dsoseq.f
SUBROUTINE DSOSEQ (FNC, N, S, RTOLX, ATOLX, TOLF, IFLAG, MXIT,
+ NCJS, NSRRC, NSRI, IPRINT, FMAX, C, NC, B, P, TEMP, X, Y, FAC,
+ IS)
C***BEGIN PROLOGUE DSOSEQ
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to DSOS
C***LIBRARY SLATEC
C***TYPE DOUBLE PRECISION (SOSEQS-S, DSOSEQ-D)
C***AUTHOR (UNKNOWN)
C***DESCRIPTION
C
C DSOSEQ solves a system of N simultaneous nonlinear equations.
C See the comments in the interfacing routine DSOS for a more
C detailed description of some of the items in the calling list.
C
C **********************************************************************
C -Input-
C
C FNC- Function subprogram which evaluates the equations
C N -number of equations
C S -Solution vector of initial guesses
C RTOLX-Relative error tolerance on solution components
C ATOLX-Absolute error tolerance on solution components
C TOLF-Residual error tolerance
C MXIT-Maximum number of allowable iterations.
C NCJS-Maximum number of consecutive iterative steps to perform
C using the same triangular Jacobian matrix approximation.
C NSRRC-Number of consecutive iterative steps for which the
C limiting precision accuracy test must be satisfied
C before the routine exits with IFLAG=4.
C NSRI-Number of consecutive iterative steps for which the
C diverging condition test must be satisfied before
C the routine exits with IFLAG=7.
C IPRINT-Internal printing parameter. You must set IPRINT=-1 if you
C want the intermediate solution iterates and a residual norm
C to be printed.
C C -Internal work array, dimensioned at least N*(N+1)/2.
C NC -Dimension of C array. NC .GE. N*(N+1)/2.
C B -Internal work array, dimensioned N.
C P -Internal work array, dimensioned N.
C TEMP-Internal work array, dimensioned N.
C X -Internal work array, dimensioned N.
C Y -Internal work array, dimensioned N.
C FAC -Internal work array, dimensioned N.
C IS -Internal work array, dimensioned N.
C
C -Output-
C S -Solution vector
C IFLAG-Status indicator flag
C MXIT-The actual number of iterations performed
C FMAX-Residual norm
C C -Upper unit triangular matrix which approximates the
C forward triangularization of the full Jacobian matrix.
C Stored in a vector with dimension at least N*(N+1)/2.
C B -Contains the residuals (function values) divided
C by the corresponding components of the P vector
C P -Array used to store the partial derivatives. After
C each iteration P(K) contains the maximal derivative
C occurring in the K-th reduced equation.
C TEMP-Array used to store the previous solution iterate.
C X -Solution vector. Contains the values achieved on the
C last iteration loop upon exit from DSOS.
C Y -Array containing the solution increments.
C FAC -Array containing factors used in computing numerical
C derivatives.
C IS -Records the pivotal information (column interchanges)
C
C **********************************************************************
C *** Three machine dependent parameters appear in this subroutine.
C
C *** The smallest positive magnitude, zero, is defined by the function
C *** routine D1MACH(1).
C
C *** URO, the computer unit roundoff value, is defined by D1MACH(3) for
C *** machines that round or D1MACH(4) for machines that truncate.
C *** URO is the smallest positive number such that 1.+URO .GT. 1.
C
C *** The output tape unit number, LOUN, is defined by the function
C *** I1MACH(2).
C **********************************************************************
C
C***SEE ALSO DSOS
C***ROUTINES CALLED D1MACH, DSOSSL, I1MACH
C***REVISION HISTORY (YYMMDD)
C 801001 DATE WRITTEN
C 890531 Changed all specific intrinsics to generic. (WRB)
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900328 Added TYPE section. (WRB)
C***END PROLOGUE DSOSEQ