LAPACK  3.8.0
LAPACK: Linear Algebra PACKage

◆ 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, SA, to a SINGLE
 PRECISION matrix, A.

 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.
Date
December 2016

Definition at line 110 of file dlag2s.f.

110 *
111 * -- LAPACK auxiliary routine (version 3.7.0) --
112 * -- LAPACK is a software package provided by Univ. of Tennessee, --
113 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
114 * December 2016
115 *
116 * .. Scalar Arguments ..
117  INTEGER info, lda, ldsa, m, n
118 * ..
119 * .. Array Arguments ..
120  REAL sa( ldsa, * )
121  DOUBLE PRECISION a( lda, * )
122 * ..
123 *
124 * =====================================================================
125 *
126 * .. Local Scalars ..
127  INTEGER i, j
128  DOUBLE PRECISION rmax
129 * ..
130 * .. External Functions ..
131  REAL slamch
132  EXTERNAL slamch
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 ) = a( i, j )
144  10 CONTINUE
145  20 CONTINUE
146  info = 0
147  30 CONTINUE
148  RETURN
149 *
150 * End of DLAG2S
151 *
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:69
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