DADiSP Worksheet Functions > Function Categories > Curve Fitting > INTERPOLATE

 

INTERPOLATE

Purpose:

Linearly interpolates N points between existing points.

Syntax:

INTERPOLATE(series, n)

series

-

A series or table, the data to linearly interpolate.

n

-

An integer. The interpolation factor.

Returns:

A series or table, the linearly interpolated result.

Example:

W1: {1, 2, 3}

W2: interpolate(W1, 2)

 

W2 contains the series {1, 1.5, 2, 2.5, 3}

Example:

interp(W1, 5)

 

increases the size of the series from Window 1 by a factor of 5 and places the result in the current Window. This new series is created by inserting five points between each point of W1 by linear interpolation.

Example:

interp(extract(W2, 10, length(W2)-10), 4)

 

increases the size of the series from Window 2 by a factor of 4, starting from the 10th point of the series, and places the result in the current Window.

Remarks:

INTERPOLATE automatically adjusts the sample rate (1/DELTAX) of the resulting series.

 

INTERPOLATE can be abbreviated INTERP.

 

See SPLINE for cubic spline interpolation.

 

See RESAMPLE to resample a series to an arbitrary rate.

 

See XYINTERP to linearly interpolate XY data (a series with arbitrary X values) into an interval series (constant deltax).

 

See XYLOOKUP to find a Y value from an arbitrary X value with possible interpolation.

 

See OUTLIER to replace outlier values with a linear interpolation of the surrounding values.

See Also:

DECILP

DECIMATE

DELTAX

INTERP2

OUTLIER

POLYFIT

RATE

RESAMPLE

SPLINE

UPSAMPLE

XYINTERP

XYLOOKUP