Interpolates points in a 1D array that represents a 2D non-descending graph. This node compares a threshold to the values in an array, starting at a specified index, until it finds a pair of consecutive elements such that the threshold is greater than the value of the first element and less than or equal to the value of the second element.  ## array of numbers or points

An array of numbers or an array of points where each point is a cluster of x- and y-coordinates.

If this input is an array of numbers, this node assumes the x-coordinates are the same as the indexes of the array itself.

If this input is an array of points, this node uses the second elements in the clusters, or the y-coordinates, to obtain a fractional index that it then uses to interpolate the corresponding x value. ## threshold y

The threshold value for the node. If threshold y is less than or equal to the array value at start index, the node returns start index for fractional index or x. If threshold y is greater than every value in the array, the node returns the index of the last value. If the array is empty, the node returns NaN. ## start index

The index to start interpolation.

Default: 0—The node returns the result calculated from the entire array rather than a specified section of the array. ## fractional index or x

The interpolated result calculated for the array of numbers or points 1D input array.

If array of numbers or points is an array of points where each point is a cluster of x- and y-coordinates, fractional index or x is the interpolated x value corresponding to the interpolated position of threshold y among the y-coordinates, rather than the fractional index of the array. fractional index or x returns the interpolated x value associated with the given y value if you graphed the points.