1subroutine flat1a(psavg,nsmo,s2,nh,nsteps,nhmax,nsmax)
2
3  real psavg(nh)
4  real s2(nhmax,nsmax)
5  real x(8192)
6
7  ia=nsmo/2 + 1
8  ib=nh - nsmo/2 - 1
9  do i=ia,ib
10     call pctile(psavg(i-nsmo/2),nsmo,50,x(i))
11  enddo
12  do i=1,ia-1
13     x(i)=x(ia)
14  enddo
15  do i=ib+1,nh
16     x(i)=x(ib)
17  enddo
18
19  do i=1,nh
20     psavg(i)=psavg(i)/x(i)
21     do j=1,nsteps
22        s2(i,j)=s2(i,j)/x(i)
23     enddo
24  enddo
25
26  return
27end subroutine flat1a
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30