Initial commit

2016-02-03 18:52:05 +00:00
commit d40505e161
507 changed files with 91383 additions and 0 deletions
@@ -0,0 +1,32 @@
+      FUNCTION bessi(n,x)
+      INTEGER n,IACC
+      REAL bessi,x,BIGNO,BIGNI
+      PARAMETER (IACC=40,BIGNO=1.0e10,BIGNI=1.0e-10)
+CU    USES bessi0
+      INTEGER j,m
+      REAL bi,bim,bip,tox,bessi0
+      if (n.lt.2) pause 'bad argument n in bessi'
+      if (x.eq.0.) then
+        bessi=0.
+      else
+        tox=2.0/abs(x)
+        bip=0.0
+        bi=1.0
+        bessi=0.
+        m=2*((n+int(sqrt(float(IACC*n)))))
+        do 11 j=m,1,-1
+          bim=bip+float(j)*tox*bi
+          bip=bi
+          bi=bim
+          if (abs(bi).gt.BIGNO) then
+            bessi=bessi*BIGNI
+            bi=bi*BIGNI
+            bip=bip*BIGNI
+          endif
+          if (j.eq.n) bessi=bip
+11      continue
+        bessi=bessi*bessi0(x)/bi
+        if (x.lt.0..and.mod(n,2).eq.1) bessi=-bessi
+      endif
+      return
+      END