Initial commit

dataassim/math/numrec/f77_sources/shell.for

@@ -0,0 +1,24 @@
+      SUBROUTINE shell(n,a)
+      INTEGER n
+      REAL a(n)
+      INTEGER i,j,inc
+      REAL v
+      inc=1
+1     inc=3*inc+1
+      if(inc.le.n)goto 1
+2     continue
+        inc=inc/3
+        do 11 i=inc+1,n
+          v=a(i)
+          j=i
+3         if(a(j-inc).gt.v)then
+            a(j)=a(j-inc)
+            j=j-inc
+            if(j.le.inc)goto 4
+          goto 3
+          endif
+4         a(j)=v
+11      continue
+      if(inc.gt.1)goto 2
+      return
+      END