SCALAPACK 2.2.2
LAPACK: Linear Algebra PACKage
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◆ pcserrscal()

subroutine pcserrscal ( real  errbnd,
real  pusclr,
complex  x,
real  prec 
)

Definition at line 3709 of file pcblas1tst.f.

3710*
3711* -- PBLAS test routine (version 2.0) --
3712* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
3713* and University of California, Berkeley.
3714* April 1, 1998
3715*
3716* .. Scalar Arguments ..
3717 REAL ERRBND, PREC, PUSCLR
3718 COMPLEX X
3719* ..
3720*
3721* Purpose
3722* =======
3723*
3724* PCSERRSCAL serially computes the product PUSCLR * X and returns a
3725* scaled relative acceptable error bound on the result.
3726*
3727* Notes
3728* =====
3729*
3730* If s1 = PUSCLR*X and s2 are two different computed results, and s1 is
3731* being assumed to be correct, we require
3732*
3733* abs( s1 - s2 ) <= ERRBND = ERRFACT * abs( s1 ),
3734*
3735* where ERRFACT is computed as two times the machine precision.
3736*
3737* Arguments
3738* =========
3739*
3740* ERRBND (global output) REAL
3741* On exit, ERRBND specifies the scaled relative acceptable er-
3742* ror bound.
3743*
3744* PUSCLR (global input) REAL
3745* On entry, PUSCLR specifies the real scale factor.
3746*
3747* X (global input/global output) COMPLEX
3748* On entry, X specifies the scalar to be scaled. On exit, X is
3749* the scaled entry.
3750*
3751* PREC (global input) REAL
3752* On entry, PREC specifies the machine precision.
3753*
3754* -- Written on April 1, 1998 by
3755* Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
3756*
3757* =====================================================================
3758*
3759* .. Parameters ..
3760 REAL TWO
3761 parameter( two = 2.0e+0 )
3762* ..
3763* .. Intrinsic Functions ..
3764 INTRINSIC abs, aimag, cmplx, real
3765* ..
3766* .. Executable Statements ..
3767*
3768 x = cmplx( pusclr * real( x ), pusclr * aimag( x ) )
3769*
3770 errbnd = ( two * prec ) * abs( x )
3771*
3772 RETURN
3773*
3774* End of PCSERRSCAL
3775*
float cmplx[2]
Definition pblas.h:136
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