Lookup Table
Math1-D lookup table with linear interpolation. Maps input values to output values using a set of breakpoints and corresponding table data.
Mathematical Model
Given breakpoints x₀ < x₁ < ... < xₙ and table values y₀, y₁, ..., yₙ:
Extrapolation:
- clip: output = y₀ if x < x₀, yₙ if x > xₙ
- linear: extend interpolation slope from nearest interval
Inputs & Outputs
| Direction | ID | Label | Type | Status |
|---|---|---|---|---|
| → In | in |
In | number | Required |
| ← Out | out |
Out | number | Output |
Parameters
| Parameters | Label | Type | Default | Description |
|---|---|---|---|---|
breakpoints |
Breakpoints | text | 0 1 2 3 |
|
tableData |
Table Data | hidden | 0 1 4 9 |
|
interpolation |
Interpolation | select | linear |
|
extrapolation |
Extrapolation | select | clip |
Usage Examples
With breakpoints 0 1 2 3 and table data 0 1 4 9:
- Input 0.5 → Output 0.5 (interpolated between 0 and 1)
- Input 1.5 → Output 2.5 (interpolated between 1 and 4)
- Input 5.0 with clip → Output 9 (clamped to last value)
- Input 5.0 with linear → Output 19 (extrapolated)
Remarks & Best Practices
- Breakpoints monotonic: Breakpoints must be strictly increasing; non-monotonic breakpoints produce undefined results
- Table size: Table data length must exactly match the breakpoints length
- Extrapolation — clip: Safer for most applications; prevents output from exceeding the defined range
- Extrapolation — linear: Useful when the trend beyond the last breakpoint is known to continue linearly
- Performance: O(log n) lookup via binary search; efficient even with thousands of breakpoints
Related Components
- Constant: Eenvoudige signaalbron