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Numerical derivative
Posted 2010/12/01 16:29 GMT-5 3 Replies
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Hi,
I am using a scalar variable f(T) in a transient heat transfer model. Since the model is transient, T is dependent on time. How can I calculate the derivative df/dt (numerically or analytically)?
I need to know the derivative df/dt, since I want to specify another function g(df/dt).
Thanks in advance
Ivan
I am using a scalar variable f(T) in a transient heat transfer model. Since the model is transient, T is dependent on time. How can I calculate the derivative df/dt (numerically or analytically)?
I need to know the derivative df/dt, since I want to specify another function g(df/dt).
Thanks in advance
Ivan
3 Replies Last Post 2010/12/03 1:26 GMT-5
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Posted:
1 decade ago
Hi
in 4.1 check the doc about the "prev()" operator. Do an indexed search on the pdf doc.
I notice that 90% of the replies on the forum can be solved by a quick search on the pdf doc.
I find too that the doc are dense and one need to read them several times, but in fact about everything is in there (for 3.5a =< doc >= 4.1 ;)
--
Good luck
Ivar
in 4.1 check the doc about the "prev()" operator. Do an indexed search on the pdf doc.
I notice that 90% of the replies on the forum can be solved by a quick search on the pdf doc.
I find too that the doc are dense and one need to read them several times, but in fact about everything is in there (for 3.5a =< doc >= 4.1 ;)
--
Good luck
Ivar
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Posted:
1 decade ago
Hi,
I am currently using v3.5, there the prev() command is not available. I tried the diff() command, but that one holds only if there is an explicit dependence on time.
Best
Ivan
I am currently using v3.5, there the prev() command is not available. I tried the diff() command, but that one holds only if there is an explicit dependence on time.
Best
Ivan
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Posted:
1 decade ago
Hi
indeed v4 has among many other improvements the prev() operator.
I have decided currently to use the v4.1 for "serious/client" work, and have decided to forget 3.5a. The main issue I still have is the lack of a "summary report", but by doing a file reset and save the model as a ".m" file I have a readable trace (for me), apart that my clients are not able to understand it ;)
--
Good luck
Ivar
indeed v4 has among many other improvements the prev() operator.
I have decided currently to use the v4.1 for "serious/client" work, and have decided to forget 3.5a. The main issue I still have is the lack of a "summary report", but by doing a file reset and save the model as a ".m" file I have a readable trace (for me), apart that my clients are not able to understand it ;)
--
Good luck
Ivar