Version:

Last Modified: December 12, 2016

Calculates a decimal y-value from an array of numbers or points at a specified fractional index or x-value using linear interpolation.

An array containing one of the two following data types:

- An array of numbers representing y values equally spaced along the x-axis.
- An array of points where each point is a cluster of x and y coordinates.

If this input is an array of points, the node uses the first element in the cluster (x) to obtain a fractional index by linear interpolation. The node then uses this fractional index to compute the output **y value** from the second cluster element (y).

The index or x-value at which the node should return a y-value. **fractional index or x** must be located directly on a point or between two points for the node to work correctly.

** fractional index or x** does not interpolate beyond the bounds of an array or data point set. For example, if the parameter is set lower than the first element or x-value in an array, the node returns the value of the first element or the y-value of the first data point. Similarly, if the parameter is set higher than the last element or x-value in the array, the node returns the value in the final element or the final y-value.

The interpolated value of the element at the fractional index or the interpolated y-value of the fractional data point in **array**.

If you wire an array of numeric values, Interpolate 1D Array interprets **fractional index or x** as a reference to the array elements.

If you wire an array of data point sets, Interpolate 1D Array interprets **fractional index or x** as a reference to the x-value elements within each data point set.

array | fractional index or x | y value | comments |
---|---|---|---|

[5, 7] | 0.5 | 6.0 | The output is halfway between the values at elements 0 and 1. |

Array of points [(3,7), (5,9)] |
3.5 | 7.5 | The output is the linearly interpolated value at the x-value corresponding to 3.5. |

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: DAQExpress does not support FPGA devices