2.8.12 interp1trace

Menu Information

Analysis: Mathematics: Trace Interpolation

Brief Information

Perform trace/periodic interpolation of XY data

Command Line Usage

1. interp1trace iy:=Col(2) method:=spline npts:=50;

2. interp1trace iy:=Col(2) method:=bspline;

X-Function Execution Options

Please refer to the page for additional option switches when accessing the x-function from script

Variables

Display Name	Variable Name	I/O and Type	Default Value	Description
Input	iy	Input XYRange	<active>	The XY range to be interpolated.
Method	method	Input int	linear	Specifies the interpolation method. Option list linear:Linear Use linear interpolation method. Cubic spline Use cubic spline interpolation method. Cubic B-spline Use cubic B-spline interpolation method.
Number of Points	npts	Input int	<auto>	Specifies the number of interpolated points. If npts is not specified, default <auto> = min( n*5, 1000), where n is the number of input points. i.e. if number of points n is less than 200, npts=5*n, otherwise npts=1000.
Output	oy	Output XYRange	<new>	The XY range of interpolation result. See the syntax here.

Description

When a curve is cyclic, or periodic, it is improper to use ordinary interpolation because the algorithm interpolates the curve based on adjacent data points in the X coordinate. This causes the cycle trend to be lost.

This function interpolates a curve and keeps the trend.

Examples

1. Import the file \Samples\Mathematics\ Circle.dat.

2. Highlight the data and plot a scatter.

3. Select Analysis: Mathematics: Trace Interpolation from menu to bring up the dialog.

4. Select Cubic B-spline interpolating method, and enter 50 on the Number of Points edit box.

5. Click OK to execute.

Algorithm

Detail algorithms please refer to the help of interp1.

Related X-Functions

interp1, interp1q, spline, bspline, interp1xy, interpxyz

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Keywords:interpolate, extrapolate