GNU/Linux |
CentOS 4.8 |
i386 |
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clangt(l) |
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CLANGT - return the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex tridiagonal matrix A
REAL FUNCTION |
CLANGT( NORM, N, DL, D, DU ) |
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CHARACTER |
NORM |
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INTEGER |
N |
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COMPLEX |
D( * ), DL( * ), DU( * ) |
CLANGT returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex tridiagonal matrix A.
CLANGT returns the value
CLANGT = (
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 matrix norm.
NORM (input) CHARACTER*1
Specifies the value to be returned in CLANGT as described above.
N (input) INTEGER
The order of the matrix A. N >= 0. When N = 0, CLANGT is set to zero.
DL (input) COMPLEX array, dimension (N-1)
The (n-1) sub-diagonal elements of A.
D (input) COMPLEX array, dimension (N)
The diagonal elements of A.
DU (input) COMPLEX array, dimension (N-1)
The (n-1) super-diagonal elements of A.
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