1DLANST(1) LAPACK auxiliary routine (version 3.2) DLANST(1)
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6 DLANST - returns the value of the one norm, or the Frobenius norm, or
7 the infinity norm, or the element of largest absolute value of a real
8 symmetric tridiagonal matrix A
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11 DOUBLE PRECISION FUNCTION DLANST( NORM, N, D, E )
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13 CHARACTER NORM
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15 INTEGER N
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17 DOUBLE PRECISION D( * ), E( * )
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20 DLANST returns the value of the one norm, or the Frobenius norm, or
21 the infinity norm, or the element of largest absolute value of a
22 real symmetric tridiagonal matrix A.
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25 DLANST returns the value
26 DLANST = ( max(abs(A(i,j))), NORM = 'M' or 'm'
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28 ( norm1(A), NORM = '1', 'O' or 'o'
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30 ( normI(A), NORM = 'I' or 'i'
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32 ( normF(A), NORM = 'F', 'f', 'E' or 'e' where
33 norm1 denotes the one norm of a matrix (maximum column sum), normI
34 denotes the infinity norm of a matrix (maximum row sum) and normF
35 denotes the Frobenius norm of a matrix (square root of sum of
36 squares). Note that max(abs(A(i,j))) is not a consistent matrix
37 norm.
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40 NORM (input) CHARACTER*1
41 Specifies the value to be returned in DLANST as described
42 above.
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44 N (input) INTEGER
45 The order of the matrix A. N >= 0. When N = 0, DLANST is set
46 to zero.
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48 D (input) DOUBLE PRECISION array, dimension (N)
49 The diagonal elements of A.
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51 E (input) DOUBLE PRECISION array, dimension (N-1)
52 The (n-1) sub-diagonal or super-diagonal elements of A.
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56 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008 DLANST(1)