cdzro.f
SUBROUTINE CDZRO (AE, F, H, N, NQ, IROOT, RE, T, YH, UROUND, B, C,
8 FB, FC, Y)
C***BEGIN PROLOGUE CDZRO
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE CDZRO searches for a zero of a function F(N, T, Y, IROOT)
C between the given values B and C until the width of the
C interval (B, C) has collapsed to within a tolerance
C specified by the stopping criterion,
C ABS(B - C) .LE. 2.*(RW*ABS(B) + AE).
C***LIBRARY SLATEC (SDRIVE)
C***TYPE COMPLEX (SDZRO-S, DDZRO-D, CDZRO-C)
C***AUTHOR Kahaner, D. K., (NIST)
C National Institute of Standards and Technology
C Gaithersburg, MD 20899
C Sutherland, C. D., (LANL)
C Mail Stop D466
C Los Alamos National Laboratory
C Los Alamos, NM 87545
C***DESCRIPTION
C
C This is a special purpose version of ZEROIN, modified for use with
C the CDRIV package.
C
C Sandia Mathematical Program Library
C Mathematical Computing Services Division 5422
C Sandia Laboratories
C P. O. Box 5800
C Albuquerque, New Mexico 87115
C Control Data 6600 Version 4.5, 1 November 1971
C
C PARAMETERS
C F - Name of the external function, which returns a
C real result. This name must be in an
C EXTERNAL statement in the calling program.
C B - One end of the interval (B, C). The value returned for
C B usually is the better approximation to a zero of F.
C C - The other end of the interval (B, C).
C RE - Relative error used for RW in the stopping criterion.
C If the requested RE is less than machine precision,
C then RW is set to approximately machine precision.
C AE - Absolute error used in the stopping criterion. If the
C given interval (B, C) contains the origin, then a
C nonzero value should be chosen for AE.
C
C***REFERENCES L. F. Shampine and H. A. Watts, ZEROIN, a root-solving
C routine, SC-TM-70-631, Sept 1970.
C T. J. Dekker, Finding a zero by means of successive
C linear interpolation, Constructive Aspects of the
C Fundamental Theorem of Algebra, edited by B. Dejon
C and P. Henrici, 1969.
C***ROUTINES CALLED CDNTP
C***REVISION HISTORY (YYMMDD)
C 790601 DATE WRITTEN
C 900329 Initial submission to SLATEC.
C***END PROLOGUE CDZRO