defer.f
SUBROUTINE DEFER (COFX, COFY, IDMN, USOL, GRHS)
C***BEGIN PROLOGUE DEFER
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to SEPELI
C***LIBRARY SLATEC
C***TYPE SINGLE PRECISION (DEFER-S)
C***AUTHOR (UNKNOWN)
C***DESCRIPTION
C
C This subroutine first approximates the truncation error given by
C TRUN1(X,Y)=DLX**2*TX+DLY**2*TY where
C TX=AFUN(X)*UXXXX/12.0+BFUN(X)*UXXX/6.0 on the interior and
C at the boundaries if periodic (here UXXX,UXXXX are the third
C and fourth partial derivatives of U with respect to X).
C TX is of the form AFUN(X)/3.0*(UXXXX/4.0+UXXX/DLX)
C at X=A or X=B if the boundary condition there is mixed.
C TX=0.0 along specified boundaries. TY has symmetric form
C in Y with X,AFUN(X),BFUN(X) replaced by Y,DFUN(Y),EFUN(Y).
C The second order solution in USOL is used to approximate
C (via second order finite differencing) the truncation error
C and the result is added to the right hand side in GRHS
C and then transferred to USOL to be used as a new right
C hand side when calling BLKTRI for a fourth order solution.
C
C***SEE ALSO SEPELI
C***ROUTINES CALLED DX, DY
C***COMMON BLOCKS SPLPCM
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 900402 Added TYPE section. (WRB)
C***END PROLOGUE DEFER