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Offline Razonar  
#1 Posted : 30 November 2018 01:09:04(UTC)
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Hi. I can't reproduce this in SMath.

Clipboard01.gif

Integrate with ode solver.sm (7kb) downloaded 6 time(s). Integrate with ode solver.zip (9kb) downloaded 2 time(s).

Best regards.
Alvaro.
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Offline Jean Giraud  
#2 Posted : 30 November 2018 05:48:00(UTC)
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Originally Posted by: Razonar Go to Quoted Post
I can't reproduce this in SMath.


1/1 in Smath 6179, proof: the snippet.

Cheers Alvaro

IntegrateODE.PNG

Integrate with ode solver.sm (30kb) downloaded 7 time(s).
Offline Jean Giraud  
#3 Posted : 30 November 2018 05:59:54(UTC)
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Originally Posted by: Razonar Go to Quoted Post
I can't reproduce this in SMath.

You may not be able to implement the Mathcad bloc Given/ODEsolve.
ODEsolve is based on linterp. That is the first point.
The other point is that in Mathcad "linterp(x)" is a scalar function.
In Smath: ainterp, cinterp, linterp are simply interpolation fncts
They are not scalar functions. How does it reflects in ODEsolve ?
In Smath, ln(x), exp(x), ... are scalar from source code.
I tried to make cinterp scalar like in Mathcad, not to avail.

Please, persist on such a beautiful idea.

Offline Jean Giraud  
#4 Posted : 30 November 2018 07:16:48(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
I tried to make cinterp scalar like in Mathcad, not to avail.

This document was essentially designed to plot scalar the derivative on canvas,
as well as get a discrete export. Also included: the scalar quadratic.

Cheers ... Jean

Spline Deriv Infinitesimal.sm (71kb) downloaded 7 time(s).


Offline Razonar  
#5 Posted : 30 November 2018 08:31:22(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post

You may not be able to implement the Mathcad bloc Given/ODEsolve.


Hi Jean. Actually not, just the solver, without the given.
I found how to call the odesolver, with D(x,y)=[f(x)].
This method is much more faster than the direct integration.
But remains the ln(0) error, which seems to be a bug in the odesolvers, because zero isn't in the domain range.

Clipboard01.gif

Integrate with ode solver.sm (11kb) downloaded 11 time(s).

Best regards.
Alvaro.

Edited by user 30 November 2018 08:33:22(UTC)  | Reason: Not specified

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Offline uni  
#6 Posted : 30 November 2018 09:35:52(UTC)
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The zero point is used to determine the dimension of the vector D(t,x) at runtime (D(0, x0)). The size of the system must be determined for the further operation of the numerical algorithm. It seems that it would be correct to substitute the beginning of the interval. I will try to change this. Also, if possible, I will support the one-dimensional case.
Russia forever!
Viacheslav N. Mezentsev
💰 You can support me for plugins development: https://paypal.me/viacheslavmezentsev
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Offline Razonar  
#7 Posted : 30 November 2018 11:01:06(UTC)
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Thanks Viacheslav. It's amazing the effort that you and the others plugins developers put in enhance SMath, with very spectacular results.
Best regards.
Alvaro.
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on 03/12/2018(UTC)
Offline Jean Giraud  
#8 Posted : 30 November 2018 18:29:42(UTC)
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Originally Posted by: Razonar Go to Quoted Post
Hi Jean. Actually not, just the solver, without the given.
I found how to call the odesolver, with D(x,y)=[f(x)].
This method is much more faster than the direct integration.
But remains the ln(0) error, which seems to be a bug in the odesolvers, because zero isn't in the domain range.


Buenos dias Alvaro !

ln(0) was introduced in Mathcad 11 soon after release via update [from recollection]
There is more in the attached, specially wrt parametric D(,,,).
Jean

ODEsolve.PNG

ODE 0_Model General.sm (30kb) downloaded 3 time(s).


Offline Jean Giraud  
#9 Posted : 30 November 2018 18:34:54(UTC)
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...

ODEsolve.PNG
Offline Jean Giraud  
#10 Posted : 30 November 2018 21:36:38(UTC)
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... refreshed version wrt explore all solvers.

ODE 0_Model General.sm (39kb) downloaded 13 time(s).
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