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PLAPACK calls

For the axpy, the calling sequences are given by place HR here

figure6509

figure6513

figure6516

place HR here The data type of the operands and parameters like vector length and stride are now passed as part of linear algebra objects alpha, x and y. Instead of returning the result as the function value, it is returned in alpha.

Local call:

When a node calls PLA_Local_dot, the operation is equivalent to extracting the local information (data type, length, and pointer to the buffers) and locally performing the inner product. The local dimensions of alpha must be tex2html_wrap_inline13895 , but it can be of any object type. The local dimensions of x, and y must be such that the operation is well-defined. All objects must have the same data type. Notice: no communication is performed as part of this call. Thus, all information must be locally available.

Global call:

All nodes must simultaneously call PLA_Dot, which performs the BLAS call on the distributed objects. Parameter alpha must be a tex2html_wrap_inline13897 multiscalar. Parameters x and y must be of object type vector or (duplicated) projected vector. The global dimensions of the different objects must be such that the operation is well-defined.


next up previous contents
Next: Norms of Vectors Up: Inner Product of Vectors Previous: PLAPACK FORTRAN-C interface

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