Version:

Last Modified: January 9, 2017

Performs two-dimensional interpolation using a selected interpolation method based on the lookup table defined by arrays of values of dependent and independent variables.

Interpolation method.

Name | Value | Description |
---|---|---|

nearest | 0 | Selects the |

bilinear | 1 | Sets the interpolated values to points along the line segments that connect |

bicubic | 2 | Yields an interpolated point from a bicubic surface that covers sixteen of the closest |

bicubic spline | 3 | Guarantees that the first and second partial derivatives of the cubic interpolating polynomials are continuous, even at the data points. |

The Nearest Method

The Bilinear Method

The bilinear method calculates the 1D linear interpolation twice along the x-axis and returns the interpolated values at points *a* and *b*, represented by the blue dots in the following illustration. This node then calculates the 1D linear interpolation along the y-axis, represented by the line segment that connects *a* and *b* in the following illustration, and returns **zi**_{m, n}.

The Bicubic Method

Use the bicubic method to perform interpolation within grid rectangles. This method ensures that the inside interpolated surfaces, their first partial derivatives, and the second-order mixed derivative all are continuous.

The Bicubic Spline Method

This method performs interpolation along one axis using the cubic spline method and then along the other axis using the same method. The bicubic spline method ensures that the first and second partial derivatives of the interpolation polynomials are continuous.

**Default: **bilinear

2D array of tabulated values of the dependent variable.

2D array of tabulated values of the first independent variable.

All interpolation methods require that **X** be monotonic along each row, and all rows must be identical. Otherwise, this node uses only the first row of **X** to perform the interpolation. If **X** is not empty, the number of columns in **X** must equal the number of columns in **Z**. If **X** is empty, this node treats **X** as an array whose size equals the size of **Z** and whose rows are [0, 1, …, *N* - 1], where *N* is the number of columns in **Z**.

2D array of tabulated values of the second independent variable.

All interpolation methods require that **Y** be monotonic along each column, and all columns must be identical. Otherwise, this node uses only the first column of **Y** to perform the interpolation. If **Y** is not empty, the number of rows in **Y** must equal the number of rows in **Z**. If **Y** is empty, this node treats **Y** as an array whose size equals the size of **Z** and whose columns are [0, 1, …, *M* - 1]^{T} , where *M* is the number of rows in **Z**.

Locations of the interpolation points.

Interpolations between each **X** element and each **Y** element are repeated **ntimes**. If you wire data to **xi** or **yi**, this node ignores **ntimes**.

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

**Default: **No error

2D array of values of the first independent variable at which interpolated values of the dependent variable are to be computed.

2D array of values of the second independent variable at which interpolated values of the dependent variable are to be computed.

The size of **yi** must equal the size of **xi**.

Is the output 2D array of interpolated values that correspond to the independent variable values.

2D array of values of the first independent variable at which interpolated values of the dependent variable are computed.

If you wire data to **xi**, **xi used** returns **xi** unchanged. Otherwise, **xi used** returns an array with identical rows of 2^{ntimes} - 1 points located evenly between each two adjacent elements in the first row of **X**, and the number of rows in **xi used** equals the number of rows in **yi used**.

2D array of values of the second independent variable at which interpolated values of the dependent variable are computed. If you wire data to **yi**, **yi used** returns **yi** unchanged. Otherwise, **yi used** returns an array with identical columns of 2^{ntimes} - 1 points located evenly between each two adjacent elements in the first column of **Y**, and the number of columns in **yi used** equals the number of columns in **xi used**.

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: Not supported