LAPACK  3.9.1
LAPACK: Linear Algebra PACKage

◆ zlag2c()

subroutine zlag2c ( integer  M,
integer  N,
complex*16, dimension( lda, * )  A,
integer  LDA,
complex, dimension( ldsa, * )  SA,
integer  LDSA,
integer  INFO 
)

ZLAG2C converts a complex double precision matrix to a complex single precision matrix.

Download ZLAG2C + dependencies [TGZ] [ZIP] [TXT]

Purpose:
 ZLAG2C converts a COMPLEX*16 matrix, SA, to a COMPLEX matrix, A.

 RMAX is the overflow for the SINGLE PRECISION arithmetic
 ZLAG2C 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 COMPLEX*16 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 COMPLEX 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 106 of file zlag2c.f.

107 *
108 * -- LAPACK auxiliary routine --
109 * -- LAPACK is a software package provided by Univ. of Tennessee, --
110 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
111 *
112 * .. Scalar Arguments ..
113  INTEGER INFO, LDA, LDSA, M, N
114 * ..
115 * .. Array Arguments ..
116  COMPLEX SA( LDSA, * )
117  COMPLEX*16 A( LDA, * )
118 * ..
119 *
120 * =====================================================================
121 *
122 * .. Local Scalars ..
123  INTEGER I, J
124  DOUBLE PRECISION RMAX
125 * ..
126 * .. Intrinsic Functions ..
127  INTRINSIC dble, dimag
128 * ..
129 * .. External Functions ..
130  REAL SLAMCH
131  EXTERNAL slamch
132 * ..
133 * .. Executable Statements ..
134 *
135  rmax = slamch( 'O' )
136  DO 20 j = 1, n
137  DO 10 i = 1, m
138  IF( ( dble( a( i, j ) ).LT.-rmax ) .OR.
139  $ ( dble( a( i, j ) ).GT.rmax ) .OR.
140  $ ( dimag( a( i, j ) ).LT.-rmax ) .OR.
141  $ ( dimag( a( i, j ) ).GT.rmax ) ) THEN
142  info = 1
143  GO TO 30
144  END IF
145  sa( i, j ) = a( i, j )
146  10 CONTINUE
147  20 CONTINUE
148  info = 0
149  30 CONTINUE
150  RETURN
151 *
152 * End of ZLAG2C
153 *
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:68
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