Interpolation

These category functions provide calculation of the interpolated value.

Name Generated Expression Description Expression Example Ex

line

line(  , x1, y1, x2, y2,…)

Interpolated value using linear interpolation.

line($Ahd$, 0, 0, 0, 1000)

17

splineN

splineN(  , x1, y1, x2, y2,…)

Interpolated value using cubic spline interpolation (derivative in node points are equal to zero).

splineN($Ahd$, 0, 1000, 500, 0, 1000, 1000)

 

spline

spline(  , x1, y1, x2, y2,…)

Interpolated value using cubic spline interpolation.

spline($Ahd$, 0, 0, 0, 1000)

line2D

line2D( , , numX, numY, x1,…, y1,…., z1,…)

Interpolated value using linear interpolation (2D case).

line2D($X$, $Y$,  2, 2, 0, 1, 0, 1, 10, 20, 20, 40)

splineN2D

splineN2D( , , numX, numY, x1,…, y1,…, z1,…)

Interpolated value using cubic spline interpolation (derivative in node points are equal to zero, 2D case).

splineN2D ($X$, $Y$,  2, 2, 0, 1, 0, 1, 10, 20, 20, 40)

spline2D

spline2D( , , numX, numY, x1,…, y1,…, z1,…)

Interpolated value using cubic spline interpolation (2D case).

spline2D($X$, $Y$,  2, 2, 0, 1, 0, 1, 10, 20, 20, 40)

Result is calculated for x (or x, y) argument. Parameters x1, y1, x2, y2, ...(or numX, numY, x1, …, y1,…, z1, …) are known function points (argument, value).

Example 17 Interpolation, 1D interpolation

From left to right:
line( $Ahd$, 0, 50, 700, 150, 1200, 120, 2000, 10, 2600, 100)
spline( $Ahd$, 0, 50, 700, 150, 1200, 120, 2000, 10, 2600, 100)
splineN( $Ahd$, 0, 50, 700, 150, 1200, 120, 2000, 10, 2600, 100)    click to enlarge