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1-Newbie

## Multiple input values to a differential solve block

It would appear logical that one should be able to turn the output variable of a solve block such as attached into a function which can then invoke the solve block numerous times in order to solve a differential equation and generate multiple output functions. In other words, a series of input variables which are defined before entering the solve block can be called upon to solve the differential equation multiple time. Can someone explain to me how this can be done using the attached example.

Mark Buckton

3 REPLIES 3
19-Tanzanite
(To:MBuck2)

You have to remember that Odesolve returns a function, and therefore psteeltemp is a function that returns a function (not a value)

See the attached.

17-Peridot
(To:RichardJ)

Here's a slightly different approach from Richard's that might help.

Alan

1-Newbie
(To:MBuck2)
 Mark Buckton wrote:It would appear logical that one should be able to turn the output variable of a solve block such as attached into a function which can then invoke the solve block numerous times in order to solve a differential equation and generate multiple output functions. In other words, a series of input variables which are defined before entering the solve block can be called upon to solve the differential equation multiple time. Can someone explain to me how this can be done using the attached example.Thanking you in advanceMark Buckton

You must disambiguate your mind about Odesove and the likes. Odesolve is numerical, not functional. What that means is that the solution(s) is/are calculated at the number of points you have specified. In the case of the Mathcad 11 and earlier version, this vector of solution is resident at the solver level. When you plot sol(t), this call does the lspline over the internal data of the Odesolve. What that means is that no Mathcad numerical solve block will output a function, only a fit to the data representing the numerically found solution. The process of trying to get a function as the solution to the Odesove is called "collocation". This is easy to do outside of the odesolve block by applying the best fitting model, which them "best fitting model" requires some fitting expertise ... consequently excluding a single "collocation algorithm". Several Mathcad 11 work sheets were done and reposted "collocated" c/w a "best fit model" function, so that the collab could parametrize the unique Odesolve of his project and get an export of the solution as "collocated".

If it looks jargon to you, it is not. You may need to decipher the DE numerical solvers.

jmG

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