| T O P I C R E V I E W |
| waynie |
Posted - 03/12/2014 : 10:49:56 AM
Hello,
When fitting multiple curves to an equation on the same graph (each curve has its own x axis), the fitted curves rescales itself to the x-axis of the 1st fit performed. This messes up the graph.
Before performing a fit, when selecting the data set, instead of selecting just the y axis data, how do I select both the X and Y data for each curve?
Thanks!
Waynie Schuette |
| 2 L A T E S T R E P L I E S (Newest First) |
| greg |
Posted - 03/14/2014 : 12:29:26 PM
You don't mention which fitter you are using in Origin 7, so I will assume you are using the Advanced fitter since the Wizard correctly associates a Y with its X.
In the Advanced fitter, under Action : Dataset (or Select Dataset in Basic view) you:
Select the y Dep item in Variables
Select which Available data is the y dataset
Click Assign
Select the ---->x Indep item in Variables
Select which Available data is the x dataset
Click Assign
I think Origin 7 often did not auto-assign the correct x for more than one dataset in a layer so subsequent datasets require the X Assign.
You cannot constrain a fit through a point. You can use error bars to force a fit through a point. Set your error bar values to 1 except at the point in question where you can use a small, non-zero value (1E-3). Be sure to plot the error bars. |
| waynie |
Posted - 03/12/2014 : 12:42:05 PM
Also, how do you type out a constraint so that the fit will go through the first data point on the data set?
Waynie Schuette |
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