2D Lookup table
The 2-D Lookup Table block realizes an approximation of a function z=f(x,y) given x, y, z data points. The first input port corresponds to the first table dimension, x. The Row index input values parameter is a 1-by-m vector of x data points, the Column index input values parameter is a 1-by-n vector of y data points. The table data parameter should be an m-by-n matrix of z data points. Both the row and column vectors must be strictly monotonically increasing (i.e., the value of the next element in the vector is greater than the value of the preceding element).
The block generates output based on the input values using one of these methods selected from the Lookup method parameter list.
- Row index input values
The row values for the table, entered as a row or column vector. The vector values must be strictly monotonic increasing.
Properties : Type 'vec' of size -1.
- Column index input values
The column values for the table, entered as a row or column vector. The vector values must be strictly monotonic increasing.
Properties : Type 'vec' of size -1.
- Table data
Output value table. The matrix size must match the dimensions used in the row index vector and the column index vector.
Properties : Type 'matrix' of size [-1,-1].
- Lookup method(1..5)
Specify the lookup method:
1)Interpolation-extrapolation (Bilinear) method: Performs a bilinear interpolation when inputs are inside the table range and uses a bilinear extrapolation using two endpoints of the table if inputs are outside the table input ranges.
2)Interpolation-endvalues (Bilinear) method: Performs a bilinear interpolation when inputs are inside the table range and uses table endvalues if if inputs are outside the table input ranges.
3)InputNearest: This method does not interpolate or extrapolate. Instead, the elements in row and column vectors nearest the current inputs are found. The corresponding element in the table is then used as the output.
4)InputBelow: This method does not interpolate or extrapolate. Instead, the elements in row and column vectors below the current inputs are found. The corresponding element in the table is then used as the output.
5)InputAbove: This method does not interpolate or extrapolate. Instead, the elements in row and column vectors above the current inputs are found. The corresponding element in the table is then used as the output.
Properties : Type 'vec' of size 1.
- Launch graphic window(y/n)?
If set to 'y', clicking on OK, the 3D plot of the table will be shown. This parameter is automatically reset to 'n'.
Properties : Type 'str' of size 1.
- always active: no
- direct-feedthrough: yes
- zero-crossing: no
- mode: no
- regular inputs:
- port 1 : size [1,1] / type 1
- port 2 : size [1,1] / type 1
- regular outputs:
- port 1 : size [1,1] / type 1
- number/sizes of activation inputs: 0
- number/sizes of activation outputs: 0
- continuous-time state: no
- discrete-time state: no
- object discrete-time state: no
- name of computational function: lookup2d
- SCI/macros/scicos_blocks/NonLinear/LOOKUP2D.sci [view code]
Masoud Najafi INRIA
