LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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◆ sget10()

subroutine sget10 ( integer  M,
integer  N,
real, dimension( lda, * )  A,
integer  LDA,
real, dimension( ldb, * )  B,
integer  LDB,
real, dimension( * )  WORK,
real  RESULT 
)

SGET10

Purpose:
 SGET10 compares two matrices A and B and computes the ratio
 RESULT = norm( A - B ) / ( norm(A) * M * EPS )
Parameters
[in]M
          M is INTEGER
          The number of rows of the matrices A and B.
[in]N
          N is INTEGER
          The number of columns of the matrices A and B.
[in]A
          A is REAL array, dimension (LDA,N)
          The m by n matrix A.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,M).
[in]B
          B is REAL array, dimension (LDB,N)
          The m by n matrix B.
[in]LDB
          LDB is INTEGER
          The leading dimension of the array B.  LDB >= max(1,M).
[out]WORK
          WORK is REAL array, dimension (M)
[out]RESULT
          RESULT is REAL
          RESULT = norm( A - B ) / ( norm(A) * M * EPS )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 92 of file sget10.f.

93*
94* -- LAPACK test routine --
95* -- LAPACK is a software package provided by Univ. of Tennessee, --
96* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
97*
98* .. Scalar Arguments ..
99 INTEGER LDA, LDB, M, N
100 REAL RESULT
101* ..
102* .. Array Arguments ..
103 REAL A( LDA, * ), B( LDB, * ), WORK( * )
104* ..
105*
106* =====================================================================
107*
108* .. Parameters ..
109 REAL ONE, ZERO
110 parameter( one = 1.0e+0, zero = 0.0e+0 )
111* ..
112* .. Local Scalars ..
113 INTEGER J
114 REAL ANORM, EPS, UNFL, WNORM
115* ..
116* .. External Functions ..
117 REAL SASUM, SLAMCH, SLANGE
118 EXTERNAL sasum, slamch, slange
119* ..
120* .. External Subroutines ..
121 EXTERNAL saxpy, scopy
122* ..
123* .. Intrinsic Functions ..
124 INTRINSIC max, min, real
125* ..
126* .. Executable Statements ..
127*
128* Quick return if possible
129*
130 IF( m.LE.0 .OR. n.LE.0 ) THEN
131 result = zero
132 RETURN
133 END IF
134*
135 unfl = slamch( 'Safe minimum' )
136 eps = slamch( 'Precision' )
137*
138 wnorm = zero
139 DO 10 j = 1, n
140 CALL scopy( m, a( 1, j ), 1, work, 1 )
141 CALL saxpy( m, -one, b( 1, j ), 1, work, 1 )
142 wnorm = max( wnorm, sasum( n, work, 1 ) )
143 10 CONTINUE
144*
145 anorm = max( slange( '1', m, n, a, lda, work ), unfl )
146*
147 IF( anorm.GT.wnorm ) THEN
148 result = ( wnorm / anorm ) / ( m*eps )
149 ELSE
150 IF( anorm.LT.one ) THEN
151 result = ( min( wnorm, m*anorm ) / anorm ) / ( m*eps )
152 ELSE
153 result = min( wnorm / anorm, real( m ) ) / ( m*eps )
154 END IF
155 END IF
156*
157 RETURN
158*
159* End of SGET10
160*
real function slange(NORM, M, N, A, LDA, WORK)
SLANGE returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value ...
Definition: slange.f:114
subroutine scopy(N, SX, INCX, SY, INCY)
SCOPY
Definition: scopy.f:82
subroutine saxpy(N, SA, SX, INCX, SY, INCY)
SAXPY
Definition: saxpy.f:89
real function sasum(N, SX, INCX)
SASUM
Definition: sasum.f:72
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:68
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