DEFER(3)

SYNOPSIS
SUBROUTINE DEFER (COFX, COFY, IDMN, USOL, GRHS)

NAME
defer - Subsidiary to SEPELI

LIBRARY
SLATEC

TYPE
SINGLE PRECISION (DEFER-S)

AUTHOR
(UNKNOWN)

DESCRIPTION
This subroutine first approximates the truncation error given by TRUN1(X,Y)=DLX**2*TX+DLY**2*TY where TX=AFUN(X)*UXXXX/12.0+BFUN(X)*UXXX/6.0 on the interior and at the boundaries if periodic (here UXXX,UXXXX are the third and fourth partial derivatives of U with respect to X). TX is of the form AFUN(X)/3.0*(UXXXX/4.0+UXXX/DLX) at X=A or X=B if the boundary condition there is mixed. TX=0.0 along specified boundaries. TY has symmetric form in Y with X,AFUN(X),BFUN(X) replaced by Y,DFUN(Y),EFUN(Y). The second order solution in USOL is used to approximate (via second order finite differencing) the truncation error and the result is added to the right hand side in GRHS and then transferred to USOL to be used as a new right hand side when calling BLKTRI for a fourth order solution.

SEE ALSO
SEPELI

ROUTINES CALLED
DX, DY

COMMON BLOCKS
SPLPCM

REVISION HISTORY (YYMMDD)
801001 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
891214 Prologue converted to Version 4.0 format. (BAB)
900402 Added TYPE section. (WRB)