3 * =========== DOCUMENTATION ===========
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
11 * DOUBLE PRECISION FUNCTION DSXT1( IJOB, D1, N1, D2, N2, ABSTOL,
14 * .. Scalar Arguments ..
15 * INTEGER IJOB, N1, N2
16 * DOUBLE PRECISION ABSTOL, ULP, UNFL
18 * .. Array Arguments ..
19 * DOUBLE PRECISION D1( * ), D2( * )
28 *> DSXT1 computes the difference between a set of eigenvalues.
29 *> The result is returned as the function value.
31 *> IJOB = 1: Computes max { min | D1(i)-D2(j) | }
34 *> IJOB = 2: Computes max { min | D1(i)-D2(j) | /
36 *> ( ABSTOL + |D1(i)|*ULP ) }
45 *> Specifies the type of tests to be performed. (See above.)
50 *> D1 is DOUBLE PRECISION array, dimension (N1)
51 *> The first array. D1 should be in increasing order, i.e.,
63 *> D2 is DOUBLE PRECISION array, dimension (N2)
64 *> The second array. D2 should be in increasing order, i.e.,
76 *> ABSTOL is DOUBLE PRECISION
77 *> The absolute tolerance, used as a measure of the error.
82 *> ULP is DOUBLE PRECISION
88 *> UNFL is DOUBLE PRECISION
89 *> The smallest positive number whose reciprocal does not
96 *> \author Univ. of Tennessee
97 *> \author Univ. of California Berkeley
98 *> \author Univ. of Colorado Denver
101 *> \date November 2011
103 *> \ingroup double_eig
105 * =====================================================================
106 DOUBLE PRECISION FUNCTION DSXT1( IJOB, D1, N1, D2, N2, ABSTOL,
109 * -- LAPACK test routine (version 3.4.0) --
110 * -- LAPACK is a software package provided by Univ. of Tennessee, --
111 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
114 * .. Scalar Arguments ..
116 DOUBLE PRECISION ABSTOL, ULP, UNFL
118 * .. Array Arguments ..
119 DOUBLE PRECISION D1( * ), D2( * )
122 * =====================================================================
125 DOUBLE PRECISION ZERO
126 PARAMETER ( ZERO = 0.0D0 )
128 * .. Local Scalars ..
130 DOUBLE PRECISION TEMP1, TEMP2
132 * .. Intrinsic Functions ..
133 INTRINSIC ABS, MAX, MIN
135 * .. Executable Statements ..
142 IF( D2( J ).LT.D1( I ) .AND. J.LT.N2 ) THEN
147 TEMP2 = ABS( D2( J )-D1( I ) )
149 $ TEMP2 = TEMP2 / MAX( UNFL, ABSTOL+ULP*ABS( D1( I ) ) )
151 TEMP2 = MIN( ABS( D2( J )-D1( I ) ),
152 $ ABS( D1( I )-D2( J-1 ) ) )
154 $ TEMP2 = TEMP2 / MAX( UNFL, ABSTOL+ULP*ABS( D1( I ) ) )
156 TEMP1 = MAX( TEMP1, TEMP2 )