Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,35 @@
+      SUBROUTINE stoerm(y,d2y,nv,xs,htot,nstep,yout,derivs)
+      INTEGER nstep,nv,NMAX
+      REAL htot,xs,d2y(nv),y(nv),yout(nv)
+      EXTERNAL derivs
+      PARAMETER (NMAX=50)
+CU    USES derivs
+      INTEGER i,n,neqns,nn
+      REAL h,h2,halfh,x,ytemp(NMAX)
+      h=htot/nstep
+      halfh=0.5*h
+      neqns=nv/2
+      do 11 i=1,neqns
+        n=neqns+i
+        ytemp(n)=h*(y(n)+halfh*d2y(i))
+        ytemp(i)=y(i)+ytemp(n)
+11    continue
+      x=xs+h
+      call derivs(x,ytemp,yout)
+      h2=h*h
+      do 13 nn=2,nstep
+        do 12 i=1,neqns
+          n=neqns+i
+          ytemp(n)=ytemp(n)+h2*yout(i)
+          ytemp(i)=ytemp(i)+ytemp(n)
+12      continue
+        x=x+h
+        call derivs(x,ytemp,yout)
+13    continue
+      do 14 i=1,neqns
+        n=neqns+i
+        yout(n)=ytemp(n)/h+halfh*yout(i)
+        yout(i)=ytemp(i)
+14    continue
+      return
+      END