1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
c
c-----------------------------------------------------------------------
c subroutine: r4tx
c radix 4 iteration subroutine
c-----------------------------------------------------------------------
c
subroutine r4tx(nthpo, cr0, cr1, cr2, cr3, ci0, ci1, ci2, ci3)
dimension cr0(2), cr1(2), cr2(2), cr3(2), ci0(2), ci1(2), ci2(2),
* ci3(2)
do 10 k=1,nthpo,4
r1 = cr0(k) + cr2(k)
r2 = cr0(k) - cr2(k)
r3 = cr1(k) + cr3(k)
r4 = cr1(k) - cr3(k)
fi1 = ci0(k) + ci2(k)
fi2 = ci0(k) - ci2(k)
fi3 = ci1(k) + ci3(k)
fi4 = ci1(k) - ci3(k)
cr0(k) = r1 + r3
ci0(k) = fi1 + fi3
cr1(k) = r1 - r3
ci1(k) = fi1 - fi3
cr2(k) = r2 - fi4
ci2(k) = fi2 + r4
cr3(k) = r2 + fi4
ci3(k) = fi2 - r4
10 continue
return
end
|
