LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ dlag2s()

subroutine dlag2s ( integer  m,
integer  n,
double precision, dimension( lda, * )  a,
integer  lda,
real, dimension( ldsa, * )  sa,
integer  ldsa,
integer  info 
)

DLAG2S converts a double precision matrix to a single precision matrix.

Download DLAG2S + dependencies [TGZ] [ZIP] [TXT]

Purpose:
 DLAG2S converts a DOUBLE PRECISION matrix, A, to a SINGLE
 PRECISION matrix, SA.

 RMAX is the overflow for the SINGLE PRECISION arithmetic
 DLAG2S checks that all the entries of A are between -RMAX and
 RMAX. If not the conversion is aborted and a flag is raised.

 This is an auxiliary routine so there is no argument checking.
Parameters
[in]M
          M is INTEGER
          The number of lines of the matrix A.  M >= 0.
[in]N
          N is INTEGER
          The number of columns of the matrix A.  N >= 0.
[in]A
          A is DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the M-by-N coefficient matrix A.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,M).
[out]SA
          SA is REAL array, dimension (LDSA,N)
          On exit, if INFO=0, the M-by-N coefficient matrix SA; if
          INFO>0, the content of SA is unspecified.
[in]LDSA
          LDSA is INTEGER
          The leading dimension of the array SA.  LDSA >= max(1,M).
[out]INFO
          INFO is INTEGER
          = 0:  successful exit.
          = 1:  an entry of the matrix A is greater than the SINGLE
                PRECISION overflow threshold, in this case, the content
                of SA in exit is unspecified.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 107 of file dlag2s.f.

108*
109* -- LAPACK auxiliary routine --
110* -- LAPACK is a software package provided by Univ. of Tennessee, --
111* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
112*
113* .. Scalar Arguments ..
114 INTEGER INFO, LDA, LDSA, M, N
115* ..
116* .. Array Arguments ..
117 REAL SA( LDSA, * )
118 DOUBLE PRECISION A( LDA, * )
119* ..
120*
121* =====================================================================
122*
123* .. Local Scalars ..
124 INTEGER I, J
125 DOUBLE PRECISION RMAX
126* ..
127* .. External Functions ..
128 REAL SLAMCH
129 EXTERNAL slamch
130* ..
131* .. Intrinsic Functions ..
132 INTRINSIC real
133* ..
134* .. Executable Statements ..
135*
136 rmax = slamch( 'O' )
137 DO 20 j = 1, n
138 DO 10 i = 1, m
139 IF( ( a( i, j ).LT.-rmax ) .OR. ( a( i, j ).GT.rmax ) ) THEN
140 info = 1
141 GO TO 30
142 END IF
143 sa( i, j ) = real( a( i, j ) )
144 10 CONTINUE
145 20 CONTINUE
146 info = 0
147 30 CONTINUE
148 RETURN
149*
150* End of DLAG2S
151*
slamch
real function slamch(cmach)
SLAMCH
Definition slamch.f:68
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