[vtkusers] Bug in vtkDataArrayTemplate.txx?

[David C Thompson]

On Thu, 2007-09-20 at 23:19 -0400, Berk Geveci wrote:
> I object :-) Modified() is a very, very expansive call and calling it
> from DataChanged() which gets called from SetTuple() etc. will cause
> serious penalty problems.

Doh! I should have guessed.

> Modified() was left out of those methods on
> purpose. Modified() is expansive because it uses a mutex (look at
> vtkTimeStamp.cxx). This change would cause tight loops to execute an
> order of magnitude slower. However, I would think that if the user
> called DataChanged(), it should call Modified(). Maybe
> vtkDataArrayTemplate should call something else internally.

Some of the calls (like Initialize()?) might benefit from a
this->Modified() after the call to this->DataChanged(). Another
possibility is adding a member to vtkDataArrayTemplate named, for
example, Altered and using it to bypass checks on MTime() when computing
the range of some component. Setting Altered=1 in DataChanged() would
not be expensive and could even take the place of the code that deletes
the lookup table (by pushing lookup table deletion to places where it is
requested, although that might be an intrusive change).

Or I could just drop it. :-) I only mentioned it because I noticed it
while I was debugging a test (the information object for abstract array
stuff). A feature is a feature is a feature...

	David

> 
> On 9/20/07, David C Thompson <dcthomp at sandia.gov> wrote:
> > Hi all,
> >
> >         I believe vtkDataArrayTemplate<T>::DataChanged() should invoke
> > this->Modified(). Otherwise, RemoveTuple, SetArray, Initialize, and
> > several other methods will not result in the MTime of the array being
> > updated. Since this MTime is used when comparing the array modification
> > time to the cached component ranges, it can lead to the array bounds
> > being incorrect. I have verified this behavior with a modified
> > Common/Testing/Cxx/TestDataArray.cxx (attached).
> >
> >         If no one objects, I will add the call to Modified() and check in the
> > modified version of Common/Testing/Cxx/TestDataArray.cxx to prevent
> > regressions.
> >
> >         David
> >
> > #include "vtkIntArray.h"
> > #include "vtkDoubleArray.h"
> >
> > int TestDataArray(int,char *[])
> > {
> >   double range[2];
> >   vtkIntArray* array = vtkIntArray::New();
> >   array->GetRange( range, 0 );
> >   if ( range[0] != VTK_DOUBLE_MAX || range[1] != VTK_DOUBLE_MIN )
> >     {
> >     cerr << "Getting range of empty array failed, min: " << range[0] << " max: " << range[1] << "\n";
> >     array->Delete();
> >     return 1;
> >     }
> >   int cc;
> >   for ( cc = 0; cc < 10; cc ++ )
> >     {
> >     array->InsertNextTuple1(cc);
> >     }
> >   array->RemoveFirstTuple();
> >   array->RemoveTuple(3);
> >   array->RemoveTuple(4);
> >   array->GetRange( range, 0 );
> >   if ( range[0] != 1. || range[1] != 9. )
> >     {
> >     cerr << "Getting range of array {1,2,3,5,7,8,9} failed, min: " << range[0] << " max: " << range[1] << "\n";
> >     array->Delete();
> >     return 1;
> >     }
> >   array->RemoveLastTuple();
> >   array->GetRange( range, 0 );
> >   if ( range[0] != 1. || range[1] != 8. )
> >     {
> >     cerr << "Getting range of array {1,2,3,5,7,8} failed, min: " << range[0] << " max: " << range[1] << "\n";
> >     array->Delete();
> >     return 1;
> >     }
> >   int ca[] = { 1, 2, 3, 5, 7, 8 };
> >   cout << "Array:";
> >   for ( cc = 0; cc < array->GetNumberOfTuples(); ++cc )
> >     {
> >     if ( array->GetTuple1(cc) != ca[cc] )
> >       {
> >       cerr << "Problem with array: " << array->GetTuple1(cc) << " <> " << ca[cc] << endl;
> >       return 1;
> >       }
> >     cout << " " << array->GetTuple1(cc);
> >     }
> >   cout << endl;
> >   array->Delete();
> >
> >   vtkDoubleArray* farray = vtkDoubleArray::New();
> >   farray->SetNumberOfComponents(3);
> >   for ( cc = 0; cc < 10; cc ++ )
> >     {
> >     farray->InsertNextTuple3( cc + 0.1, cc + 0.2, cc + 0.3);
> >     }
> >   farray->RemoveFirstTuple();
> >   farray->RemoveTuple(3);
> >   farray->RemoveTuple(4);
> >   farray->RemoveLastTuple();
> >   cout << "Array:";
> >   for ( cc = 0; cc < farray->GetNumberOfTuples(); ++cc )
> >     {
> >     double* fa = farray->GetTuple3(cc);
> >     double fc[3];
> >     fc[0] = ca[cc] + .1;
> >     fc[1] = ca[cc] + .2;
> >     fc[2] = ca[cc] + .3;
> >     for (int i = 0; i < 3; i++)
> >       {
> >       if (fa[i] != fc[i])
> >         {
> >         cerr << "Problem with array: " << fa[i] << " <> " << fc[i] << endl;
> >         return 1;
> >         }
> >       }
> >     cout << " " << fa[0] << "," << fa[1] << "," << fa[2];
> >     }
> >   cout << endl;
> >   farray->Delete();
> >   return 0;
> > }
> >
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