p?lanhs
p?lanhs
Returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element, of an upper Hessenberg matrix.
Syntax
float
pslanhs
(
char
*norm
,
MKL_INT
*n
,
float
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*work
);
double
pdlanhs
(
char
*norm
,
MKL_INT
*n
,
double
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
double
*work
);
float
pclanhs
(
char
*norm
,
MKL_INT
*n
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*work
);
double
pzlanhs
(
char
*norm
,
MKL_INT
*n
,
MKL_Complex16
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
double
*work
);
Include Files
- mkl_scalapack.h
Description
The
p?lanhs
function
returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of an upper Hessenberg distributed matrix sub(
.A
) = A
(ia:ia+m-1
, ja:ja+n-1
)Input Parameters
- norm
- Specifies the value to be returned by thefunction:='M'or'm':, largest absolute value of the matrixval=max(abs(Aij))A.='1'or'O'or'o':, 1-norm of the matrixval=norm1(A)A(maximum column sum),='I'or'i':, infinity norm of the matrixval=normI(A)A(maximum row sum),='F','f','E'or'e':, Frobenius norm of the matrixval=normF(A)A(square root of sum of squares).
- n
- The number of columns in the distributed matrix sub((global)A). Whenn= 0,p?lanhsis set to zero.n≥0.
- a
- (local).Pointer into the local memory to an array of sizecontaining the local pieces of the distributed matrix sub(*lld_aLOCc(ja+n-1)A).
- ia,ja
- (global)The row and column indices in the global matrixAindicating the first row and the first column of the matrix sub(A), respectively.
- desca
- (global and local) array of sizedlen_. The array descriptor for the distributed matrix A.
- work
- (local).Array of sizelwork.lwork≥0 ifnorm='M'or'm'(not referenced),nq0 ifnorm= '1','O'or'o',mp0 ifnorm='I'or'i',0 if,norm='F''f','E'or'e'(not referenced),whereiroffa=mod(ia-1,mb_a),icoffa=mod(ja-1,nb_a),iarow=indxg2p(ia,mb_a,myrow,rsrc_a,nprow),iacol=indxg2p(ja,nb_a,mycol,csrc_a,npcol),mp0 =numroc(m+iroffa,mb_a,myrow,iarow,nprow),nq0 =numroc(n+icoffa,nb_a,mycol,iacol,npcol),indxg2pandnumrocare ScaLAPACK toolfunctions;myrow,imycol,nprow, andnpcolcan be determined by calling thefunctionblacs_gridinfo.
Output Parameters
- val
- The value returned by the function.