p?lantr
p?lantr
Returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element, of a triangular matrix.
Syntax
float
pslantr
(
char
*norm
,
char
*uplo
,
char
*diag
,
MKL_INT
*m
,
MKL_INT
*n
,
float
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*work
);
double
pdlantr
(
char
*norm
,
char
*uplo
,
char
*diag
,
MKL_INT
*m
,
MKL_INT
*n
,
double
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
double
*work
);
float
pclantr
(
char
*norm
,
char
*uplo
,
char
*diag
,
MKL_INT
*m
,
MKL_INT
*n
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*work
);
double
pzlantr
(
char
*norm
,
char
*uplo
,
char
*diag
,
MKL_INT
*m
,
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?lantr
function
returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular distributed matrix sub(
= A
)
A
(ia
:ia
+m
-1ja
:ja
+n
-1)Input Parameters
- norm
- (global) Specifies what value is returned by thefunction:='M'or'm':, largest absolute value of the matrixval=max(abs(Aij))A, it s not a matrix norm.='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).
- uplo
- (global)Specifies whether the upper or lower triangular part of the symmetric matrix sub(A) is to be referenced.='U': Upper trapezoidal,='L': Lower trapezoidal.Note that sub(A) is triangular instead of trapezoidal if.m=n
- diag
- (global)Specifies whether the distributed matrix sub(A) has unit diagonal.='N': Non-unit diagonal.='U': Unit diagonal.
- m
- (global)The number of rows in the distributed matrix sub(A). When,m= 0p?lantris set to zero..m≥0
- n
- (global)The number of columns in the distributed matrix sub(A). When,n= 0p?lantris 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 sizelwork.iflwork≥0norm='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),,iroffa= 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 tool functions;myrow,mycol,nprow, andnpcolcan be determined by calling thefunctionblacs_gridinfo.
Output Parameters
- val
- The value returned by thefunction.