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Hi Mike,

Great. The attached doc has examples of two definite integrals. In the first one it is assumed that f(t) has already been calculated from t=t1 to t=t2 and y (a single value) is then computed. In the second one, the value of y(t) is updated as time progresses, so that f(t) and y(t) would be computed at the same time. This requires that the value of this integral up until the previous time step, y(t-dt), is stored and the new increment f(t*).dt is then added to it (t<t*<t+dt). At a sufficiently small time step dt, one can assume that t* = t.

I suggest that you only implement the second type of integral as the first can be done in post-processing of the OpenCOR output variables.

Regards, Peter


On 22/02/2017 8:50 AM, Mike Cooling wrote:

Dear Peter,

Happily, we believe that we can add support for integrals relatively easily, via the inclusion of some relevant mathml tags.

Even better, if you would like to send us some example equations that you want support for in CellML 2.0, we could ensure that we really are properly supporting the expression of the desired mathematics.

Best Regards,
Mike



On Mon, Feb 20, 2017 at 8:29 PM, Peter Hunter <p.hunter AT auckland.ac.nz <mailto:p.hunter AT auckland.ac.nz>> wrote:

Dear Mike et al,

I am finding that the lack of definite integrals is a considerable
limitation for the post-processing of solutions from CellML models. A
number of the models we are currently developing (based on bond graph
concepts) use power (the product of potential and flow) as a unifying
physical entity across different types of physical system. It is then
very useful to compute the integral of power over a specified time
interval to calculate the energy expenditure.

Regards, Peter


On 9/02/2017 10:51 AM, Mike Cooling wrote:
> Dear CellML Community,
>
> The '2.0 Specification Writing Group' is proud to present a draft
> specification for CellML 2.0.
>
> Unlike the CellML 1.x specifications, the CellML 2.0
specification is
> written in a formal, "normative" style. It consists largely of a
list
> of interlocking rules. This makes it difficult to meaningfully
'skim'
> the document, so for your convenience we present a Release Note
> highlighting the differences between CellML 1.1 and CellML 2.0. We
> recommend starting with that Note which can be found here:
>
> https://drive.google.com/open?id=0B7o2fHkRhadEeG10cDlIZkNsQk0
<https://drive.google.com/open?id=0B7o2fHkRhadEeG10cDlIZkNsQk0>
>
> The specification itself can be found here:
>
> https://drive.google.com/open?id=0B7o2fHkRhadEUnp4Zkx4ZTRkZXc
<https://drive.google.com/open?id=0B7o2fHkRhadEUnp4Zkx4ZTRkZXc>
>
> We invite community feedback on this draft specification. We are
also
> seeking more information, specifically, on the usefulness of the
> ability to include definite integrals in the mathematics (currently
> not in CellML 2.0). If you can provide details of models that need
> that feature, or wish to provide any other feedback on the
> Specification, please do so via this mailing list, or, if you
prefer,
> directly to my email address.
>
> Best Regards,
> Mike Cooling, on behalf of the CellML 2.0 Specification Writing
Group.

Attachment: Definite integral.docx
Description: application/vnd.openxmlformats-officedocument.wordprocessingml.document

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• [cellml-discussion] CellML 2.0 Draft Specification, Mike Cooling, 02/09/2017
  • Re: [cellml-discussion] CellML 2.0 Draft Specification, Lucian Smith, 02/11/2017
  • Message not available
    • Re: [cellml-discussion] CellML 2.0 Draft Specification, Mike Cooling, 02/11/2017
  • Re: [cellml-discussion] CellML 2.0 Draft Specification, Peter Hunter, 02/20/2017
  • Message not available
    • Re: [cellml-discussion] CellML 2.0 Draft Specification, Mike Cooling, 02/22/2017
      • Re: [cellml-discussion] CellML 2.0 Draft Specification, Peter Hunter, 02/22/2017

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