| T O P I C R E V I E W |
| jd0331 |
Posted - 02/17/2010 : 3:58:57 PM
Origin Ver. and Service Release (Select Help-->About Origin): 8
Operating System: xp
Hello,
I have two questions.
1) I would like to plot histograms on the logarithmic scale with the same spacing. When I tried it, the spacing between each column was not consistent due to the scale-See attachment. Would you let me know how to do it? Please note that I want to plot the bins on the log scale(x-axis).
2) I want to Fit the multiple peaks with Gaussian Distribution function on the logarithmic x-scale as shown in the enclosed file. Only two peaks are fitted by the researchers, but I hope to fit more than two peaks--three or four. Is it possible? If so, please let me know.
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| 3 L A T E S T R E P L I E S (Newest First) |
| Sam Fang |
Posted - 09/19/2011 : 04:41:32 AM
Here is the solution from Larry.
You can convert your x to log(x) before fitting. Then fit the curve by Gauss function, and generate xc value on linear space by Derived Parameters. You can follow below steps:
1.
In the worksheet, col(c) = log(col(a)) and set as X, col(d) = col(b). Then fit column c & d by Gauss function. To show the POSITION values for peak1 and peak2 i.e. xc values in raw data space, Derived Parameters can be used.
2.
Before fitting the curve, we need to define the derived parameter. Press F9 to open Fitting Function Organizer. Look for Gauss function, and add one command in Derived Parameter edit box,
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xc_linear = 10^xc
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3.
Create two plots Graph1 (column A, B) and Graph2 (column C, D), and set x axis in Graph1 as Log10 scale. Merge these two graphs (Graph : Merge Graph Windows), and link the axis, then you will have a new graph like Graph3. You can adjust the tick labels as you need.
4.
Fit the data. With Graph3 active, select the proper layer that include column C & D. Then bring up Nonlinear Fitting dialog and select Gauss function. Set the replica to 1 and fit.
In the result table, you can see there is one more variable, xc_linear, show the peak center value in raw data space.
Sam
OriginLab Technical Services |
| domnacz |
Posted - 09/14/2011 : 5:19:17 PM
So what's the solution to this problem? I'm having the exact same issue. |
| easwar |
Posted - 02/18/2010 : 11:19:33 AM
Hi,
I have e-mailed you asking for your data.
Thanks,
Easwar
OriginLab |
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