LAPACK  3.10.0
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.

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 * .. Executable Statements ..
132 *
133  rmax = slamch( 'O' )
134  DO 20 j = 1, n
135  DO 10 i = 1, m
136  IF( ( a( i, j ).LT.-rmax ) .OR. ( a( i, j ).GT.rmax ) ) THEN
137  info = 1
138  GO TO 30
139  END IF
140  sa( i, j ) = a( i, j )
141  10 CONTINUE
142  20 CONTINUE
143  info = 0
144  30 CONTINUE
145  RETURN
146 *
147 * End of DLAG2S
148 *
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:68
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