[Insight-developers] Initialization question

[Hans Johnson]

I was reviewing the code in itkImageBase and I think I found a possible
un-initialized memory location.

Should line 176 be change to:
scale.Fill(0.0);
In order to ensure that the matrix is has zeros on the off diagonal
locations?  Or is it guaranteed that the constructor for itkMarix will zero
out all the memory locations?

If the constructor does zero out the memory, then a comment to that effect
would be nice.  This just did not look correct since in most places when
declaring a multi-element entity where only some of the elements are
touched, it is common to have the myvar.Fill(0.0) immediately after the
declaration.


Hans

169 
//--------------------------------------------------------------------------
--
170 template<unsigned int VImageDimension>
171 void
172 ImageBase<VImageDimension>
173 ::ComputeIndexToPhysicalPointMatrices()
174 {
175   DirectionType scale;
176 
177   for (unsigned int i=0; i < VImageDimension; i++)
178     {
179     if (this->m_Spacing[i] == 0.0)
180       {
181       itkExceptionMacro("A spacing of 0 is not allowed: Spacing is " <<
this->m_Spacing);
182       }
183     scale[i][i] = this->m_Spacing[i];
184     }
185 
186   if (vnl_determinant(this->m_Direction.GetVnlMatrix()) == 0.0)
187     {
188     itkExceptionMacro(<< "Bad direction, determinant is 0. Direction is
" << this->m_Direction);
189     }
190 
191   this->m_IndexToPhysicalPoint = this->m_Direction * scale;
192   this->m_PhysicalPointToIndex = m_IndexToPhysicalPoint.GetInverse();
193 
194   this->Modified();
195 }

-- 
Hans J. Johnson, Ph.D.
Hans-johnson at uiowa.edu

278 GH
The University of Iowa
Iowa City, IA 52241
(319) 353 8587



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