| Author |
 Topic  |
|
|
alextrv
3 Posts |
|
|
Shirley_GZ
China
Posts |
 Posted - 06/27/2016 : 06:13:15 AM
|
Hi,
Actually, Origin supports to define such an ordinary differential equation directly and perform a fit of the data using this fitting function. See details in this tutorial:
http://www.originlab.com/doc/Tutorials/Fitting-Ordinary-Differential-Equation
Of course, you are also allowed to define the function in the numeric model just as the reference shows. But more details are needed here:
1) If the equation of the fitting function is as below?
Y=LA + RI1*$1 + RI2*$2 + RI3*$3 + RI4*$4 + RI5*$5 + Drift*(t-ton1))
Y is the Dependent variable, t is the independent variable and others are the intermediate variables(such as $1 and $2) and parameters(such as RI1 and ton1), right?
2) What do the equations below mean? (I mean the separator "|")
A=$6–$7|0;
L=-$7|Rmax;
LA=$7|0;
3) In "Parameter setup" table, I see some parameters are labeled as No in column "Keywaord", others are labeled as Yes. Is "Keyword" used to mark the Constants(which will be fixed during fitting)? If so, the fixed value should be provided.
More explanations about the function are appreciated.
Additionally, could you send us the .fdf files you had created(via tech@originlab.com) to let me do further checking? Please also provide the serial number of your Origin when you contact with us with emails. Thanks.
Best Wishes,
Shirley
Originlab Technical Service Team |
 |
|
|
dr.m.umer
Canada
1 Posts |
Posted - 04/14/2023 : 2:51:36 PM
|
Hi Shirley
I am trying to build function using the same numeric model.
I am facing two error notices. Firstly, the origin tells me $1,$2...$7 are invalid derived variables
Once I change these values to arbitrary letter symbols (e.g., e, f, etc. not found elsewhere in the equation, at the "derived parameter equations" tab, when I input the equations for all derived parameters, I receive the following error message "derived parameters cannot be used to derive other derived parameters"
What could I be doing wrong?
And the the separator "|" means initial value of the corresponding variable or parameter. For example, $7|0 indicates that the initial value of $7 is 0. |
|
|
|
ralcala
USA
1 Posts |
Posted - 01/23/2024 : 2:08:13 PM
|
Hi dr.m.umer
I was wondering if you had any success with this equation? I have been trying to build this same equation into Origin without much luck (and this is the only source of the equation I have found as well!. Any help is appreciated.
Rafael |
|
|
| |
Topic |
|
|
|
Personal fit function