Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,52 @@
+      SUBROUTINE drealft(data,n,isign)
+      INTEGER isign,n
+      DOUBLE PRECISION data(n)
+CU    USES dfour1
+      INTEGER i,i1,i2,i3,i4,n2p3
+      DOUBLE PRECISION c1,c2,h1i,h1r,h2i,h2r,wis,wrs
+      DOUBLE PRECISION theta,wi,wpi,wpr,wr,wtemp
+      theta=3.141592653589793d0/dble(n/2)
+      c1=0.5d0
+      if (isign.eq.1) then
+        c2=-0.5d0
+        call dfour1(data,n/2,+1)
+      else
+        c2=0.5d0
+        theta=-theta
+      endif
+      wpr=-2.0d0*sin(0.5d0*theta)**2
+      wpi=sin(theta)
+      wr=1.0d0+wpr
+      wi=wpi
+      n2p3=n+3
+      do 11 i=2,n/4
+        i1=2*i-1
+        i2=i1+1
+        i3=n2p3-i2
+        i4=i3+1
+        wrs=wr
+        wis=wi
+        h1r=c1*(data(i1)+data(i3))
+        h1i=c1*(data(i2)-data(i4))
+        h2r=-c2*(data(i2)+data(i4))
+        h2i=c2*(data(i1)-data(i3))
+        data(i1)=h1r+wrs*h2r-wis*h2i
+        data(i2)=h1i+wrs*h2i+wis*h2r
+        data(i3)=h1r-wrs*h2r+wis*h2i
+        data(i4)=-h1i+wrs*h2i+wis*h2r
+        wtemp=wr
+        wr=wr*wpr-wi*wpi+wr
+        wi=wi*wpr+wtemp*wpi+wi
+11    continue
+      if (isign.eq.1) then
+        h1r=data(1)
+        data(1)=h1r+data(2)
+        data(2)=h1r-data(2)
+      else
+        h1r=data(1)
+        data(1)=c1*(h1r+data(2))
+        data(2)=c1*(h1r-data(2))
+        call dfour1(data,n/2,-1)
+      endif
+      return
+      END