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 @@
+      SUBROUTINE laguer(a,m,x,its)
+      INTEGER m,its,MAXIT,MR,MT
+      REAL EPSS
+      COMPLEX a(m+1),x
+      PARAMETER (EPSS=2.e-7,MR=8,MT=10,MAXIT=MT*MR)
+      INTEGER iter,j
+      REAL abx,abp,abm,err,frac(MR)
+      COMPLEX dx,x1,b,d,f,g,h,sq,gp,gm,g2
+      SAVE frac
+      DATA frac /.5,.25,.75,.13,.38,.62,.88,1./
+      do 12 iter=1,MAXIT
+        its=iter
+        b=a(m+1)
+        err=abs(b)
+        d=cmplx(0.,0.)
+        f=cmplx(0.,0.)
+        abx=abs(x)
+        do 11 j=m,1,-1
+          f=x*f+d
+          d=x*d+b
+          b=x*b+a(j)
+          err=abs(b)+abx*err
+11      continue
+        err=EPSS*err
+        if(abs(b).le.err) then
+          return
+        else
+          g=d/b
+          g2=g*g
+          h=g2-2.*f/b
+          sq=sqrt((m-1)*(m*h-g2))
+          gp=g+sq
+          gm=g-sq
+          abp=abs(gp)
+          abm=abs(gm)
+          if(abp.lt.abm) gp=gm
+          if (max(abp,abm).gt.0.) then
+            dx=m/gp
+          else
+            dx=exp(cmplx(log(1.+abx),float(iter)))
+          endif
+        endif
+        x1=x-dx
+        if(x.eq.x1)return
+        if (mod(iter,MT).ne.0) then
+          x=x1
+        else
+          x=x-dx*frac(iter/MT)
+        endif
+12    continue
+      pause 'too many iterations in laguer'
+      return
+      END