- added inverse diagonal extraction function
- added a function for checking of supported operations


git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16796 25697fe4-d644-49b8-9d30-be5465f2adf3
- implemented get/set diagonal and gradient evaluation for abstract matrix
  Hessians


git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16797 25697fe4-d644-49b8-9d30-be5465f2adf3
- Experimental correction of zigzag-like small drifts, don't sure it is better, than current drift correction

git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16798 25697fe4-d644-49b8-9d30-be5465f2adf3
- Actually add zigzag.c

git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16799 25697fe4-d644-49b8-9d30-be5465f2adf3
- Removed incomplete code from previous commits

git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16800 25697fe4-d644-49b8-9d30-be5465f2adf3
- trying to also implement too_small_param_change() for abstract matrix
  Hessians


git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16801 25697fe4-d644-49b8-9d30-be5465f2adf3