replaceWithApproximate

Class: FunctionApproximation.LUTSolution
Package: FunctionApproximation

Replace block with the generated lookup table approximation

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Syntax

replaceWithApproximate(solution)

Description

replaceWithApproximate(solution) replaces the simulink block with its lookup table approximation, generated using the approximate method of the FunctionApproximation.LUTSolution object.

Input Arguments

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Solution to replace the source block, specified as a FunctionApproximation.LUTSolution object.

Examples

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Open Script

This example shows how to approximate a block using a lookup table approximation, replace the original block with the approximation, and then revert the block back to its original state.

Open the model containing the block to approximate. In this example, replace the tan block with a lookup table approximation.

open_system('ex_luto_approx')

Create a FunctionApproximation.Problem object specifying what you want to approximate.

problem = FunctionApproximation.Problem('ex_luto_approx/Trigonometric Function')

problem = 

  1x1 FunctionApproximation.Problem with properties:

    FunctionToApproximate: 'ex_luto_approx/Trigonometric Function'
           NumberOfInputs: 1
               InputTypes: "numerictype('double')"
         InputLowerBounds: -1.5083
         InputUpperBounds: 1.5083
               OutputType: "numerictype('double')"
                  Options: [1x1 FunctionApproximation.Options]

Use default values for all other options. To approximate the block use the solve method.

solution = solve(problem)

|  ID |  Memory (bits) | Feasible | Table Size | Breakpoints WLs | TableData WL | BreakpointSpecification |             Error(Max,Current) | 
|   0 |             48 |        0 |          2 |               8 |           16 |             EvenSpacing |     7.812500e-03, 1.146582e+01 |
|   1 |            800 |        0 |         49 |               8 |           16 |             EvenSpacing |     7.812500e-03, 4.497030e-01 |
|   2 |           1584 |        1 |         98 |               8 |           16 |             EvenSpacing |     7.812500e-03, 1.016505e-05 |
|   3 |            640 |        0 |         39 |               8 |           16 |             EvenSpacing |     7.812500e-03, 3.533199e+00 |
|   4 |            416 |        0 |         25 |               8 |           16 |             EvenSpacing |     7.812500e-03, 4.497030e-01 |
|   5 |           1056 |        0 |         65 |               8 |           16 |             EvenSpacing |     7.812500e-03, 4.497030e-01 |
|   6 |             64 |        0 |          2 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.145654e+01 |
|   7 |            768 |        1 |         46 |              16 |           16 |             EvenSpacing |     7.812500e-03, 2.192364e-04 |
|   8 |            752 |        1 |         45 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.220687e-04 |
|   9 |            592 |        1 |         35 |              16 |           16 |             EvenSpacing |     7.812500e-03, 2.388241e-04 |
|  10 |            576 |        1 |         34 |              16 |           16 |             EvenSpacing |     7.812500e-03, 6.201875e-05 |
|  11 |            416 |        0 |         24 |              16 |           16 |             EvenSpacing |     7.812500e-03, 8.559014e-01 |
|  12 |            400 |        0 |         23 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.008229e+00 |
|  13 |            496 |        0 |         29 |              16 |           16 |             EvenSpacing |     7.812500e-03, 2.136958e-01 |
|  14 |            528 |        1 |         31 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.018354e-04 |
|  15 |            512 |        0 |         30 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.037605e-01 |
|  16 |             80 |        0 |          2 |               8 |           32 |             EvenSpacing |     7.812500e-03, 1.146600e+01 |
|  17 |             48 |        0 |          2 |               8 |           16 |         EvenPow2Spacing |     7.812500e-03, 1.146582e+01 |
|  18 |             64 |        0 |          2 |              16 |           16 |         EvenPow2Spacing |     7.812500e-03, 1.145654e+01 |
|  19 |             80 |        0 |          2 |               8 |           32 |         EvenPow2Spacing |     7.812500e-03, 1.146600e+01 |
|  20 |             96 |        0 |          2 |              16 |           32 |         EvenPow2Spacing |     7.812500e-03, 1.145661e+01 |
|  21 |            128 |        0 |          2 |              32 |           32 |         EvenPow2Spacing |     7.812500e-03, 1.145660e+01 |
|  22 |             96 |        0 |          2 |              32 |           16 |         EvenPow2Spacing |     7.812500e-03, 1.145654e+01 |
|  23 |            216 |        0 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 1.057648e-02 |
|  24 |            216 |        1 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 7.187595e-03 |
|  25 |            216 |        0 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 1.057648e-02 |
|  26 |            216 |        0 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 1.036807e-02 |
|  27 |            216 |        1 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 7.187595e-03 |
|  28 |            144 |        0 |          2 |               8 |           64 |             EvenSpacing |     7.812500e-03, 1.195947e+01 |
|  29 |            144 |        0 |          2 |               8 |           64 |         EvenPow2Spacing |     7.812500e-03, 1.195947e+01 |

Best Solution
|  ID |  Memory (bits) | Feasible | Table Size | Breakpoints WLs | TableData WL | BreakpointSpecification |             Error(Max,Current) |
|  24 |            216 |        1 |          9 |               8 |           16 |          ExplicitValues |     7.812500e-03, 7.187595e-03 |


solution = 

  1x1 FunctionApproximation.LUTSolution with properties:

          ID: 24
    Feasible: "true"

Generate a Simulink™ subsystem containing the lookup table approximation using the approximate method.

approximate(solution)

Replace the original block with the approximation.

replaceWithApproximate(solution)

You can revert the system back to its original state using the revertToOriginal method.

revertToOriginal(solution)

See Also

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Topics

Introduced in R2018b

Fixed-Point Designer Documentation
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