Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,31 @@
+      SUBROUTINE gauleg(x1,x2,x,w,n)
+      INTEGER n
+      REAL x1,x2,x(n),w(n)
+      DOUBLE PRECISION EPS
+      PARAMETER (EPS=3.d-14)
+      INTEGER i,j,m
+      DOUBLE PRECISION p1,p2,p3,pp,xl,xm,z,z1
+      m=(n+1)/2
+      xm=0.5d0*(x2+x1)
+      xl=0.5d0*(x2-x1)
+      do 12 i=1,m
+        z=cos(3.141592654d0*(i-.25d0)/(n+.5d0))
+1       continue
+          p1=1.d0
+          p2=0.d0
+          do 11 j=1,n
+            p3=p2
+            p2=p1
+            p1=((2.d0*j-1.d0)*z*p2-(j-1.d0)*p3)/j
+11        continue
+          pp=n*(z*p1-p2)/(z*z-1.d0)
+          z1=z
+          z=z1-p1/pp
+        if(abs(z-z1).gt.EPS)goto 1
+        x(i)=xm-xl*z
+        x(n+1-i)=xm+xl*z
+        w(i)=2.d0*xl/((1.d0-z*z)*pp*pp)
+        w(n+1-i)=w(i)
+12    continue
+      return
+      END