HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 4 Sparse BLAS Operations 437
What you need to know to use these subprograms
• bpntrb(*) - Integer array of length mb such that bpntrb(j) points to location
in bindx(*) of the first nonzero block in block row j.
• bpntre(*) - Integer array of length mb such that pntre(j)-1 points to location
bindx(*) of the last nonzero block in block row j.
Consider, for example, the 6 x 6 matrix:
Table 4-20 6 x 6 Matrix
This matrix could be represented in VBR format using a 2x1x3 blocking:
Table 4-21 VBR Format Matrix
Operator arguments in the Sparse BLAS
The argument conventions follow the spirit of the dense BLAS.
• Point entry matrix-matrix product:
XYYYMM (TRANSA, M, N, K, ALPHA, args(A), B, LDB, BETA, C, LDC,
WORK, LWORK)
• Block entry matrix-matrix product:
XYYYMM (TRANSA, MB, N, KB, ALPHA, args(A), B, BLDB, BETA, C,
BLDC, WORK, LWORK)
• Point entry solution of triangular system:
11 12 0 14 15 16
21 22 0 24 25 26
31 32 33 0 0 0
0 0 43 44 0 0
0 0 53 54 55 0
0 0 63 64 65 66
val= 11 21 12 22 14 24 15 25 16
26 31 32 33 43 53 63 44 54
64 85565 0 066
indx= 1 5 11 13 14 17 26
bindx= 131223
rpntr= 1347
cpntr= 1347
bpntbr= 135
bpntbe= 357