reducedup

1 Menu Information
2 Brief Information
3 Additional Information
4 Command Line Usage
5 Variables
6 Description
7 Example
8 Algorithm
9 Related X-Functions

Menu Information

Reduce Duplicate X Data

Brief Information

Reduce data to consolidate XY pairs with same X values

Additional Information

Minimum Origin Version Required: 8.1 SR0

Command Line Usage

reducedup method:=mean tol:=1 xcount:=<new>

Variables

Display Name	Variable Name	I/O and Type	Default Value	Description
Input	iy	Input XYRange	<active>	Specifies the input data range.
Replace Y With	method	Input int	0	Specifies the value that is used to replace the Y values that correspond to equal X values. Option list: mean:Mean Replaces the data points in each group with the mean value of these data points. median:Median Replaces the data points in each group with the median value of these data points. min:Min Replaces the data points in each group with the minimum value of these data points. max:Max Replaces the data points in each group with the maximum value of these data points. sum:Sum Replaces the data points in each group with the sum of these data points.
Tolerance	tol	Input double	1.0e-8	Specifies the tolerance used to test whether two X values are equal. For more details, please refer to the Algorithm section below.
Output	oy	Output XYRange	<new>	Specifies the output range. See the syntax of Output Notations.
Duplicate X Counts	xcount	Output XYRange	<new>	Specifies whether or not to output the count of duplicate X. See the syntax of Output Notations.

Description

This X-Function is for removing data rows that have duplicated X values. After reducing the input data with this X-Function, there will not be any pair of X values that are equal to each other. The Y values that correspond to equal X values in the original data will be replaced with a chosen statistical quantity.

Example

The following example shows you how to reduce several rows of data that contain duplicate X values.

Create a workbook and import the data <Origin Program Folder>\Samples\Mathematics\Circle.dat.
Highlight the columns in the worksheet and select Plot: Line: Line from the main menu to create a graph.
Make the graph active. Select Analysis: Data Manipulation: Reduce Duplicate X Data from the Origin menu to open the dialog box of the reducedup X-Function.
Check Auto Preview so that we can see the current result in the Preview window when we change the dialog options.
Choose Min with the Replace Y With drop-down list.
Check Duplicate X Counts and enter [<new>]<new> after it. This ensures that you will get the counts of duplicate Xs after reducing the data.
Click the OK button. You can see the results in the original workbook and the graph.
Now we plot the reduced data separately. Go to the workbook. Highlight col(C) and col(D). Select Plot: Line: Line from the Origin menu to create a new graph.

Algorithm

Tolerance for testing whether two values are equal

Some X-Functions that test for equality include a tolerance. This algorithm tests whether two X values are equal.

For a given vector, firstly sort it ascending, and suppose the sorted vector is $\left (x_1, x_2, x_3, ..., x_n \right )$ , where $n$ is the size of the vector. The following steps are the procedure for testing whether two X values are equal with a specified tolerance, $t o l$ .

Find the maximum and minimum of the vector, say $m a x$ and $m i n$ respectively.
Calculate a testing value, $d T o l$ , by using:
$dTol = tol * \left ( max - min \right )$
Loop over all values in the sorted vector, from $x 1$ to $x n$ , comparing the absolute value of $\left ( x_n - x_{n-1} \right)$ with $d T o l$ .
If $abs \left ( x_n - x_{n-1} \right ) \le dTol$ , we will say that $x_n = x_{n-1} \,$ , else, $x_n \ne x_{x-1}$ .
When multiple X values are determind equal, say $\left ( x_i, x_{i+1}, ..., x_j \right )$ , where $1 \le i < j \le n$ , the display X value for this "equal" X values is defined as:
If the number of this "equal" X values is even, the display X value is $x_{\frac {i + j - 1}{2}}$ .
If the number of this "equal" X values is odd, the display X value is $x_{\frac {i + j}{2}}$ .

Related X-Functions

stats, reducexy