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subroutine dqag0(f, a, b, epsabs, epsrel, result, abserr,work,
* lwork, iwork, liwork, ifail)
c
c based on quadpack routine
c
c dqag0 is a general purpose integrator which calculates
c an approximation to the integral of a function over a finite
c interval (a,b)
c
c dqag0 itself is essentially a dummy routine whose function is to
c partition the work arrays work and iwork for use by dqags.
c work is partitioned into 4 arrays each of size lwork/4.
c iwork is a single array in dqags.
c
c .. scalar arguments ..
double precision a, abserr, b, epsabs, epsrel, result
integer ifail, liwork, lwork
c .. array arguments ..
double precision work(lwork)
integer iwork(liwork)
c .. function arguments ..
double precision f
c ..
c .. local scalars ..
c
integer ibl, iel, ier, irl, limit
c .. function references ..
c .. subroutine references ..
c dqags
c ..
external f
c check that minimum workspace requirements are met
if (lwork.lt.4) go to 20
if (liwork.lt.lwork/8+2) go to 20
c limit = upper bound on number of subintervals
limit = lwork/4
c set up base addresses for work arrays
ibl = limit + 1
iel = limit + ibl
irl = limit + iel
c perform integration
call dqags(f, a, b, abs(epsabs), abs(epsrel), work(1),work(ibl)
*, work(iel), work(irl), limit, iwork, liwork,result, abserr, ier)
if (ier.ne.0) go to 40
ifail = 0
go to 60
c error 6 = insufficient workspace
20 ier = 6
40 ifail = 1
60 return
end
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