2.2.25 reducexy
Menu Information
Analysis: Data Manipulation: Reduce by Group
Brief Information
Reduce XY data using subgroup stats on X
Additional Information
Minimum Origin Version Required: 8.1 SR0
More options are introduced since 2015 SR0
Command Line Usage
1. reducexy iy:=(col(A),col(B)) subgroup:=inc xincr:=0.5 xstats:=median ystats:=min;
2. reducexy iy:=(col(A),col(B)) subgroup:=points points:=8 xstats:=ave ystats:=ave;
Variables
Display Name

Variable Name

I/O and Type

Default Value

Description

Input

iy

Input
XYRange

<active>

Specifies the input data range.

SubGroup Method

subgroup

Input
int

0

Specifies the method to divide the source data into subgroups. Then data points in each group will be merged into a single data point.
Option list:
 points:By Every N Points
 Every N points in the source data is grouped into a subgroup. You can specify the value of N with the points variable.
 groups:By Number of Groups
 You specify a number m with the groups variable. Then the source data is divided into m groups.
 inc:By X Increment
 You specify an increment with the xincr variable. Then the X range of the source data is divided into subranges according to the increment. Data points in each subrange is grouped into a subgroup.

N

points

Input
int

<auto>

This is only available when By Every N Points is selected in SubGroup Method. It specifies a number n. Then every n data points in the input range are merged into one data point.

X Increment

xincr

Input
double

<auto>

This is only available when By X Increment is selected in SubGroup Method. It specifies a value dx. Then the input data points are divided into several groups using dx so that for any two data points which belong to the same group, the difference in their X values cannot exceed dx. After grouping, each group of data points will be merged into one. When xincr is not specified, its default value is automatically calculated by the this equation: xincr = endstart / nsize * 5, where nsize is the number of input data points.

Groups

groups

Input
int

<auto>

This is only available when By Number of Groups is selected in SubGroup Method. It specifies the number of groups.

X Start

start

Input
double

<auto>

Specifies the X value to start grouping.

X End

end

Input
double

<auto>

Specifies the X value to end grouping.

Merged X by

xstats

Input
int

0

Specifies the way to pick the X value of the output data point, into which a group of data points are merged.
Option list:
 ave:Average
 The average of the X values of the data points in each group.
 median:Median
 The median of the X values of the data points in each group.
 first:First in Subgroup
 The X values of the first data point in each group.
 last:Last in Subgroup
 The X values of the last data point in each group.
The next three items are available when SubGroup Method is By X Increment or By Number of Groups.
 begin:Subgroup Beginning
 The beginning value in each subgroup.
 center:Subgroup Center
 The center value in each subgroup.
 end:Subgroup End
 The end value in each group.

Merged Y by

ystats

Input
int

0

Specifies the way to pick the Y value of the output data point, into which a group of data points are merged.
Option list:
 ave:Average
 The average of the Y values of the data points in each group.
 min:Min
 The minimum of the Y values of the data points in each group.
 The maximum of the Y values of the data points in each group.
 median:Median
 The median of the Y values of the data points in each group.
 first:First in Subgroup
 The Y values of the first data point in each group.
 last:Last in Subgroup
 The Y values of the last data point in each group.
 sum:Sum
 The sum of the Y values of the data points in each group.
 sd:SD
 The standard deviation of the Y values of the data points in each group.
 se:SE
 The standard error of the Y values of the data points in each group.
 rms:RMS
 The RootMeanSquare of the Y values of the data points in each group.

Output

oy

Output
XYRange

<new>

Specifies the output range.
See the syntax here.

Description
This Xfunction allows you to reduce XY data based on X values. The X values are required to be monotonic.
It provides multiple methods to group the data. After being grouped, each group of data points are merged into a single data point. You can specify the way to pick the X and Y values of the output data point.
Example
There is a dataset whose X values are not evenly spaced, and you want to reduce the data according to the X values. The dataset contains 200 data points. If you perform the following steps, you will get 50 of them:
 Start with a new book and click Import Single ASCII button and import file \Samples\Signal Processing\Convolution.dat.
 Highlight the data columns and then select Plot: Symbol: Scatter from the Origin menu to create a graph.
 Select Analysis: Data Manipulation: Reduce by Group from the main menu to open the dialog box of the reduceXY XFunction.
 In the dialog box, select By Number of Groups with the SubGroup Method dropdown list. Then uncheck Auto checkbox to the right of Groups and enter 50 in the edit box.
 Select First in Subgroup with the Merged X by dropdown list.
 Select Min with the Merged Y by dropdown list.
 Click the OK button. The results are saved in the input worksheet next to the raw data. Highlight X2 and Y2 columns and then select Plot: Symbol: Scatter from the Origin menu to create a graph.
You can also use the following script command to reduce the data points:
reducexy r 2 iy:=[Book2]Convolution!(col(A),col(B)) subgroup:=groups groups:=50 xstats:=first ystats:=min;
Related XFunctions
stats, reducedup, xy_resample
Keywords:data reduction, average, mean, sum, minimum, maximum, statistics
