Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,41 @@
+      SUBROUTINE gauher(x,w,n)
+      INTEGER n,MAXIT
+      REAL w(n),x(n)
+      DOUBLE PRECISION EPS,PIM4
+      PARAMETER (EPS=3.D-14,PIM4=.7511255444649425D0,MAXIT=10)
+      INTEGER i,its,j,m
+      DOUBLE PRECISION p1,p2,p3,pp,z,z1
+      m=(n+1)/2
+      do 13 i=1,m
+        if(i.eq.1)then
+          z=sqrt(float(2*n+1))-1.85575*(2*n+1)**(-.16667)
+        else if(i.eq.2)then
+          z=z-1.14*n**.426/z
+        else if (i.eq.3)then
+          z=1.86*z-.86*x(1)
+        else if (i.eq.4)then
+          z=1.91*z-.91*x(2)
+        else
+          z=2.*z-x(i-2)
+        endif
+        do 12 its=1,MAXIT
+          p1=PIM4
+          p2=0.d0
+          do 11 j=1,n
+            p3=p2
+            p2=p1
+            p1=z*sqrt(2.d0/j)*p2-sqrt(dble(j-1)/dble(j))*p3
+11        continue
+          pp=sqrt(2.d0*n)*p2
+          z1=z
+          z=z1-p1/pp
+          if(abs(z-z1).le.EPS)goto 1
+12      continue
+        pause 'too many iterations in gauher'
+1       x(i)=z
+        x(n+1-i)=-z
+        w(i)=2.d0/(pp*pp)
+        w(n+1-i)=w(i)
+13    continue
+      return
+      END