SUBROUTINE MFFTC5(C,FAC)**   PURPOSE:*       ELEMENTARY COOLEY-TUKEY RADIX 5 STEP APPLIED TO A VECTOR-OF*       VECTORS-OF-COMPLEX C[IVS,NV [IES,NE]].*       SEE REF.[1] FOR NOTATIONS.*       THIS ROUTINE CAN BE USED ONLY BY ROUTINE MFFTIV, WHICH CONTROLS*       ITS OPERATION THROUGH THE MFFTPA COMMON**   DUMMY ARGUMENTS :**   C   ARRAY BEING FOURIER  TRANSFORMED*   FAC PHASE FACTORS, PREPARED BY MFFTP; NOT MODIFIED IN OUTPUT*      COMMON /MFFTPA/  IMS,IVS,IES,NM,NV,NE,MX,LX,MLIM,MSTEP,LLIM,LSTEP,     $ NUSTEP,IVLIM,ILIM,MD2LIM,LD2LIM      INTEGER NUSTEP      COMPLEX C(0:NUSTEP-1,0:4),FAC(0:*)      COMPLEX T1,T2,T3,T4,T5,F1,F2,F3,F4      REAL SIN72,RAD5D4,S36D72      PARAMETER (     $ SIN72 =  9.51056516295153572116439333E-1,     $ RAD5D4 =  5.59016994374947424102293417E-1,     $ S36D72 =  6.18033988749894848204586834E-1 )*..  LAM > 0          LAMF=MX          DO 100 LAM=LSTEP,LLIM,LSTEP            F1=FAC(LAMF)            F2=FAC(2*LAMF)            F3=FAC(3*LAMF)            F4=FAC(4*LAMF)            DO 90 MU=LAM,LAM+MLIM,MSTEP              DO 80 I=MU,MU+ILIM,IES                T1=C(I,1)*F1+C(I,4)*F4                T2=C(I,2)*F2+C(I,3)*F3                T3=(C(I,1)*F1-C(I,4)*F4)*SIN72                T4=(C(I,2)*F2-C(I,3)*F3)*SIN72                T5=T1+T2                T1=RAD5D4*(T1-T2)                T2=C(I,0)-0.25*T5                C(I,0)=C(I,0)+T5                T5=T2+T1                T2=T2-T1                T1=T3+S36D72*T4                T3=S36D72*T3-T4                C(I,1)=T5+CMPLX(-AIMAG(T1),REAL(T1))                C(I,4)=T5-CMPLX(-AIMAG(T1),REAL(T1))                C(I,2)=T2+CMPLX(-AIMAG(T3),REAL(T3))                C(I,3)=T2-CMPLX(-AIMAG(T3),REAL(T3))80            CONTINUE90          CONTINUE            LAMF=LAMF+MX100       CONTINUE *.. LAM=0          DO 92 MU=0,MLIM,MSTEP            DO 82 I=MU,MU+ILIM,IES              T1=C(I,1)+C(I,4)              T2=C(I,2)+C(I,3)              T3=(C(I,1)-C(I,4))*SIN72              T4=(C(I,2)-C(I,3))*SIN72              T5=T1+T2              T1=RAD5D4*(T1-T2)              T2=C(I,0)-0.25*T5              C(I,0)=C(I,0)+T5              T5=T2+T1              T2=T2-T1              T1=T3+S36D72*T4              T3=S36D72*T3-T4              C(I,1)=T5+CMPLX(-AIMAG(T1),REAL(T1))              C(I,4)=T5-CMPLX(-AIMAG(T1),REAL(T1))              C(I,2)=T2+CMPLX(-AIMAG(T3),REAL(T3))              C(I,3)=T2-CMPLX(-AIMAG(T3),REAL(T3))82          CONTINUE92        CONTINUE      END