1-D Lookup Table
Approximate one-dimensional function.
Description
Block 1-D Lookup Table calculates the approximate value of some function:
,
where the function can be empirical.
Block icon 1-D Lookup Table displays the graph of the function defined in the block.
The block maps the input data to a table of output values using interpolation and extrapolation methods.
The block supports the following interpolation methods: Flat, Linear point-slope, Linear Lagrange, Nearest, Cubic spline и Akima spline.
You can read more about interpolation methods here: Methods of approximation of function values
Setting reference points and output value table
These block parameters set the values for the datums and the output table.
| Block parameter | Назначение |
|---|---|
Breakpoints 1 |
Sets the vector of reference points. |
Table data |
Defines the corresponding set of output values. |
How the block generates output data
Block 1-D Lookup Table generates output data by searching the table or by evaluating values based on input values.
| Block input data | Block behaviour 1-D Lookup Table |
|---|---|
Match the values in the datasets of the reference points |
Outputs tabular value |
Does not match the values in the datasets of the anchor points, but is within the range. |
Interpolates the corresponding table values using the selected value Interpolation method |
Do not match the values in the datasets of the reference points and are out of range |
Extrapolates the output value using the selected Extrapolation method |
Ports
Input
#
IN_1
—
input signal
scalar | vector | matrix
Details
An input signal , matched to an output value by searching or interpolating from a table of values.
| Data types |
|
| Complex numbers support |
Yes |
Output
#
OUT_1
—
output signal calculated by searching or evaluating table values
scalar | vector | matrix
Details
An output calculated by finding or evaluating table values based on input values.
| When the input data of a block is… | Then the block 1-D Lookup Table… |
|---|---|
Match the values in the datasets of the reference points |
Outputs a tabular value |
Do not match the values in the datasets of the anchor points, but are within range |
Interpolates the corresponding table values using the selected value. Interpolation method |
Do not match the values in the anchor point datasets and are out of range |
Extrapolates the output value using the selected Extrapolation method |
| Data types |
|
| Complex numbers support |
Yes |
Parameters
Основные
#
Table data —
output value table
Array of real and/or complex numbers
Details
Table of output values.
| Default value |
|
| Program usage name |
|
| Tunable |
Yes |
| Evaluatable |
Yes |
#
Breakpoints 1 —
reference point values for the first measurement
Array of real numbers
Details
Reference points for the first measurement.
| Default value |
|
| Program usage name |
|
| Tunable |
Yes |
| Evaluatable |
Yes |
Lookup method
#
Interpolation method —
method of interpolation between the values of reference points
Flat | Nearest | Linear point-slope | Linear Lagrange | Cubic spline | Akima spline
Details
When the input signal falls between the reference point values, the unit interpolates the output value using the neighbouring points.
Read more about interpolation methods here: Methods of approximation of function values
Dependencies
-
If you select `Cubic spline`then the block will only support scalar signals. Other interpolation methods support non-scalar signals.
-
If you select
Akima spline, the extrapolation method can only beAkima spline.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Extrapolation method —
a method of processing input values that are outside the range of the dataset of reference points
Clip | Linear | Cubic spline | Akima spline
Details
Choice of extrapolation method.
Read more about extrapolation methods here: Methods of approximation of function values
Dependencies
-
To select
Cubic splinefor Extrapolation method, you must also selectCubic splinefor Interpolation method. -
To select
Akima splinefor the Extrapolation method, you must also selectAkima splinefor Interpolation method.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
Data type
#
Table data —
table value data type
Inherit: auto | Same as output | Float64 | Float32 | Float16 | Int8 | UInt8 | Int16 | UInt16 | Int32 | UInt32 | Int64 | UInt64 | Int128 | UInt128 | Fixed-point
Details
Specify the data type of the table values.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Table fixed-point type —
fixed-point data type for the table
Data type
Details
Specify the fixed point data type for the table.
Dependencies
To use this parameter, set parameter Table data value Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Breakpoints 1 —
data type for the reference point values for the first measurement
Inherit: auto | Same as input | Float64 | Float32 | Float16 | Int8 | UInt8 | Int16 | UInt16 | Int32 | UInt32 | Int64 | UInt64 | Int128 | UInt128 | Fixed-point
Details
Specify the data type for the reference point values for the first measurement
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Breakpoints 1 fixed-point type —
fixed point data type for the reference point values for the first measurement
Data type
Details
Specify the fixed point data type for the reference point values for the first measurement.
Dependencies
To use this parameter, set the parameters to Breakpoints 1 value Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Fraction —
fraction data type
Inherit: auto | Float64 | Float32 | Fixed-point
Details
Specify the data type of a fraction.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Fraction fixed-point type —
fixed-point fraction data type
Data type
Details
Specify the fixed-point fraction data type.
Dependencies
To use this parameter, set the parameters to Fraction value Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Intermediate results —
intermediate results data type
Inherit: auto | Same as output | Float64 | Float32 | Int8 | UInt8 | Int16 | UInt16 | Int32 | UInt32 | Int64 | UInt64 | Int128 | UInt128 | Fixed-point
Details
Specify the data type of intermediate results.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Intermediate results fixed-point type —
fixed-point data type of intermediate results
Data type
Details
Specify the fixed-point data type of intermediate results.
Dependencies
To use this parameter, set the parameters to Intermediate results value Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Output —
output data type
Inherit: from `Table data` | Same as input | Float64 | Float32 | Float16 | Int8 | UInt8 | Int16 | UInt16 | Int32 | UInt32 | Int64 | UInt64 | Int128 | UInt128 | Fixed-point
Details
Specify the type of output data.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Output fixed-point type —
fixed-point output data type
Data type
Details
Specify the fixed-point output type.
Dependencies
To use this parameter, set parameter Output value Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Integer rounding mode —
rounding mode for fixed-point operations
Ceiling | Convergent | Floor | Nearest | Round | Zero
Details
Select the rounding mode for fixed-point operations. You can select:
-
Floor- rounds both positive and negative numbers downwards (towards negative infinity). -
Ceiling- rounds both positive and negative numbers upwards (towards positive infinity). -
Convergent- rounds the number to the nearest representable value. If the fractional part of a number ends in 5, the number is rounded to the nearest even integer. -
Nearest- rounds the number to the nearest representable value. If the fractional part of the number ends in 5, the number is rounded upwards (towards positive infinity). -
Round- rounds the number to the nearest representable value. If the fractional part of a number ends in 5, positive numbers are rounded upwards (towards positive infinity) and negative numbers are rounded downwards (towards negative infinity).
-
Zero- rounds the number towards zero.
The block parameters are always rounded to the nearest representable value.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Saturate on integer overflow —
overflow action method
Logical
Details
When checked, saturation is applied to all internal block operations, not just the output or result.
| Action | Reasons for taking this action | What happens when | overflows Example |
|---|---|---|---|
Check this box. |
Overflows are possible in your model and you need explicit saturation protection in the generated code. |
Overflows are saturated to the minimum or maximum value that this data type can represent. |
An overflow associated with a signed 8-bit integer may saturate to |
Do not select this check box. |
You want to optimise the efficiency of the generated code. |
Overflows are wrapped in an appropriate value that can be represented by a data type. |
The number |
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |