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2846 Views 7 Replies Latest reply: Mar 3, 2011 10:28 AM by DavidShaw RSS
DavidShaw Copper 4 posts since
Feb 24, 2011
Currently Being Moderated

Feb 24, 2011 2:10 PM

MathCAD 11

There is one characteristic of MathCAD 11 that I have made use of when writing my own C code functions.

The default parameter passing requires that the pointers to all the inputs be constant (const).

However, I was implementing an adaptive filter and I needed to see the resulting coefficients, so I called the routine as follows:

 

  LRESULT  Nlms(  COMPLEXARRAY * const Nlms,
                    COMPLEXARRAY * const H,
                    const COMPLEXARRAY * const X,
                    const COMPLEXARRAY * const Y,
                    const COMPLEXSCALAR * const Step,
                    const COMPLEXSCALAR * const Points
                    )

 

Not only could I see the resulting updates to the coefficients, but I could repeatedly press F9 over the function and re-run the same data over and over to get better and better results, sometimes while gradually adjusting to smaller and smaller step sizes.  This worked because subsequent calls used the coefficients starting at with results of the previous call.

 

Unfortunately, someone at MathSoft figured out that this door needed to be closed, and in subsequent versions of MatCAD such tricks no longer work.

 

The technique I use now is to append the coefficients to the end of the output from the adaptive filter, strip them off into a new vector, and then call a new copy of the function with the new coefficient vector.  Not a very satisfactory technique as one can appreciate.

 

I wonder if there is any equivalent game to my earlier technique that I can play to return to this idea in more recent versions?

 

David Shaw

  • MikeArmstrong Diamond 4,505 posts since
    Dec 3, 2008
    Currently Being Moderated
    Feb 24, 2011 2:16 PM (in response to DavidShaw)
    Re: MathCAD 11

    What version of Mathcad are you now running.

     

    A worksheet would be helpful to get a clear idea of what you are doing.

     

    Mike

      • MikeArmstrong Diamond 4,505 posts since
        Dec 3, 2008
        Currently Being Moderated
        Feb 25, 2011 1:28 AM (in response to DavidShaw)
        Re: MathCAD 11

        A lot of users have had problem with worksheets that worked in version 11 and not in the later releases. I'm afraid that's the way it is. I would suggest putting M11 back onto your 'semi-retired' machine.

         

        Mike

          • MikeArmstrong Diamond 4,505 posts since
            Dec 3, 2008
            Currently Being Moderated
            Feb 26, 2011 1:14 PM (in response to DavidShaw)
            Re: MathCAD 11

            How well does MathCAD 11 work under Windows 7?

            I don't personally know. I have heard of issues, but people have found work around's as described above.

            How do I go about get the necessary activation code to get MathCAD 11 working on my new Windows 7 machine?

            I take it you have a copy of Mathcad 11? If so, you could contact the Mathcad license and Install team.

             

            mathcadlicensing@ptc.com.

             

            Mike

          • StuartBruff Platinum 4,830 posts since
            Jun 1, 2007
            Currently Being Moderated
            Feb 26, 2011 3:14 PM (in response to DavidShaw)
            Re: MathCAD 11

            David Shaw wrote:

             

            How well does MathCAD 11 work under Windows 7?

            How do I go about get the necessary activation code to get MathCAD 11 working on my new Windows 7 machine?

             

            Thanks,

            David Shaw

            Dave,

             

            I'm running M11 under Windows 7 Ultimate (32-bit) without any problems (or none that I've noticed anyway).   And that's in parallel with both M14 and now M15/Prime.

             

            Stuart

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