MATLAB: Do I receive unexpected results when using the ‘truncate’ option with the MODRED function from the Control Systems Toolbox 6.1 (R14SP1)

Control System Toolboxmodelmodredreductiontruncate

I am using the MODRED function's 'truncate' option in the Control Systems Toolbox 6.1 (R14SP1). When I execute the following commands to reduce the number of states:
sys = ss(diag([-1, -2, -3]), [1; 2; 3], [1 2 1 ], 0); 
sys_r = modred(sys, [3], 'Truncate');
sys_r.d
the following result is returned:
 ans =
      1
The value returned should be 0.

Best Answer

This bug has been fixed in the Control Systems Toolbox 6.2 (R14SP2). If you are using a previous version, read the following:
We have verified that there is a bug in the Control Systems Toolbox 6.1 (R14SP1) in the way that the MODRED function handles the 'Truncate' option when spelled with an uppercase "T".
To work around this issue, use the 'truncate' option spelled with a lowercase "t".
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