MATLAB: Does the Lookup Table(n-D) block error in Simulink 7.0 (R2007b)

simulink

I am using Simulink 7.0 (R2007b), and when I use the Lookup Table(n-D) block in any model, I get an error saying:

 'sfun_lookupnd.c' not found.

I noticed that when I right click and select 'look under mask' for this block, and choose Edit S-function, it is looking for sfun_lookupnd.c, but is not able to find it.

Best Answer

The Lookup Table (n-D) block in Simulink 7.0 (R2007b) does not use a masked S-function underneath. In Simulink 6.6 (R2007a) and previous versions the lookup Table (n-D) had an underlying S-function.

For a later version such as R2007b showing the masked S-function behavior indicates that Simulink is picking up libraries from an earlier version installed in the machine.

As a workaround, please try one of the following:

a) Use SLUPDATE to replace blocks from previous releases with latest versions

b) Make sure that the current version's Simulink libraries are on top in MATLAB path to force Simulink to pick up the new version of the library.

Please execute the following in the MATLAB Command Window:

[matlabroot  '\toolbox\simulink\blocks']

This will return the path of the library blocks in which Lookup tables reside.

Please add this path on top of the existing MATLAB path. To do this, navigate to File -> Set Path-> Add with Sub Folders.

Make sure that this path (which was returned in the Command Window earlier) is placed higher in the path than the older version of Simulink. Then save the path and restart MATLAB.

Simulink should now pick up the newer version of the Lookup table library.

Related Solutions

MATLAB: How to implement a 2-D or n-D dynamic lookup table block in Simulink 7.8 ( R2011b)

This can be done by connecting 'n' number of "Prelookup" blocks to an "Interpolation Using Prelookup" block.

Please find attached a library model 'Dynamic_2D_Lookup_Table.mdl' that contains a Dynamic 2-D Lookup Table block and a test model 'TS_Dynamic_2D_Lookup.mdl' that uses this block.

'Look Under Mask' to view the implementation of the custom library block. You can extend the same functionality to create 3-D and 4-D dynamic lookup table blocks. Change the 'Number of Table Dimensions' parameter of the Interpolation using Prelookup' block to 3 or 4 and use the corresponding number of 'Pre-Lookup' blocks.

Inside the custom library block, the 'Table Data Source' parameter of the 'Interpolation using Prelookup' block is set to 'From Input'. It is this feature that allows a dynamic implementation of the lookup table. Please note that this feature is not available in R2010a and earlier releases. Using the library block in these versions will crash MATLAB. There are no workaround for the earlier versions.

MATLAB: How to use FIND_SYSTEM to find the Lookup Table (n-D) block in a model in Simulink 6.6 (R2007a)

The Lookup Table (n-D) block is actually an S-function block that points to the “sfun_lookupnd” S-Function. Therefore it can be found by specifying the block type to be S-Function, as shown below:

>> find_system(gcs,'blocktype','S-Function')
 ans = 
     'testfindsys/Lookup
 Table (n-D)'

The specific Lookup Table (n-D) blocks can also be found by looking for the S-function name “sfun_lookupnd”, using the ‘FunctionName’ parameter, as shown below:

>> find_system(gcs,'FunctionName','sfun_lookupnd')
 ans = 
     'testfindsys/Lookup
 Table (n-D)'

Best Answer

Related Solutions

MATLAB: How to implement a 2-D or n-D dynamic lookup table block in Simulink 7.8 ( R2011b)

MATLAB: How to use FIND_SYSTEM to find the Lookup Table (n-D) block in a model in Simulink 6.6 (R2007a)

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