dbsgq8.f
SUBROUTINE DBSGQ8 (FUN, XT, BC, N, KK, ID, A, B, INBV, ERR, ANS,
+ IERR, WORK)
C***BEGIN PROLOGUE DBSGQ8
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to DBFQAD
C***LIBRARY SLATEC
C***TYPE DOUBLE PRECISION (BSGQ8-S, DBSGQ8-D)
C***AUTHOR Jones, R. E., (SNLA)
C***DESCRIPTION
C
C Abstract **** A DOUBLE PRECISION routine ****
C
C DBSGQ8, a modification of GAUS8, integrates the
C product of FUN(X) by the ID-th derivative of a spline
C DBVALU(XT,BC,N,KK,ID,X,INBV,WORK) between limits A and B.
C
C Description of Arguments
C
C INPUT-- FUN,XT,BC,A,B,ERR are DOUBLE PRECISION
C FUN - Name of external function of one argument which
C multiplies DBVALU.
C XT - Knot array for DBVALU
C BC - B-coefficient array for DBVALU
C N - Number of B-coefficients for DBVALU
C KK - Order of the spline, KK.GE.1
C ID - Order of the spline derivative, 0.LE.ID.LE.KK-1
C A - Lower limit of integral
C B - Upper limit of integral (may be less than A)
C INBV- Initialization parameter for DBVALU
C ERR - Is a requested pseudorelative error tolerance. Normally
C pick a value of ABS(ERR).LT.1D-3. ANS will normally
C have no more error than ABS(ERR) times the integral of
C the absolute value of FUN(X)*DBVALU(XT,BC,N,KK,X,ID,
C INBV,WORK).
C
C
C OUTPUT-- ERR,ANS,WORK are DOUBLE PRECISION
C ERR - Will be an estimate of the absolute error in ANS if the
C input value of ERR was negative. (ERR is unchanged if
C the input value of ERR was nonnegative.) The estimated
C error is solely for information to the user and should
C not be used as a correction to the computed integral.
C ANS - Computed value of integral
C IERR- A status code
C --Normal Codes
C 1 ANS most likely meets requested error tolerance,
C or A=B.
C -1 A and B are too nearly equal to allow normal
C integration. ANS is set to zero.
C --Abnormal Code
C 2 ANS probably does not meet requested error tolerance.
C WORK- Work vector of length 3*K for DBVALU
C
C***SEE ALSO DBFQAD
C***ROUTINES CALLED D1MACH, DBVALU, I1MACH, XERMSG
C***REVISION HISTORY (YYMMDD)
C 800901 DATE WRITTEN
C 890531 Changed all specific intrinsics to generic. (WRB)
C 890911 Removed unnecessary intrinsics. (WRB)
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
C 900326 Removed duplicate information from DESCRIPTION section.
C (WRB)
C 900328 Added TYPE section. (WRB)
C 910408 Updated the AUTHOR section. (WRB)
C***END PROLOGUE DBSGQ8