fftstp.f90

基于linux操作下的fortran快速付立变换的程序

                        s8=zin(2,j,nin8)
                        r=r1 + r5
                        s=r3 + r7
                        ap=r + s
                        am=r - s
                        r=r2 + r6
                        s=r4 + r8
                        bp=r + s
                        bm=r - s
                        r=s1 + s5
                        s=s3 + s7
                        cp=r + s
                        cm=r - s
                        r=s2 + s6
                        s=s4 + s8
                        dp=r + s
                        dm=r - s
                        zout(1,j,nout1) = ap + bp
                        zout(2,j,nout1) = cp + dp
                        zout(1,j,nout5) = ap - bp
                        zout(2,j,nout5) = cp - dp
                        zout(1,j,nout3) = am - dm
                        zout(2,j,nout3) = cm + bm
                        zout(1,j,nout7) = am + dm
                        zout(2,j,nout7) = cm - bm
                        r= r1 - r5
                        s=-s3 + s7
                        ap=r + s
                        am=r - s
                        r=s1 - s5
                        s=r7 - r3
                        bp=r + s
                        bm=r - s
                        r=-s4 + s8
                        s= r2 - r6
                        cp=r + s
                        cm=r - s
                        r=-s2 + s6
                        s= r4 - r8
                        dp=r + s
                        dm=r - s
                        r = ( cp + dm)*rt2i
                        s = ( cp - dm)*rt2i
                        cp= ( cm + dp)*rt2i
                        dp= ( dp - cm)*rt2i
                        zout(1,j,nout2) = ap + r
                        zout(2,j,nout2) = bm + s
                        zout(1,j,nout6) = ap - r
                        zout(2,j,nout6) = bm - s
                        zout(1,j,nout4) = am + cp
                        zout(2,j,nout4) = bp + dp
                        zout(1,j,nout8) = am - cp
                        zout(2,j,nout8) = bp - dp
8121                        continue

                do 8001,ia=2,after
                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)
                        itrig=itrig+itt
                        cr6=trig(1,itrig)
                        ci6=trig(2,itrig)
                        itrig=itrig+itt
                        cr7=trig(1,itrig)
                        ci7=trig(2,itrig)
                        itrig=itrig+itt
                        cr8=trig(1,itrig)
                        ci8=trig(2,itrig)
                        nin1=ia-after
                        nout1=ia-atn
                        do 8021,ib=1,before
                        nin1=nin1+after
                        nin2=nin1+atb
                        nin3=nin2+atb
                        nin4=nin3+atb
                        nin5=nin4+atb
                        nin6=nin5+atb
                        nin7=nin6+atb
                        nin8=nin7+atb
                        nout1=nout1+atn
                        nout2=nout1+after
                        nout3=nout2+after
                        nout4=nout3+after
                        nout5=nout4+after
                        nout6=nout5+after
                        nout7=nout6+after
                        nout8=nout7+after
                        do 8021,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
                        r=zin(1,j,nin6)
                        s=zin(2,j,nin6)
                        r6=r*cr6 - s*ci6
                        s6=r*ci6 + s*cr6
                        r=zin(1,j,nin7)
                        s=zin(2,j,nin7)
                        r7=r*cr7 - s*ci7
                        s7=r*ci7 + s*cr7
                        r=zin(1,j,nin8)
                        s=zin(2,j,nin8)
                        r8=r*cr8 - s*ci8
                        s8=r*ci8 + s*cr8
                        r=r1 + r5
                        s=r3 + r7
                        ap=r + s
                        am=r - s
                        r=r2 + r6
                        s=r4 + r8
                        bp=r + s
                        bm=r - s
                        r=s1 + s5
                        s=s3 + s7
                        cp=r + s
                        cm=r - s
                        r=s2 + s6
                        s=s4 + s8
                        dp=r + s
                        dm=r - s
                        zout(1,j,nout1) = ap + bp
                        zout(2,j,nout1) = cp + dp
                        zout(1,j,nout5) = ap - bp
                        zout(2,j,nout5) = cp - dp
                        zout(1,j,nout3) = am - dm
                        zout(2,j,nout3) = cm + bm
                        zout(1,j,nout7) = am + dm
                        zout(2,j,nout7) = cm - bm
                        r= r1 - r5
                        s=-s3 + s7
                        ap=r + s
                        am=r - s
                        r=s1 - s5
                        s=r7 - r3
                        bp=r + s
                        bm=r - s
                        r=-s4 + s8
                        s= r2 - r6
                        cp=r + s
                        cm=r - s
                        r=-s2 + s6
                        s= r4 - r8
                        dp=r + s
                        dm=r - s
                        r = ( cp + dm)*rt2i
                        s = ( cp - dm)*rt2i
                        cp= ( cm + dp)*rt2i
                        dp= ( dp - cm)*rt2i
                        zout(1,j,nout2) = ap + r
                        zout(2,j,nout2) = bm + s
                        zout(1,j,nout6) = ap - r
                        zout(2,j,nout6) = bm - s
                        zout(1,j,nout4) = am + cp
                        zout(2,j,nout4) = bp + dp
                        zout(1,j,nout8) = am - cp
                        zout(2,j,nout8) = bp - dp
8021                        continue
8001                continue

        endif
        else if (now.eq.3) then 
!         .5d0*sqrt(3.d0)
        bb=isign*0.8660254037844387d0
        ia=1
        nin1=ia-after
        nout1=ia-atn
        do 3001,ib=1,before
        nin1=nin1+after
        nin2=nin1+atb
        nin3=nin2+atb
        nout1=nout1+atn
        nout2=nout1+after
        nout3=nout2+after
        do 3001,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)
        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
3001        continue
        do 3000,ia=2,after
        ias=ia-1
        if (4*ias.eq.3*after) then
        if (isign.eq.1) then
                nin1=ia-after
                nout1=ia-atn
                do 3010,ib=1,before
                nin1=nin1+after
                nin2=nin1+atb
                nin3=nin2+atb
                nout1=nout1+atn
                nout2=nout1+after
                nout3=nout2+after
                do 3010,j=1,n1dfft
                r1=zin(1,j,nin1)
                s1=zin(2,j,nin1)
                r2=zin(2,j,nin2)
                s2=zin(1,j,nin2)
                r3=zin(1,j,nin3)
                s3=zin(2,j,nin3)
                r=r3 + r2
                s=s2 - s3
                zout(1,j,nout1) = r1 - r
                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
3010                continue
        else
                nin1=ia-after
                nout1=ia-atn
                do 3020,ib=1,before
                nin1=nin1+after
                nin2=nin1+atb
                nin3=nin2+atb
                nout1=nout1+atn
                nout2=nout1+after
                nout3=nout2+after
                do 3020,j=1,n1dfft
                r1=zin(1,j,nin1)
                s1=zin(2,j,nin1)
                r2=zin(2,j,nin2)
                s2=zin(1,j,nin2)
                r3=zin(1,j,nin3)
                s3=zin(2,j,nin3)
                r=r2 - r3
                s=s2 + s3
                zout(1,j,nout1) = r + r1
                zout(2,j,nout1) = s1 - s
                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
3020                continue
        endif
        else if (8*ias.eq.3*after) then
        if (isign.eq.1) then
                nin1=ia-after
                nout1=ia-atn
                do 3030,ib=1,before
                nin1=nin1+after
                nin2=nin1+atb
                nin3=nin2+atb
                nout1=nout1+atn
                nout2=nout1+after
                nout3=nout2+after
                do 3030,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=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
3030                continue
        else
                nin1=ia-after
                nout1=ia-atn
                do 3040,ib=1,before
                nin1=nin1+after
                nin2=nin1+atb
                nin3=nin2+atb
                nout1=nout1+atn
                nout2=nout1+after
                nout3=nout2+after
                do 3040,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=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
3040                continue
        endif
        else
        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)
        nin1=ia-after
        nout1=ia-atn
        do 3090,ib=1,before
        nin1=nin1+after
        nin2=nin1+atb
        nin3=nin2+atb