HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 9 LAPACK Auxiliary Subprograms 659
Compute norm of general band matrix SLANGB/DLANGB/CLANGB/ZLANGB
CHARACTER*1 norm
INTEGER*8 kl, ku, ldab, n
REAL*4 rwork(n)
COMPLEX*8 ab(ldab, n)
REAL*4 anorm, CLANGB
anorm = CLANGB(norm, n, kl, ku, ab, ldab, rwork)
CHARACTER*1 norm
INTEGER*8 kl, ku, ldab, n
REAL*8 rwork(n)
COMPLEX*16 ab(ldab, n)
REAL*8 anorm, ZLANGB
anorm = ZLANGB(norm, n, kl, ku, ab, ldab, rwork)
Input norm Specifies which norm is to be computed, as follows:
norm = ’F’, ’f’, ’E’, or ’e’ Compute ||A||
F
= the Frobenius
norm.
norm = ’I’ or ’i’: Compute ||A||
∞
= maximum
row sum.
norm = ’1’, ’O’, or ’o’ Compute ||A||
1
= maximum
column sum.
norm = ’M’ or ’m’ Compute max(|A
ij
|).
n The order of the matrix A. n ≥ 0.
kl The number of subdiagonals within the band of A.
kl ≥ 0.
ku The number of superdiagonals within the band of A.
ku ≥ 0.
ab The matrix A in band storage, in the first kl+ku+1
rows. The j-th column of A is stored in the j-th column
of array ab as follows: ab(ku+1+i−j,j) = A(i,j) for
max(1,j−ku) ≤ i ≤ min(n,j+kl)
ldab The leading dimension of array ab in the calling
program unit. ldab ≥ kl+ku+1.
Working
Storage
work,
rwork
Arrays used for work space. Not referenced unless
norm = ’I’ or ’i’.