[Vxl-users] Proposed Patch for Bug in vnl_lsqr.cxx

[Brian A. <vx...@br...>]

Hello,

I was lead into searching for a bug in my program for quite a while by
an inconsistency in vnl_lsqr.cxx. The minimize function returns an int,
and there is a function translate_return_code that is
documented as "translating the return code into a string". Now vnl_lsqr
returns always 0 with the comment, that the return code is not needed.

There is an additional function diagnose_outcome, that accesses the
saved return code and uses this with translate_return_code. I propose
that either the documentation is changed, or the following patch
included:

Index: vnl_lsqr.cxx
===================================================================
RCS file: /cvsroot/vxl/vxl/core/vnl/algo/vnl_lsqr.cxx,v
retrieving revision 1.20
diff -r1.20 vnl_lsqr.cxx
96c96,99
<   return 0; // return value not used
---
>   // We should return the return code, as translate_return_code is public and
>   // it is very misleading that the return code from this function can't be fed
>   // into translate_return_code. (Brian Amberg)
>   return return_code_;
Index: vnl_lsqr.h
===================================================================
RCS file: /cvsroot/vxl/vxl/core/vnl/algo/vnl_lsqr.h,v
retrieving revision 1.20
diff -r1.20 vnl_lsqr.h
47c47,48
<   // Return code may be translated with translate_return_code().
---
>   // Return code may be translated with translate_return_code(), or the result of the 
>   // minimization may be printed in more detail with diagnose_outcome()
56a58,62
>   //: Get the return code for the last minimization
>   inline int return_code() const { return return_code_; }
> 
> 
> 

best regards,

Brian Amberg

-- 
Brian Amberg
http://ruby.brian-amberg.de/