fftstp.f90

基于linux操作下的fortran快速付立变换的程序

        nout1=nout1+atn
        nout2=nout1+after
        nout3=nout2+after
        do 3090,j=1,n1dfft
        r1=zin(1,j,nin1)
        s1=zin(2,j,nin1)
        r=zin(1,j,nin2)
        s=zin(2,j,nin2)
        r2=r*cr2 - s*ci2
        s2=r*ci2 + s*cr2
        r=zin(1,j,nin3)
        s=zin(2,j,nin3)
        r3=r*cr3 - s*ci3
        s3=r*ci3 + s*cr3
        r=r2 + r3
        s=s2 + s3
        zout(1,j,nout1) = r + r1
        zout(2,j,nout1) = s + s1
        r1=r1 - .5d0*r
        s1=s1 - .5d0*s
        r2=bb*(r2-r3)
        s2=bb*(s2-s3)
        zout(1,j,nout2) = r1 - s2 
        zout(2,j,nout2) = s1 + r2
        zout(1,j,nout3) = r1 + s2 
        zout(2,j,nout3) = s1 - r2
3090        continue
        endif
3000        continue
        else if (now.eq.5) then
!         cos(2.d0*pi/5.d0)
        cos2=0.3090169943749474d0
!         cos(4.d0*pi/5.d0)
        cos4=-0.8090169943749474d0
!        sin(2.d0*pi/5.d0)
        sin2=isign*0.9510565162951536d0
!         sin(4.d0*pi/5.d0)
        sin4=isign*0.5877852522924731d0
        ia=1
        nin1=ia-after
        nout1=ia-atn
        do 5001,ib=1,before
        nin1=nin1+after
        nin2=nin1+atb
        nin3=nin2+atb
        nin4=nin3+atb
        nin5=nin4+atb
        nout1=nout1+atn
        nout2=nout1+after
        nout3=nout2+after
        nout4=nout3+after
        nout5=nout4+after
        do 5001,j=1,n1dfft
        r1=zin(1,j,nin1)
        s1=zin(2,j,nin1)
        r2=zin(1,j,nin2)
        s2=zin(2,j,nin2)
        r3=zin(1,j,nin3)
        s3=zin(2,j,nin3)
        r4=zin(1,j,nin4)
        s4=zin(2,j,nin4)
        r5=zin(1,j,nin5)
        s5=zin(2,j,nin5)
        r25 = r2 + r5
        r34 = r3 + r4
        s25 = s2 - s5
        s34 = s3 - s4
        zout(1,j,nout1) = r1 + r25 + r34
        r = r1 + cos2*r25 + cos4*r34
        s = sin2*s25 + sin4*s34
        zout(1,j,nout2) = r - s
        zout(1,j,nout5) = r + s
        r = r1 + cos4*r25 + cos2*r34
        s = sin4*s25 - sin2*s34
        zout(1,j,nout3) = r - s
        zout(1,j,nout4) = r + s
        r25 = r2 - r5
        r34 = r3 - r4
        s25 = s2 + s5
        s34 = s3 + s4
        zout(2,j,nout1) = s1 + s25 + s34
        r = s1 + cos2*s25 + cos4*s34
        s = sin2*r25 + sin4*r34
        zout(2,j,nout2) = r + s
        zout(2,j,nout5) = r - s
        r = s1 + cos4*s25 + cos2*s34
        s = sin4*r25 - sin2*r34
        zout(2,j,nout3) = r + s
        zout(2,j,nout4) = r - s
5001        continue
        do 5000,ia=2,after
        ias=ia-1
        if (8*ias.eq.5*after) then
                if (isign.eq.1) then
                        nin1=ia-after
                        nout1=ia-atn
                        do 5010,ib=1,before
                        nin1=nin1+after
                        nin2=nin1+atb
                        nin3=nin2+atb
                        nin4=nin3+atb
                        nin5=nin4+atb        
                        nout1=nout1+atn
                        nout2=nout1+after
                        nout3=nout2+after
                        nout4=nout3+after
                        nout5=nout4+after
                        do 5010,j=1,n1dfft
                        r1=zin(1,j,nin1)
                        s1=zin(2,j,nin1)
                        r=zin(1,j,nin2)
                        s=zin(2,j,nin2)
                        r2=(r - s)*rt2i
                        s2=(r + s)*rt2i
                        r3=zin(2,j,nin3)
                        s3=zin(1,j,nin3) 
                        r=zin(1,j,nin4)
                        s=zin(2,j,nin4)
                        r4=(r + s)*rt2i
                        s4=(r - s)*rt2i
                        r5=zin(1,j,nin5)
                        s5=zin(2,j,nin5)
                        r25 = r2 - r5
                        r34 = r3 + r4
                        s25 = s2 + s5
                        s34 = s3 - s4
                        zout(1,j,nout1) = r1 + r25 - r34
                        r = r1 + cos2*r25 - cos4*r34 
                        s = sin2*s25 + sin4*s34
                        zout(1,j,nout2) = r - s
                        zout(1,j,nout5) = r + s
                        r = r1 + cos4*r25 - cos2*r34 
                        s = sin4*s25 - sin2*s34
                        zout(1,j,nout3) = r - s
                        zout(1,j,nout4) = r + s
                        r25 = r2 + r5
                        r34 = r4 - r3
                        s25 = s2 - s5
                        s34 = s3 + s4
                        zout(2,j,nout1) = s1 + s25 + s34
                        r = s1 + cos2*s25 + cos4*s34
                        s = sin2*r25 + sin4*r34
                        zout(2,j,nout2) = r + s
                        zout(2,j,nout5) = r - s
                        r = s1 + cos4*s25 + cos2*s34
                        s = sin4*r25 - sin2*r34
                        zout(2,j,nout3) = r + s
                        zout(2,j,nout4) = r - s
5010                        continue
                else
                        nin1=ia-after
                        nout1=ia-atn
                        do 5020,ib=1,before
                        nin1=nin1+after
                        nin2=nin1+atb
                        nin3=nin2+atb
                        nin4=nin3+atb
                        nin5=nin4+atb        
                        nout1=nout1+atn
                        nout2=nout1+after
                        nout3=nout2+after
                        nout4=nout3+after
                        nout5=nout4+after
                        do 5020,j=1,n1dfft
                        r1=zin(1,j,nin1)
                        s1=zin(2,j,nin1)
                        r=zin(1,j,nin2)
                        s=zin(2,j,nin2)
                        r2=(r + s)*rt2i
                        s2=(s - r)*rt2i
                        r3=zin(2,j,nin3)
                        s3=zin(1,j,nin3)
                        r=zin(1,j,nin4)
                        s=zin(2,j,nin4)
                        r4=(s - r)*rt2i
                        s4=(r + s)*rt2i
                        r5=zin(1,j,nin5)
                        s5=zin(2,j,nin5)
                        r25 = r2 - r5
                        r34 = r3 + r4
                        s25 = s2 + s5
                        s34 = s4 - s3
                        zout(1,j,nout1) = r1 + r25 + r34
                        r = r1 + cos2*r25 + cos4*r34
                        s = sin2*s25 + sin4*s34
                        zout(1,j,nout2) = r - s
                        zout(1,j,nout5) = r + s
                        r = r1 + cos4*r25 + cos2*r34
                        s = sin4*s25 - sin2*s34
                        zout(1,j,nout3) = r - s
                        zout(1,j,nout4) = r + s
                        r25 = r2 + r5
                        r34 = r3 - r4
                        s25 = s2 - s5
                        s34 = s3 + s4
                        zout(2,j,nout1) = s1 + s25 - s34
                        r = s1 + cos2*s25 - cos4*s34
                        s = sin2*r25 + sin4*r34
                        zout(2,j,nout2) = r + s
                        zout(2,j,nout5) = r - s
                        r = s1 + cos4*s25 - cos2*s34
                        s = sin4*r25 - sin2*r34
                        zout(2,j,nout3) = r + s
                        zout(2,j,nout4) = r - s
5020                        continue
                endif
        else
                ias=ia-1
                itt=ias*before
                itrig=itt+1
                cr2=trig(1,itrig)
                ci2=trig(2,itrig)
                itrig=itrig+itt
                cr3=trig(1,itrig)
                ci3=trig(2,itrig)
                itrig=itrig+itt
                cr4=trig(1,itrig)
                ci4=trig(2,itrig)
                itrig=itrig+itt
                cr5=trig(1,itrig)
                ci5=trig(2,itrig)
                nin1=ia-after
                nout1=ia-atn
                do 5100,ib=1,before
                nin1=nin1+after
                nin2=nin1+atb
                nin3=nin2+atb
                nin4=nin3+atb
                nin5=nin4+atb
                nout1=nout1+atn
                nout2=nout1+after
                nout3=nout2+after
                nout4=nout3+after
                nout5=nout4+after
                do 5100,j=1,n1dfft
                r1=zin(1,j,nin1)
                s1=zin(2,j,nin1)
                r=zin(1,j,nin2)
                s=zin(2,j,nin2)
                r2=r*cr2 - s*ci2
                s2=r*ci2 + s*cr2
                r=zin(1,j,nin3)
                s=zin(2,j,nin3)
                r3=r*cr3 - s*ci3
                s3=r*ci3 + s*cr3
                r=zin(1,j,nin4)
                s=zin(2,j,nin4)
                r4=r*cr4 - s*ci4
                s4=r*ci4 + s*cr4
                r=zin(1,j,nin5)
                s=zin(2,j,nin5)
                r5=r*cr5 - s*ci5
                s5=r*ci5 + s*cr5
                r25 = r2 + r5
                r34 = r3 + r4
                s25 = s2 - s5
                s34 = s3 - s4
                zout(1,j,nout1) = r1 + r25 + r34
                r = r1 + cos2*r25 + cos4*r34
                s = sin2*s25 + sin4*s34
                zout(1,j,nout2) = r - s
                zout(1,j,nout5) = r + s
                r = r1 + cos4*r25 + cos2*r34
                s = sin4*s25 - sin2*s34
                zout(1,j,nout3) = r - s
                zout(1,j,nout4) = r + s
                r25 = r2 - r5
                r34 = r3 - r4
                s25 = s2 + s5
                s34 = s3 + s4
                zout(2,j,nout1) = s1 + s25 + s34
                r = s1 + cos2*s25 + cos4*s34
                s = sin2*r25 + sin4*r34
                zout(2,j,nout2) = r + s
                zout(2,j,nout5) = r - s
                r = s1 + cos4*s25 + cos2*s34
                s = sin4*r25 - sin2*r34
                zout(2,j,nout3) = r + s
                zout(2,j,nout4) = r - s
5100                continue
        endif
5000        continue
       else if (now.eq.6) then
!         .5d0*sqrt(3.d0)
        bb=isign*0.8660254037844387d0

        ia=1
        nin1=ia-after
        nout1=ia-atn
        do 6120,ib=1,before
        nin1=nin1+after
        nin2=nin1+atb
        nin3=nin2+atb
        nin4=nin3+atb
        nin5=nin4+atb
        nin6=nin5+atb
        nout1=nout1+atn
        nout2=nout1+after
        nout3=nout2+after
        nout4=nout3+after
        nout5=nout4+after
        nout6=nout5+after
        do 6120,j=1,n1dfft
        r2=zin(1,j,nin3)
        s2=zin(2,j,nin3)
        r3=zin(1,j,nin5)
        s3=zin(2,j,nin5)
        r=r2 + r3
        s=s2 + s3
        r1=zin(1,j,nin1)
        s1=zin(2,j,nin1)
        ur1 = r + r1
        ui1 = s + s1
        r1=r1 - .5d0*r
        s1=s1 - .5d0*s
        r=r2-r3
        s=s2-s3
        ur2 = r1 - s*bb
        ui2 = s1 + r*bb
        ur3 = r1 + s*bb
        ui3 = s1 - r*bb

        r2=zin(1,j,nin6)
        s2=zin(2,j,nin6)
        r3=zin(1,j,nin2)
        s3=zin(2,j,nin2)
        r=r2 + r3
        s=s2 + s3
        r1=zin(1,j,nin4)
        s1=zin(2,j,nin4)
        vr1 = r + r1
        vi1 = s + s1
        r1=r1 - .5d0*r
        s1=s1 - .5d0*s
        r=r2-r3
        s=s2-s3
        vr2 = r1 - s*bb
        vi2 = s1 + r*bb
        vr3 = r1 + s*bb
        vi3 = s1 - r*bb

        zout(1,j,nout1)=ur1+vr1
        zout(2,j,nout1)=ui1+vi1
        zout(1,j,nout5)=ur2+vr2
        zout(2,j,nout5)=ui2+vi2
        zout(1,j,nout3)=ur3+vr3
        zout(2,j,nout3)=ui3+vi3
        zout(1,j,nout4)=ur1-vr1
        zout(2,j,nout4)=ui1-vi1
        zout(1,j,nout2)=ur2-vr2
        zout(2,j,nout2)=ui2-vi2
        zout(1,j,nout6)=ur3-vr3
        zout(2,j,nout6)=ui3-vi3
6120        continue

        else 
        stop 'error fftstp'
        endif

        return
        end