[Insight-users] Walking off the end of an array.

[Bill Lorensen]

Ooops, I see that VNL_CONFIG_CHECK_BOUNDS is ON by default.

Bill

On Sat, Jun 6, 2009 at 12:17 PM, Bill Lorensen<bill.lorensen at gmail.com> wrote:
> I looked at the vnl_vector.h code and assert checking is only on for
> operator() #if VNL_CONFIG_CHECK_BOUNDS. Alsoin put(), checking is only
> on if #ifdef ERROR_CHECKING
>
> Maybe we should consider setting these if building Debug.
>
> Bill
>
> On Sat, Jun 6, 2009 at 10:23 AM, Mike
> Jackson<mike.jackson at bluequartz.net> wrote:
>> Yep. I followed the hierarchy all way back to the vnl_vector class and
>> so change my code a bit:
>>
>> when I print the value of the "size" of the array I get 2. So I tried
>> the following code and it seemed to let me set the value without
>> asserting during execution.
>>
>>
>> metricParams(200) = 0.0;
>> metricParams.put(200, 0.0);
>>
>> I made sure I was building with a debug build but I still do not get
>> an assert or error or anything that I would assume I would get when
>> running the code. Dunno.
>>
>> Mike
>>
>> On Sat, Jun 6, 2009 at 9:54 AM, Luis Ibanez<luis.ibanez at kitware.com> wrote:
>>>
>>> Hi Mike,
>>>
>>> The type used by the Metric for the array of transform parameters
>>> is ultimately an itk::Array<double>.
>>>
>>> You will find it in:
>>>
>>> Insight/Code/Common/itkTransformBase.h  line  49
>>>
>>>   /** Type of the input parameters. */
>>>   typedef  Array< double >           ParametersType;
>>>
>>>
>>> The code of the itkArray itself does not have assertions,
>>> nor error checking when accessing the elements with
>>> the operator[].
>>>
>>> The itkArray derives from the vnl_vector, which indeed
>>> has some of these assertions, but they are in the
>>>
>>>    operator()   method,
>>>
>>> not in the
>>>
>>>     operator[]  method.
>>>
>>> Therefore, you will have error checking if you use
>>>
>>>     metricParams(3) = 56;
>>>
>>> but not if you use
>>>
>>>     metricParams[3] = 56;
>>>
>>>
>>> --
>>>
>>>
>>>    Regards,
>>>
>>>
>>>         Luis
>>>
>>>
>>> -------------------------------------------------------------------------------------------------------------
>>> On Sat, Jun 6, 2009 at 9:33 AM, Mike Jackson <mike.jackson at bluequartz.net>
>>> wrote:
>>>>
>>>> While running some code I kept getting some asserts from the HDF5
>>>> library that I am using when my program exited. Turns out that I had
>>>> something like this in my own code:
>>>>
>>>>
>>>>
>>>> namespace R3D
>>>> {
>>>>  namespace Detail
>>>>  {
>>>>    const unsigned int Dimension = 2;
>>>>  }
>>>> }
>>>>
>>>> typedef   unsigned char  PixelType;
>>>> typedef itk::Image<PixelType, R3D::Detail::Dimension>
>>>>  ImageType;
>>>> typedef itk::MeanSquaresImageToImageMetric<  ImageType, ImageType >
>>>>  MetricType;
>>>> MetricType::TransformParametersType metricParams(R3D::Detail::Dimension);
>>>>
>>>>
>>>> metricParams[0] = scale;
>>>> metricParams[1] = 0.0;
>>>> metricParams[2] = 0.0;
>>>> metricParams[3] = 0.0;
>>>>
>>>> Turns out there are only 2 parameters for the metricParams array and
>>>> so I guess I was walking off the end of then array and assigning data
>>>> to memory locations in the HDF5 library area.
>>>>
>>>> Turns out I was using the non-boundary checking version of those
>>>> calls. I should have been doing something like:
>>>> metricParams(2) = 0.0;
>>>> metricParams.put(2, 0.0);
>>>>
>>>> So I tried those fully expecting an assert to happen by my code
>>>> completes successfully now. I compiled ITK in debug mode along with my
>>>> code. Is there something else that needs to be done in order to enable
>>>> these asserts or boundary checking? I am still new to ITK and so I
>>>> would like to have the safety net.
>>>>
>>>> Thanks
>>>> Mike Jackson
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>