[Insight-developers] testing modified times of process objects

[Josh Cates]

Hi Will,

My question is a little more specific:  It seems that there are at least
two conditions that will cause Execute() to be invoked.  (1) A filter's
inputs (data) have changed.  (2) A filter's member variables (parameters)
have changed.  Given (1) but not (2), I am looking for a way to avoid the
penalty of re-initializing the filter (calculating coefficients, for
example) before executing.

Josh.


At 03:44 PM 9/20/00 -0400, Will Schroeder wrote:
>Hi Josh-
>
>The way it's supposed to work is that the filter superclasses will take 
>care of all of that for you, and only invoke Execute() when the filter is 
>out of date. For this to work properly, it's very important to use
>Set/Get 
>macros which take care of sending a Modified() to the filter if something 
>changes (or of course you can do that yourself).

>Will

At 03:07 PM 9/20/00 -0400, Josh Cates wrote:
>Hello folks,
>
>How can I test a filter to see if it has been modified since its
Execute()
>method was last called?
>
>For example say I want to do something like:
>
>  MyFilterClass::Execute()
>  {
>    if ( this->HasBeenModifiedSinceLastExecuteCall() )
>    {
>      this->RecalculateSomeFilterParameters();
>    }
>
>    Filter();
>  }

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 Josh Cates			
 Dept. of Electrical Engineering	
 University of Tennessee, Knoxville
 Email: jecates at utk.edu
 Phone: (865) 974-0694
 URL:   www.cs.utk.edu/~cates
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