Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,53 @@
+      FUNCTION rtsafe(funcd,x1,x2,xacc)
+      INTEGER MAXIT
+      REAL rtsafe,x1,x2,xacc
+      EXTERNAL funcd
+      PARAMETER (MAXIT=100)
+      INTEGER j
+      REAL df,dx,dxold,f,fh,fl,temp,xh,xl
+      call funcd(x1,fl,df)
+      call funcd(x2,fh,df)
+      if((fl.gt.0..and.fh.gt.0.).or.(fl.lt.0..and.fh.lt.0.))pause
+     *'root must be bracketed in rtsafe'
+      if(fl.eq.0.)then
+        rtsafe=x1
+        return
+      else if(fh.eq.0.)then
+        rtsafe=x2
+        return
+      else if(fl.lt.0.)then
+        xl=x1
+        xh=x2
+      else
+        xh=x1
+        xl=x2
+      endif
+      rtsafe=.5*(x1+x2)
+      dxold=abs(x2-x1)
+      dx=dxold
+      call funcd(rtsafe,f,df)
+      do 11 j=1,MAXIT
+        if(((rtsafe-xh)*df-f)*((rtsafe-xl)*df-f).ge.0..or. abs(2.*
+     *f).gt.abs(dxold*df) ) then
+          dxold=dx
+          dx=0.5*(xh-xl)
+          rtsafe=xl+dx
+          if(xl.eq.rtsafe)return
+        else
+          dxold=dx
+          dx=f/df
+          temp=rtsafe
+          rtsafe=rtsafe-dx
+          if(temp.eq.rtsafe)return
+        endif
+        if(abs(dx).lt.xacc) return
+        call funcd(rtsafe,f,df)
+        if(f.lt.0.) then
+          xl=rtsafe
+        else
+          xh=rtsafe
+        endif
+11    continue
+      pause 'rtsafe exceeding maximum iterations'
+      return
+      END