28 lines
440 B
Fortran
28 lines
440 B
Fortran
|
subroutine ps4(dat,nfft,s)
|
||
|
|
|
||
|
|
parameter (NMAX=2520+2)
|
||
|
|
parameter (NHMAX=NMAX/2-1)
|
||
|
|
real dat(nfft)
|
||
|
|
real dat2(NMAX)
|
||
|
|
real s(NHMAX)
|
||
|
|
complex c(0:NMAX)
|
||
|
|
equivalence(dat2,c)
|
||
|
|
|
||
|
|
nh=nfft/2
|
||
|
|
do i=1,nh
|
||
|
|
dat2(i)=dat(i)/128.0 !### Why 128 ??
|
||
|
|
enddo
|
||
|
|
do i=nh+1,nfft
|
||
|
|
dat2(i)=0.
|
||
|
|
enddo
|
||
|
|
|
||
|
|
call four2a(c,nfft,1,-1,0)
|
||
|
|
|
||
|
|
fac=1.0/nfft
|
||
|
|
do i=1,nh
|
||
|
|
s(i)=fac*(real(c(i))**2 + aimag(c(i))**2)
|
||
|
|
enddo
|
||
|
|
|
||
|
|
return
|
||
|
|
end subroutine ps4
|