interp2 — Interpolate values over a two-dimensional gridded surface.

interp2(X, Y, Z, Xq, Yq) estimates surface values at query points from gridded data. Vector axes and meshgrid-style coordinate matrices are accepted. interp2(Z, Xq, Yq) uses implicit axes based on the rows and columns of Z.

Syntax

Zq = interp2(Z, Xq, Yq)
Zq = interp2(X, Y, Z, Xq, Yq)
Zq = interp2(X, Y, Z, Xq, Yq, method)

• Z is a dense 2-D matrix of sampled surface values.
• X and Y may be vector axes or meshgrid-style coordinate matrices matching Z. When omitted, implicit column and row axes are used.
• Xq and Yq are scalar or same-size query arrays. Scalar queries broadcast against array queries.
• method may be linear or nearest in the initial implementation. The default is linear.
• Out-of-range queries return NaN by default. Pass 'extrap' to extrapolate or pass a scalar fill value.

How interp2 works

• Supports linear and nearest methods in the initial implementation.
• Out-of-range query points return NaN unless an extrapolation value or 'extrap' is supplied.
• Dense real numeric inputs are supported. GPU inputs gather to the host reference path.

Examples

Bilinear interpolation with implicit axes

Z = [1 2; 3 4];
zq = interp2(Z, 1.5, 1.5)

Expected output:

zq = 2.5

Interpolation with meshgrid axes

[X, Y] = meshgrid([10 20], [100 200]);
Z = [1 2; 3 4];
zq = interp2(X, Y, Z, 15, 150)

Expected output:

zq = 2.5

Related Math functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how interp2 works, line by line, in Rust.

• View interp2.rs on GitHub
• Learn how the runtime works
• Found a bug? Open an issue with a minimal reproduction.

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