[Insight-users] Failed to allocate memory

[Luis Ibanez]

Hi Sajendra,

I'm confused with your last email.

In your previous email you describe that you expected to find 2.5Gb
of memory allocation.

The amount of 2.5Gb is consistent with what we think the Demons filter
will require in this case.

This amount of memory (2.5Gb) cannot be allocated in a standard
Windows 32 system. The limit of memory for a single process in
a Window 32 system is 2Gb.


Could you please clarify what you mean by:

  1) Expected memory usage
  2) Observer memory usage


and what number of GigaBytes are you finding for both items ?


   Thanks


      Luis



--------------------------------
Nithiananthan, Sajendra wrote:
> Luis,
> 
> So the memory usage I observed was much larger than would be expected (see
> below).
> As I mentioned, I was importing the images into ITK, so the increased memory
> usage might be a problem further up the pipeline.
> 
> -Sajendra N.
> 
> 
>>-----Original Message-----
>>From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
>>
>>Hi Sajendra,
>>
>>Yes,
>>2.5 Gb sounds about right for the amount of RAM memory that
>>you would need for running this filter.
>>
>>Note however that a process in Windows 32bits system cannot
>>allocate more than 2Gb of RAM.
>>    Regards,
>>
>>        Luis
>>-------------------------------
>>Nithiananthan, Sajendra wrote:
>>
>>>Luis,
>>>
>>>The pixel type is "float", 4 bytes/pixel. So the image size 
>>
>>is approximately
>>
>>>100 million pixels, or 400MB.
>>>I chose to represent the deformation field with a vector of 
>>
>>floats, so they
>>
>>>are three times as big, or about 1.2GB.
>>>Specifically:
>>>    const unsigned int DIMENSION = 3;
>>>    typedef itk::Image<float, DIMENSION>	ImageType;
>>>    //representation of the deformation field:
>>>    typedef itk::Vector<float, DIMENSION>   VectorPixelType;
>>>    typedef itk::Image<VectorPixelType, DIMENSION>  
>>
>>DeformationFieldType;
>>
>>>So to represent the fixed image, moving image, deformation 
>>
>>field, and output
>>
>>>image, I would expect usage about 2.5GB?
>>>
>>>-Sajendra
>>>
>>>
>>>
>>>
>>>
>>>>-----Original Message-----
>>>>From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
>>>>Subject: Re: [Insight-users] Failed to allocate memory
>>>>
>>>>Hi Sajendra,
>>>>
>>>>What was the image size (in pixels) ?
>>>>
>>>>From a 400Mb image, if we assume that you are using "signed short"
>>>>as pixel type, then we are probably talking about:
>>>>
>>>>                      200 Million pixels
>>>>
>>>>Demons will internally construct a deformation field with a 
>>
>>3D vector
>>
>>>>of doubles per pixel. That will be:
>>>>
>>>>              2e8 x 3 x 8 bytes = 4.9 Gigabytes.
>>>>
>>>>To this you will have to add the 400Mb of the output image.
>>>>
>>>>
>>>>Therefore your observed memory actually looks small for 
>>
>>this problem.
>>
>>>>
>>>>   Regards,
>>>>
>>>>
>>>>
>>>>      Luis
>>>>
>>>>
>>>>
>>>>-------------------------------
>>>>Nithiananthan, Sajendra wrote:
>>>>
>>>>
>>>>>I was in a situation similar to the OP, Zhihong, trying to 
>>>>
>>>>use ITK based
>>>>
>>>>
>>>>>Demons registration on larger images (~400MB). It failed 
>>>>
>>>>spectacularly  on
>>>>
>>>>
>>>>>32 bit Windows. Compiling and running on a 64 bit machine 
>>
>>solved the
>>
>>>>>problem.
>>>>>The peak memory was about 4.5 GB, which seems high (no 
>>>>
>>>>histogram matching or
>>>>
>>>>
>>>>>casting used). I had imported the images into ITK from VTK 
>>>>
>>>>so perhaps that
>>>>
>>>>
>>>>>explains some of the increased memory usage. Either way, it 
>>>>
>>>>did run well and
>>>>
>>>>
>>>>>gave me the results I would have expected (compared the 
>>>>
>>>>output for a smaller
>>>>
>>>>
>>>>>image to that from a 32bit machine). I will hopefully 
>>>>
>>>>confirm later that
>>>>
>>>>
>>>>>nothing strange is happening with memory usage.
>>>>>
>>>>>Thank you for your input
>>>>>-Sajendra
>>>>>
>>>>>
>>>>>
>>>
>>>
> 
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