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# List of Notation

    1D 		 One-dimensional (as in 1D data distribution)

     		 Bandwidth (or throughput) for the network

    2D 		 Two-dimensional (as in 2D data distribution)

     		 Total number of floating-point operations

     		 Total number of messages

    CSRC_ Entry in DESC_ indicating the process column over which

            		 the first column of the array is distributed

    CTXT_ Entry in DESC_ indicating the BLACS context associated with the

            		 global array

     		 Total number of data items communicated

    DESC_ Array descriptor for a global array

    DESCA  		 Array descriptor for global array A

    DESCB  		 Array descriptor for global array B

    DLEN_ Length of the descriptor DESC_

    DTYPE_ First entry of the descriptor DESC_, identifying

            		 the descriptor type

    E()   		 Estimated parallel efficiency

     		 Time per floating point operation in matrix-matrix multiply

    Gflop/s 		 Gigaflops ( floating point operations) per second

    IA     		 Global row index in the global array A indicating the

           		 first row of

    ICTXT 		 BLACS context associated with a process grid

    INFO 		 Output integer argument of driver and computational routines

         		 indicating the success or failure of the routine

    JA     		 Global column index in the global array A indicating the

           		 first column of

     		 Least common multiple of ()

    LLD_ Entry in DESC_ indicating the local leading dimension of the

          		 local array

     		 Local leading dimension of the local array A

     		 Local leading dimension of the local array B

    (K_) 		 Number of columns that a process receives if  columns

                   		 of a matrix are distributed over c columns of its process row.

    (K_) 		 Number of rows that a process would receive if  rows

                   		 of a matrix are distributed over r rows of its process column.

    M     		 Global number of rows of the distributed submatrix

    M_ Entry of DESC_ indicating the number of rows in the global

          		 array

    MB    		 Global row block size for partitioning the global matrix

    MB_ Entry in DESC_ indicating the block size used to distribute

          		 the rows of the global array

    MB/s 		 Megabyte per second

    Mflop/s 		 Megaflops ( floating point operations) per second

    MYCOL  		 The calling process's column coordinate in the process grid.

    MYROW  		 The calling process's row coordinate in the process grid

    N     		 Global number of columns of the distributed submatrix

    N_ Entry of DESC_ indicating the number of columns in the

          		 global array

    NB    		 Global column block size for partitioning the global matrix

    NB_ Entry in DESC_ indicating the block size used to distribute

          		 the columns of the global array

    NBRHS 		 Global column block size for the solution matrix

    NPCOL  		 Number of process columns in the process grid (equivalent to )

    NPROCS 		 Total number of processes in the process grid (equivalent to P)

    NPROW  		 Number of process rows in the process grid (equivalent to )

    NRHS  		 Global number of columns in the global solution matrix B

    NUMROC 		 TOOLS routine used to calculate the number of rows or columns

           		 in a local array

    P     		 Total number of processes in the process grid, i.e.,

     		 Number of process columns in the process grid

     		 Number of process rows in the process grid

    RSRC_ Entry in DESC_ indicating the process row over which the

            		 first row of the array is distributed

     		 Distributed submatrix A(IA:IA+M-1,JA:JA+N-1)

    T()   		 Estimated parallel execution time

    () 		 Estimated serial execution time

     		 Time per floating-point operation (typically )

     		 Time per message (latency)

     		 Time required to solve a problem of size N on P processors

     		 Time required to solve a problem of size N/2 on P processors

     		 Time per data item communicated

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