MATLAB: How to change the value of the HEAVISIDE function from NaN to 1/2 when in Symbolic Math Toolbox 3.2 (R2007a)

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The HEAVISIDE function is desigedn to return NaN for x== 0. I would like the HEAVISIDE function to return 1/2 instead.
When I execute:
f=heaviside(sym('0'))
The ouput is:
 f =
 NaN
How can I modify the output of 'heaviside(sym('0'))' to 1/2 instead of NaN?

Best Answer

The value of heaviside(sym('0')) can be altered form NaN to any value (say 1/2). This can be achieved by modifying the status of 'heaviside()' in Maple, which is 'undefined' by default, in the Maple Kernel.
You can do this as follows:
At the MATLAB command prompt, type:
maple('At_zero_return_one_half := proc(f,X)     if f = Heaviside and X[1] = 0 then   NumericStatus(invalid_operation=false);1/2;else undefined;end if;end proc:');
maple('NumericEventHandler( invalid_operation = At_zero_return_one_half ): forget(Heaviside):');
This will assign the value 1/2 to heaviside(0) in the Maple kernel.
You can verify that you obtain the expected behavior:
   f=heaviside(sym('0'))
returns:
 f =
 1/2
Once you have completed the task, if you desire to clear these settings on HEAVISIDE, please type:
maple restart
to restart Maple
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