From bug-octave-request at bevo dot che dot wisc dot edu  Thu Mar 29 15:01:54 2001
Subject: Incorrect parameters passed to besselh functions
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Thomas Stuart <tstuart at ing dot sun dot ac dot za>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Thu, 29 Mar 2001 15:01:36 -0600

On 29-Mar-2001, Thomas Stuart <tstuart at ing dot sun dot ac dot za> wrote:

| I found this bug, and I think I fixed it, but I didn't understand
| most of the code, so please don't take my word for it. Any comments
| would be appreciated!

Here is the change I made:

Index: besselj.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/src/DLD-FUNCTIONS/besselj.cc,v
retrieving revision 1.10
diff -u -r1.10 besselj.cc
--- besselj.cc	2000/02/03 10:21:55	1.10
+++ besselj.cc	2001/03/29 20:49:34
 at @ -332,17 +332,15 @@
 
   int nargin = args.length ();
 
-  int kind = 1;
-
   if (nargin == 2)
     {
       retval = do_bessel (BESSEL_H1, "besselh", args, nargout);
     }
   else if (nargin == 3 || nargin == 4)
     {
-      double d_kind = args(1).double_value ();
+      int kind = args(1).int_value ();
 
-      if (! error_state && D_NINT (d_kind) == d_kind)
+      if (! error_state)
 	{
 	  octave_value_list tmp_args;
 
Originally, I think the intent was to convert d_kind to an int before
using it.  The int_value method is relatively new, which is probably
why it was not used originally.

|    >>besselh(0,2,1)
| 
| 
|    ans = 0.765198 + 0.088257i
|    >> %The correct answer (from MATLAB)
| 
|    ans  =
|                0.44005 + 0.78121i

Are you sure this is correct?  With the change, I see

  octave:1> besselh(0,1,1)
  ans = 0.765198 + 0.088257i
  octave:2> besselh(0,2,1)
  ans = 0.765198 - 0.088257i

I think the answer from Matlab that you show above is actually for
besselh (1, 2, 1).

jwe



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