Visible to Intel only — GUID: GUID-9B94F678-4908-49B3-9A83-561FA31F7C15
Visible to Intel only — GUID: GUID-9B94F678-4908-49B3-9A83-561FA31F7C15
?lantr
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 matrix.
Syntax
val = slantr( norm, uplo, diag, m, n, a, lda, work )
val = dlantr( norm, uplo, diag, m, n, a, lda, work )
val = clantr( norm, uplo, diag, m, n, a, lda, work )
val = zlantr( norm, uplo, diag, m, n, a, lda, work )
Include Files
- mkl.fi
Description
The function ?lantr 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 matrix A.
Input Parameters
The data types are given for the Fortran interface.
- norm
-
CHARACTER*1. Specifies the value to be returned by the routine:
= 'M' or 'm': val = max(abs(Aij)), largest absolute value of the matrix A.
= '1' or 'O' or 'o': val = norm1(A), 1-norm of the matrix A (maximum column sum),
= 'I' or 'i': val = normI(A), infinity norm of the matrix A (maximum row sum),
= 'F', 'f', 'E' or 'e': val = normF(A), Frobenius norm of the matrix A (square root of sum of squares).
- uplo
-
CHARACTER*1.
Specifies whether the matrix A is upper or lower trapezoidal.
= 'U': Upper trapezoidal
= 'L': Lower trapezoidal.
Note that A is triangular instead of trapezoidal if m = n.
- diag
-
CHARACTER*1.
Specifies whether or not the matrix A has unit diagonal.
= 'N': Non-unit diagonal
= 'U': Unit diagonal.
- m
-
INTEGER. The number of rows of the matrix A. m≥ 0, and if uplo = 'U', m ≤ n.
When m = 0, ?lantr is set to zero.
- n
-
INTEGER. The number of columns of the matrix A. n≥ 0, and if uplo = 'L', n ≤ m.
When n = 0, ?lantr is set to zero.
- a
-
REAL for slantr
DOUBLE PRECISION for dlantr
COMPLEX for clantr
DOUBLE COMPLEX for zlantr
Array, DIMENSION (lda,n).
The trapezoidal matrix A (A is triangular if m = n).
If uplo = 'U', the leading m-by-n upper trapezoidal part of the array a contains the upper trapezoidal matrix, and the strictly lower triangular part of A is not referenced.
If uplo = 'L', the leading m-by-n lower trapezoidal part of the array a contains the lower trapezoidal matrix, and the strictly upper triangular part of A is not referenced. Note that when diag = 'U', the diagonal elements of A are not referenced and are assumed to be one.
- lda
-
INTEGER. The leading dimension of the array a.
lda≥ max(m,1).
- work
-
REAL for slantr/clantrp.
DOUBLE PRECISION for dlantr/zlantr.
Workspace array, DIMENSION(max(1,lwork)), where
lwork≥m when norm = 'I' ; otherwise, work is not referenced.
Output Parameters
- val
-
REAL for slantr/clantrp.
DOUBLE PRECISION for dlantr/zlantr.
Value returned by the function.