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dlamchf77.f(3)				      LAPACK				   dlamchf77.f(3)

NAME
       dlamchf77.f -

SYNOPSIS
   Functions/Subroutines
       DOUBLE PRECISION function dlamch (CMACH)
	   DLAMCHF77 deprecated
       subroutine dlamc1 (BETA, T, RND, IEEE1)
	   DLAMC1
       subroutine dlamc2 (BETA, T, RND, EPS, EMIN, RMIN, EMAX, RMAX)
	   DLAMC2
       DOUBLE PRECISION function dlamc3 (A, B)
	   DLAMC3
       subroutine dlamc4 (EMIN, START, BASE)
	   DLAMC4
       subroutine dlamc5 (BETA, P, EMIN, IEEE, EMAX, RMAX)
	   DLAMC5

Function/Subroutine Documentation
   subroutine dlamc1 (integerBETA, integerT, logicalRND, logicalIEEE1)
       DLAMC1 Purpose:

	DLAMC1 determines the machine parameters given by BETA, T, RND, and
	IEEE1.

       Parameters:
	   BETA

		     The base of the machine.

	   T

		     The number of ( BETA ) digits in the mantissa.

	   RND

		     Specifies whether proper rounding	( RND = .TRUE. )  or
		     chopping  ( RND = .FALSE. )  occurs in addition. This may not
		     be a reliable guide to the way in which the machine performs
		     its arithmetic.

	   IEEE1

		     Specifies whether rounding appears to be done in the IEEE
		     'round to nearest' style.

       Author:
	   LAPACK is a software package provided by Univ. of Tennessee, Univ. of California
	   Berkeley, Univ. of Colorado Denver and NAG Ltd..

       Date:
	   April 2012

       Further Details

	 The routine is based on the routine  ENVRON  by Malcolm and
	 incorporates suggestions by Gentleman and Marovich. See

	    Malcolm M. A. (1972) Algorithms to reveal properties of
	       floating-point arithmetic. Comms. of the ACM, 15, 949-951.

	    Gentleman W. M. and Marovich S. B. (1974) More on algorithms
	       that reveal properties of floating point arithmetic units.
	       Comms. of the ACM, 17, 276-277.

       Definition at line 206 of file dlamchf77.f.

   subroutine dlamc2 (integerBETA, integerT, logicalRND, double precisionEPS, integerEMIN, double
       precisionRMIN, integerEMAX, double precisionRMAX)
       DLAMC2 Purpose:

	DLAMC2 determines the machine parameters specified in its argument
	list.

       Author:
	   LAPACK is a software package provided by Univ. of Tennessee, Univ. of California
	   Berkeley, Univ. of Colorado Denver and NAG Ltd..

       Date:
	   April 2012

       Parameters:
	   BETA

		     The base of the machine.

	   T

		     The number of ( BETA ) digits in the mantissa.

	   RND

		     Specifies whether proper rounding	( RND = .TRUE. )  or
		     chopping  ( RND = .FALSE. )  occurs in addition. This may not
		     be a reliable guide to the way in which the machine performs
		     its arithmetic.

	   EPS

		     The smallest positive number such that
			fl( 1.0 - EPS ) .LT. 1.0,
		     where fl denotes the computed value.

	   EMIN

		     The minimum exponent before (gradual) underflow occurs.

	   RMIN

		     The smallest normalized number for the machine, given by
		     BASE**( EMIN - 1 ), where	BASE  is the floating point value
		     of BETA.

	   EMAX

		     The maximum exponent before overflow occurs.

	   RMAX

		     The largest positive number for the machine, given by
		     BASE**EMAX * ( 1 - EPS ), where  BASE  is the floating point
		     value of BETA.

       Further Details

	 The computation of  EPS  is based on a routine PARANOIA by
	 W. Kahan of the University of California at Berkeley.

       Definition at line 419 of file dlamchf77.f.

   DOUBLE PRECISION function dlamc3 (double precisionA, double precisionB)
       DLAMC3 Purpose:

	DLAMC3	is intended to force  A  and  B  to be stored prior to doing
	the addition of  A  and  B ,  for use in situations where optimizers
	might hold one of these in a register.

       Parameters:
	   A
	   B

		     The values A and B.

       Definition at line 642 of file dlamchf77.f.

   subroutine dlamc4 (integerEMIN, double precisionSTART, integerBASE)
       DLAMC4 Purpose:

	DLAMC4 is a service routine for DLAMC2.

       Parameters:
	   EMIN

		     The minimum exponent before (gradual) underflow, computed by
		     setting A = START and dividing by BASE until the previous A
		     can not be recovered.

	   START

		     The starting point for determining EMIN.

	   BASE

		     The base of the machine.

       Definition at line 689 of file dlamchf77.f.

   subroutine dlamc5 (integerBETA, integerP, integerEMIN, logicalIEEE, integerEMAX, double
       precisionRMAX)
       DLAMC5 Purpose:

	DLAMC5 attempts to compute RMAX, the largest machine floating-point
	number, without overflow.  It assumes that EMAX + abs(EMIN) sum
	approximately to a power of 2.	It will fail on machines where this
	assumption does not hold, for example, the Cyber 205 (EMIN = -28625,
	EMAX = 28718).	It will also fail if the value supplied for EMIN is
	too large (i.e. too close to zero), probably with overflow.

       Parameters:
	   BETA

		     The base of floating-point arithmetic.

	   P

		     The number of base BETA digits in the mantissa of a
		     floating-point value.

	   EMIN

		     The minimum exponent before (gradual) underflow.

	   IEEE

		     A logical flag specifying whether or not the arithmetic
		     system is thought to comply with the IEEE standard.

	   EMAX

		     The largest exponent before overflow

	   RMAX

		     The largest machine floating-point number.

       Definition at line 796 of file dlamchf77.f.

   DOUBLE PRECISION function dlamch (characterCMACH)
       DLAMCHF77 deprecated Purpose:

	    DLAMCHF77 determines double precision machine parameters.

       Parameters:
	   CMACH

		     Specifies the value to be returned by DLAMCH:
		     = 'E' or 'e',   DLAMCH := eps
		     = 'S' or 's ,   DLAMCH := sfmin
		     = 'B' or 'b',   DLAMCH := base
		     = 'P' or 'p',   DLAMCH := eps*base
		     = 'N' or 'n',   DLAMCH := t
		     = 'R' or 'r',   DLAMCH := rnd
		     = 'M' or 'm',   DLAMCH := emin
		     = 'U' or 'u',   DLAMCH := rmin
		     = 'L' or 'l',   DLAMCH := emax
		     = 'O' or 'o',   DLAMCH := rmax
		     where
		     eps   = relative machine precision
		     sfmin = safe minimum, such that 1/sfmin does not overflow
		     base  = base of the machine
		     prec  = eps*base
		     t	   = number of (base) digits in the mantissa
		     rnd   = 1.0 when rounding occurs in addition, 0.0 otherwise
		     emin  = minimum exponent before (gradual) underflow
		     rmin  = underflow threshold - base**(emin-1)
		     emax  = largest exponent before overflow
		     rmax  = overflow threshold  - (base**emax)*(1-eps)

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   April 2012

       Definition at line 64 of file dlamchf77.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			   dlamchf77.f(3)
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