2.8.13 interp1xy

1 Menu Information
2 Brief Information
3 Command Line Usage
4 X-Function Execution Options
5 Variables
6 Examples
7 More Information
8 Related X-Functions

Menu Information

Analysis: Mathematics: Interpolate/Extrapolate

Brief Information

Perform interpolation/extrapolation of XY data with multiple methods

Command Line Usage

1. interp1xy iy:=Col(2) method:=spline npts:=50;

2. interp1xy iy:=Col(2) method:=bspline sf:=0.5;

3. interp1xy iy:=Col(2) method:=bspline npts:=50 coef:=Col(3);

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>	Specifies the XY range to be interpolated.
Method	method	Input int	0	Interpolation methods Option list: linear:Linear method:=0, Linear interpolation is a fast method of estimating a data point by constructing a line between two neighboring data points. The resulting point may not be an accurate estimation of the missing data. spline:Cubic Spline method:=1, This method splits the input data into a given number of pieces, and fits each segment with a cubic polynomial. The second derivative of each cubic function is set equal to zero. With these boundary conditions met, an entire function can be constructed in a piece-wise manner. bspline:Cubic B-Spline method:=2, This method also splits the input data into pieces, each segment is fitted with discrete Bezier splines. akima:Akima Spline method:=3, This method is based on a piecewise function composed of a set of polynomials. The akima interpolation is stable to outliers. You could refer to the algorithm of each interpolation methods.
Generate X Data by	xby	Input int	0	It supplies two options for generating X Data. Option list: 0=npts: Number of Points Specifies the number of interpolated points. 1=inc: Increment Specifies the increment when interpolate by Sampling Interval
X Increment	inc	Input double	0	This is available only when Generate X Data by is Increment. Specifies the x increment when interpolate by Sampling Interval
Number of Points	npts	Input int	<auto>	This is available only when Generate X Data by is Number of Points. Specifies the number of interpolated points. If npts is not specified, default <auto> = min( n5, 1000), where n is the number of input points. i.e. if number of points n is less than 200, npts=5n, otherwise npts=1000.
X Start	xmin	Input double	<auto>	The minimum X value of interpolated curve
X End	xmax	Input double	<auto>	The maximum X value of interpolated curve
Boundary	boundary	Input int	1	Boundary condition only available in cubic spline method Option list: natural:Natural 2nd derivatives are 0 on both end notaknot:Not-A-Knot 3rd derivatives are continuous on the second and last-second point
Smoothing Factor	sf	Input double	<auto>	A non-negative parameter that specifies the smoothness of the interpolated curve in Cubic B-Spline interpolation. The factor helps user control the balance between the smoothing and closeness. Larger values will result in smoother curves.
Apparent Interpolation	apparent	Input int	0	It is available only when the interpolation is performed on a graph. It specifies whether to use the apparent values for interpolation if the types of the axes scales have been changed to other types.
Output	oy	Output XYRange	(<autoX>,<new>)	Specifies the output XY data range See the syntax here.
Coefficients	coef	Output vector	<optional>	Show the coefficients or not, and show them in which column.