slangt.f - Man Page
SRC/slangt.f
Synopsis
Functions/Subroutines
real function slangt (norm, n, dl, d, du)
SLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix.
Function/Subroutine Documentation
real function slangt (character norm, integer n, real, dimension( * ) dl, real, dimension( * ) d, real, dimension( * ) du)
SLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix.
Purpose:
SLANGT returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real tridiagonal matrix A.
- Returns
SLANGT
SLANGT = ( max(abs(A(i,j))), NORM = 'M' or 'm' ( ( norm1(A), NORM = '1', 'O' or 'o' ( ( normI(A), NORM = 'I' or 'i' ( ( normF(A), NORM = 'F', 'f', 'E' or 'e' where norm1 denotes the one norm of a matrix (maximum column sum), normI denotes the infinity norm of a matrix (maximum row sum) and normF denotes the Frobenius norm of a matrix (square root of sum of squares). Note that max(abs(A(i,j))) is not a consistent matrix norm.
- Parameters
NORM
NORM is CHARACTER*1 Specifies the value to be returned in SLANGT as described above.
N
N is INTEGER The order of the matrix A. N >= 0. When N = 0, SLANGT is set to zero.
DL
DL is REAL array, dimension (N-1) The (n-1) sub-diagonal elements of A.
D
D is REAL array, dimension (N) The diagonal elements of A.
DU
DU is REAL array, dimension (N-1) The (n-1) super-diagonal elements of A.
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 105 of file slangt.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page slangt(3) is an alias of slangt.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK