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PLAPACK calls

For the symmetric rank-2 update, the calling sequences are given by place HR here

figure8085

figure8089

figure8092

place HR here Parameter UPLO has been replaced by integer uplo, which can take on the values indicated in Table gif. All other parameters are now passed as part of linear algebra objects alpha, a, x, and y.

Local call:

When a node calls PLA_Local_syr2, the operation is equivalent to extracting the local information (datatype, dimensions, and pointer to the buffer) and locally performing the symmetric rank-2 update. The local dimensions of alpha must be tex2html_wrap_inline14517 , but it can be of any object type. The local dimensions of a and the lengths of x and y must be such that the operation is well-defined. All objects must have the same datatype. 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_Syr2, which performs the BLAS call on the distributed objects. Parameter uplo still has the same meaning. Parameter alpha must be a tex2html_wrap_inline14519 multiscalar. Parameter a must be of object type matrix. Parameters x and y must both be of a vector object type, including vector, projected 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: Example: Parallelizing Matrix-Vector Multiplication Up: Symmetric Rank-2 Update Previous: PLAPACK FORTRAN-C interface

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