DSOSEQ(3)

SYNOPSIS
SUBROUTINE DSOSEQ (FNC, N, S, RTOLX, ATOLX, TOLF, IFLAG, MXIT, + NCJS, NSRRC, NSRI, IPRINT, FMAX, C, NC, B, P, TEMP, X, Y, FAC, + IS)

NAME
dsoseq - Subsidiary to DSOS

LIBRARY
SLATEC

TYPE
DOUBLE PRECISION (SOSEQS-S, DSOSEQ-D)

AUTHOR
(UNKNOWN)

DESCRIPTION
DSOSEQ solves a system of N simultaneous nonlinear equations. See the comments in the interfacing routine DSOS for a more detailed description of some of the items in the calling list. ********************************************************************** -Input- FNC- Function subprogram which evaluates the equations N -number of equations S -Solution vector of initial guesses RTOLX-Relative error tolerance on solution components ATOLX-Absolute error tolerance on solution components TOLF-Residual error tolerance MXIT-Maximum number of allowable iterations. NCJS-Maximum number of consecutive iterative steps to perform using the same triangular Jacobian matrix approximation. NSRRC-Number of consecutive iterative steps for which the limiting precision accuracy test must be satisfied before the routine exits with IFLAG=4. NSRI-Number of consecutive iterative steps for which the diverging condition test must be satisfied before the routine exits with IFLAG=7. IPRINT-Internal printing parameter. You must set IPRINT=-1 if you want the intermediate solution iterates and a residual norm to be printed. C -Internal work array, dimensioned at least N*(N+1)/2. NC -Dimension of C array. NC .GE. N*(N+1)/2. B -Internal work array, dimensioned N. P -Internal work array, dimensioned N. TEMP-Internal work array, dimensioned N. X -Internal work array, dimensioned N. Y -Internal work array, dimensioned N. FAC -Internal work array, dimensioned N. IS -Internal work array, dimensioned N. -Output- S -Solution vector IFLAG-Status indicator flag MXIT-The actual number of iterations performed FMAX-Residual norm C -Upper unit triangular matrix which approximates the forward triangularization of the full Jacobian matrix. Stored in a vector with dimension at least N*(N+1)/2. B -Contains the residuals (function values) divided by the corresponding components of the P vector P -Array used to store the partial derivatives. After each iteration P(K) contains the maximal derivative occurring in the K-th reduced equation. TEMP-Array used to store the previous solution iterate. X -Solution vector. Contains the values achieved on the last iteration loop upon exit from DSOS. Y -Array containing the solution increments. FAC -Array containing factors used in computing numerical derivatives. IS -Records the pivotal information (column interchanges) ********************************************************************** *** Three machine dependent parameters appear in this subroutine. *** The smallest positive magnitude, zero, is defined by the function *** routine D1MACH(1). *** URO, the computer unit roundoff value, is defined by D1MACH(3) for *** machines that round or D1MACH(4) for machines that truncate. *** URO is the smallest positive number such that 1.+URO .GT. 1. *** The output tape unit number, LOUN, is defined by the function *** I1MACH(2). **********************************************************************

SEE ALSO
DSOS

ROUTINES CALLED
D1MACH, DSOSSL, I1MACH

REVISION HISTORY (YYMMDD)
801001 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
891214 Prologue converted to Version 4.0 format. (BAB)
900328 Added TYPE section. (WRB)