d6/d27/zlag2c_8f_source.html

00001       SUBROUTINE ZLAG2C( M, N, A, LDA, SA, LDSA, INFO )
00002 *
00003 *  -- LAPACK PROTOTYPE auxiliary routine (version 3.1.2) --
00004 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
00005 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
00006 *     August 2007
00007 *
00008 *     ..
00009 *     .. Scalar Arguments ..
00010       INTEGER            INFO, LDA, LDSA, M, N
00011 *     ..
00012 *     .. Array Arguments ..
00013       COMPLEX            SA( LDSA, * )
00014       COMPLEX*16         A( LDA, * )
00015 *     ..
00016 *
00017 *  Purpose
00018 *  =======
00019 *
00020 *  ZLAG2C converts a COMPLEX*16 matrix, SA, to a COMPLEX matrix, A.
00021 *
00022 *  RMAX is the overflow for the SINGLE PRECISION arithmetic
00023 *  ZLAG2C checks that all the entries of A are between -RMAX and
00024 *  RMAX. If not the convertion is aborted and a flag is raised.
00025 *
00026 *  This is an auxiliary routine so there is no argument checking.
00027 *
00028 *  Arguments
00029 *  =========
00030 *
00031 *  M       (input) INTEGER
00032 *          The number of lines of the matrix A.  M >= 0.
00033 *
00034 *  N       (input) INTEGER
00035 *          The number of columns of the matrix A.  N >= 0.
00036 *
00037 *  A       (input) COMPLEX*16 array, dimension (LDA,N)
00038 *          On entry, the M-by-N coefficient matrix A.
00039 *
00040 *  LDA     (input) INTEGER
00041 *          The leading dimension of the array A.  LDA >= max(1,M).
00042 *
00043 *  SA      (output) COMPLEX array, dimension (LDSA,N)
00044 *          On exit, if INFO=0, the M-by-N coefficient matrix SA; if
00045 *          INFO>0, the content of SA is unspecified.
00046 *
00047 *  LDSA    (input) INTEGER
00048 *          The leading dimension of the array SA.  LDSA >= max(1,M).
00049 *
00050 *  INFO    (output) INTEGER
00051 *          = 0:  successful exit.
00052 *          = 1:  an entry of the matrix A is greater than the SINGLE
00053 *                PRECISION overflow threshold, in this case, the content
00054 *                of SA in exit is unspecified.
00055 *
00056 *  =========
00057 *
00058 *     .. Local Scalars ..
00059       INTEGER            I, J
00060       DOUBLE PRECISION   RMAX
00061 *     ..
00062 *     .. Intrinsic Functions ..
00063       INTRINSIC          DBLE, DIMAG
00064 *     ..
00065 *     .. External Functions ..
00066       REAL               SLAMCH
00067       EXTERNAL           SLAMCH
00068 *     ..
00069 *     .. Executable Statements ..
00070 *
00071       RMAX = SLAMCH( 'O' )
00072       DO 20 J = 1, N
00073          DO 10 I = 1, M
00074             IF( ( DBLE( A( I, J ) ).LT.-RMAX ) .OR.
00075      +          ( DBLE( A( I, J ) ).GT.RMAX ) .OR.
00076      +          ( DIMAG( A( I, J ) ).LT.-RMAX ) .OR.
00077      +          ( DIMAG( A( I, J ) ).GT.RMAX ) ) THEN
00078                INFO = 1
00079                GO TO 30
00080             END IF
00081             SA( I, J ) = A( I, J )
00082    10    CONTINUE
00083    20 CONTINUE
00084       INFO = 0
00085    30 CONTINUE
00086       RETURN
00087 *
00088 *     End of ZLAG2C
00089 *
00090       END