Checked in patch for derivatives of bessel_k function
Subject: Checked in patch for derivatives of bessel_k function
From: Billinghurst, David (CALCRTS)
Date: Thu, 29 Jan 2004 10:33:59 +1100
I have just checked in a one line patch to bessel.lisp to correct
the derivatives of bessel_k functions.
--- src/bessel.lisp 4 Aug 2003 17:04:14 -0000 1.24
+++ src/bessel.lisp 28 Jan 2004 23:26:38 -0000
@@ -1113,7 +1113,7 @@
((mtimes simp) -1
((%derivative simp) ((%bessel_i simp) n x) n 1)))))
((mplus simp)
- ((mtimes) -1 ((%bessel_k) n x))
+ ((mtimes) -1 ((%bessel_k) ((mplus) -1 n) x))
((mtimes) -1 n ((mexpt) x -1)
((%bessel_k) n x))))
grad)
The old behaviour was
(C1) diff(bessel_k(0,x),x);
(D1) - BESSEL_K(0, x)
(C2) diff(bessel_k(1,x),x);
BESSEL_K(1, x)
(D2) - -------------- - BESSEL_K(1, x)
x
and the new behavior is
(C1) diff(bessel_k(0,x),x);
(D1) - BESSEL_K(1, x)
(C2) diff(bessel_k(1,x),x);
BESSEL_K(1, x)
(D2) - -------------- - BESSEL_K(0, x)
x