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PLAPACK calls

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

figure6586

figure6590

figure6593

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 x, xmax, and k. Instead of returning the result k as the function value, it is returned in k. In addition, the value of x(k) is returned.

Local call:

When a node calls PLA_Local_iamax the operation is equivalent to extracting the local information (data type, length, and pointer to the buffers) and locally performing the appropriate operation. The local dimensions of xmax and k must be tex2html_wrap_inline13992 , but they can be of any object type. The data type of k must be integer (MPI_INT). The local dimensions of x 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_Iamax, which performs the BLAS call on the distributed objects. Parameters xmax and k must be tex2html_wrap_inline13994 multiscalars. The datatype of k must be integer. Parameter x must be of object type vector or (duplicated) projected vector.


next up previous contents
Next: Example: Parallelizing Inner Product Up: Maximum Absolute Value in Previous: PLAPACK FORTRAN-C interface

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