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

Chapter 9 LAPACK Auxiliary Subprograms 671
Compute norm of symmetric or Hermitian packed matrix SLANSP/DLANSP/CLANHP/CLANSP/.../ZLANSP
Name SLANSP/DLANSP/CLANHP/CLANSP/.../ZLANSP
Compute norm of symmetric or Hermitian packed matrix
Purpose These subprograms compute a norm of a real or complex symmetric or complex
Hermitian matrix A that is stored in an array in packed form.
A matrix is symmetric if A = A
T
, its transpose; a matrix is Hermitian if
A = A*, its conjugate transpose.
The structure of A is indicated by the name of the subprogram used:
Matrix
Storage
Because either triangle of A may be obtained from the other, you need only
provide one triangle of A, either the upper or the lower triangle. Compared to
storing the entire matrix, you save memory by supplying that triangle stored
column-by-column in packed form in a 1-dimensional array.
The following examples illustrate the packed storage of symmetric or
Hermitian matrices.
Upper triangular storage
If the upper triangle of A is
then A is packed column-by-column into an array ap as follows:
Upper triangular matrix element a
ij
is stored in array element ap(i+(j×(j−1))/2).
SLANSP or DLANSP A is a real symmetric packed matrix.
CLANSP or ZLANSP A is a complex symmetric packed matrix.
CLANHP or ZLANHP A is a complex Hermitian packed matrix.
11 12 13 14
22 23 24
33 34
44
k 12345678910
ap(k) 11122213233314243444