, then

1. the buffer header is used instead of the distributed array header;

2. the array rank is supposed to be equal to the number of the array (the elements are located in the buffer) dimensions with non-constant sampling rules

3. the vector of index variable values of non-constant sampling rules is used as index vector of an element.

14.6. Creating group of remote element buffers.

The function crtbg_ creates empty buffer group (containing no buffers) and returns pointer to the group.

If the flag *StaticSignPtr of static group is not equal to zero, then the created group will not be deleted, when the control exits the program block (see section 8). Such group can be deleted only explicitly using the function delbg_ considered below.

If *DelBufSignPtr is not equal to zero, then all included in the group buffers will be deleted when the group is deleted. If deleting is explicit, all included buffers are deleted explicitly , and if deleting is implicit, they are deleted implicitly.

14.7. Including remote element buffer in the group.

The function returns zero.

14.8. Starting loading remote element buffers of specified group.

long loadbg_ (RegularAccessGroupRef *RegularAccessGroupRefPtr);

*RegularAccessGroupRefPtr - pointer to the buffer group.

The function returns zero.

14.9. Waiting for completion of loading remote element buffers of specified group.

long waitbg_ (RegularAccessGroupRef *RegularAccessGroupRefPtr);

*RegularAccessGroupRefPtr - pointer to the buffer group.

The function returns zero.

14.10. Deleting group of remote element buffers.

long delbg_ (RegularAccessGroupRef *RegularAccessGroupRefPtr);

*RegularAccessGroupRefPtr - a pointer to the buffer group to be deleted.

Non-static buffer group can be deleted by the function delbg_ only in the case if it was created in the current program block.

To delete the buffer group the function delobj_ can also be used (see section 17.5).

The function returns zero.

15. Non-regular access to remote data.

A scheme of non-regular access to the remote elements of distributed array is similar to scheme of the regular access, considered in section 14. But its application area is restricted by the arrays, having the only distributed dimension (all other dimensions are replicated). The remote elements, required in the current processor buffer, are specified by a set of the index vectors of the form:

{C₁} x ... x {C_k-1} x

U { ME[V_k,J+1] (~M: 0  J < ME[V_k,0] } x

V_k,init  V_k  V_k,last

{C_k+1} x ... x {C_n} ,

where:

The index matrix ME is the distributed array, with the first distributed dimension and the second replicated one (the segment [V_k,init, V_k,last] is the local part of the index matrix by the first dimension for the current processor). The size Size₂ of the second dimension of the matrix ME is equal to

MAX(ME[V_k,0]) + 1,

0  V_k < Size₁

where Size₁ - the size of its first dimension.

15.1. Creating remote element buffer of non-regular access.

The function crtib_ creates a buffer to allocate the remote elements of the distributed array with the header ArrayHeader, satisfying to remote access conditions.

The header BufferHeader of the created buffer is the array of 3 elements of "long" type. The buffer header allocation in memory (static or dynamic) is performed by a user program, but its initialization is performed by Run-Time Library when executing the function crtib_.

The base pointer BasePtr must refer to any variable of the same type as the type of the distributed array elements (the variable value is irrelevant).

In detail dealing with the header of remote elements buffer and the base pointer is considered in section 14.5.

If the flag *StaticSignPtr is not equal to zero, then the created buffer will not be deleted, when the control exits the a program block (see section 8). Such buffer can be deleted only explicitly using the function delib_ considered below.

The index matrix header MEHeader is the array of 3 elements of "long" type. When the function crtib_ is called, the index matrix and the distributed array must be allocated in the memory (mapped).

A value of ConstArray[k-1] is irrelevant (k is a number of the distributed dimension of the array with header ArrayHeader).

The function returns zero.

15.2. Starting loading remote element buffer of non-regular access.

long loadib_ (long BufferHeader[]);

BufferHeader - header of the remote element buffer of non-regular access.

The function loadib_ initializes loading specified buffer by the distributed array elements, for which the buffer was created by the function crtib_.

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