# replaceWithApproximate

Class: FunctionApproximation.LUTSolution
Package: FunctionApproximation

Replace block with the generated lookup table approximation

Since R2018b

## 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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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) ```
```Searching for fixed-point solutions. | ID | Memory (bits) | Feasible | Table Size | Breakpoints WLs | TableData WL | BreakpointSpecification | Error(Max,Current) | | 0 | 48 | 0 | 2 | 8 | 16 | EvenSpacing | 7.812500e-03, 9.471100e+00 | | 1 | 800 | 0 | 49 | 8 | 16 | EvenSpacing | 7.812500e-03, 4.497029e-01 | | 2 | 1584 | 1 | 98 | 8 | 16 | EvenSpacing | 7.812500e-03, 1.016505e-05 | | 3 | 1056 | 0 | 65 | 8 | 16 | EvenSpacing | 7.812500e-03, 4.497029e-01 | | 4 | 544 | 0 | 33 | 8 | 16 | EvenSpacing | 7.812500e-03, 4.497029e-01 | | 5 | 416 | 0 | 25 | 8 | 16 | EvenSpacing | 7.812500e-03, 4.497029e-01 | | 6 | 368 | 0 | 22 | 8 | 16 | EvenSpacing | 7.812500e-03, 4.534664e+00 | | 7 | 64 | 0 | 2 | 16 | 16 | EvenSpacing | 7.812500e-03, 9.517788e+00 | | 8 | 768 | 1 | 46 | 16 | 16 | EvenSpacing | 7.812500e-03, 2.192364e-04 | | 9 | 752 | 1 | 45 | 16 | 16 | EvenSpacing | 7.812500e-03, 1.220687e-04 | | 10 | 592 | 1 | 35 | 16 | 16 | EvenSpacing | 7.812500e-03, 2.388241e-04 | | 11 | 576 | 1 | 34 | 16 | 16 | EvenSpacing | 7.812500e-03, 6.201875e-05 | | 12 | 416 | 0 | 24 | 16 | 16 | EvenSpacing | 7.812500e-03, 8.559014e-01 | | 13 | 400 | 0 | 23 | 16 | 16 | EvenSpacing | 7.812500e-03, 1.008229e+00 | | 14 | 496 | 0 | 29 | 16 | 16 | EvenSpacing | 7.812500e-03, 2.136958e-01 | | 15 | 528 | 1 | 31 | 16 | 16 | EvenSpacing | 7.812500e-03, 1.018354e-04 | | 16 | 512 | 0 | 30 | 16 | 16 | EvenSpacing | 7.812500e-03, 1.037605e-01 | | 17 | 288 | 0 | 16 | 16 | 16 | EvenSpacing | 7.812500e-03, 2.391904e+00 | | 18 | 464 | 0 | 27 | 16 | 16 | EvenSpacing | 7.812500e-03, 4.491186e-01 | | 19 | 80 | 0 | 2 | 8 | 32 | EvenSpacing | 7.812500e-03, 9.471052e+00 | | 20 | 48 | 0 | 2 | 8 | 16 | EvenPow2Spacing | 7.812500e-03, 1.146582e+01 | | 21 | 416 | 0 | 25 | 8 | 16 | EvenPow2Spacing | 7.812500e-03, 4.497029e-01 | | 22 | 224 | 0 | 13 | 8 | 16 | EvenPow2Spacing | 7.812500e-03, 2.887487e+00 | | 23 | 64 | 0 | 2 | 16 | 16 | EvenPow2Spacing | 7.812500e-03, 1.145654e+01 | | 24 | 432 | 0 | 25 | 16 | 16 | EvenPow2Spacing | 7.812500e-03, 6.957588e-01 | | 25 | 240 | 0 | 13 | 16 | 16 | EvenPow2Spacing | 7.812500e-03, 3.221296e+00 | | 26 | 80 | 0 | 2 | 8 | 32 | EvenPow2Spacing | 7.812500e-03, 1.146600e+01 | | 27 | 432 | 0 | 13 | 8 | 32 | EvenPow2Spacing | 7.812500e-03, 2.887556e+00 | | 28 | 96 | 0 | 2 | 16 | 32 | EvenPow2Spacing | 7.812500e-03, 1.145661e+01 | | 29 | 448 | 0 | 13 | 16 | 32 | EvenPow2Spacing | 7.812500e-03, 3.221186e+00 | | 30 | 128 | 0 | 2 | 32 | 32 | EvenPow2Spacing | 7.812500e-03, 1.145660e+01 | | 31 | 480 | 0 | 13 | 32 | 32 | EvenPow2Spacing | 7.812500e-03, 3.220685e+00 | | 32 | 96 | 0 | 2 | 32 | 16 | EvenPow2Spacing | 7.812500e-03, 1.145654e+01 | | 33 | 464 | 0 | 25 | 32 | 16 | EvenPow2Spacing | 7.812500e-03, 6.951333e-01 | | 34 | 272 | 0 | 13 | 32 | 16 | EvenPow2Spacing | 7.812500e-03, 3.220611e+00 | | 35 | 216 | 1 | 9 | 8 | 16 | ExplicitValues | 7.812500e-03, 9.900552e-04 | | 36 | 192 | 0 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.142949e-02 | | 37 | 192 | 0 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.142949e-02 | | 38 | 192 | 0 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.142949e-02 | | 39 | 192 | 0 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.142949e-02 | | 40 | 192 | 1 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.383244e-03 | Searching for floating-point solutions. | 41 | 64 | 0 | 2 | 16 | 16 | EvenSpacing | 7.812500e-03, 9.424033e+00 | | 42 | 768 | 0 | 46 | 16 | 16 | EvenSpacing | 7.812500e-03, 9.531209e-01 | | 43 | 752 | 1 | 45 | 16 | 16 | EvenSpacing | 7.812500e-03, 3.864191e-05 | | 44 | 160 | 0 | 2 | 16 | 64 | EvenSpacing | 7.812500e-03, 9.421379e+00 | | 45 | 64 | 0 | 2 | 16 | 16 | EvenPow2Spacing | 7.812500e-03, 1.145605e+01 | | 46 | 160 | 0 | 2 | 16 | 64 | EvenPow2Spacing | 7.812500e-03, 1.145598e+01 | Best Solution | ID | Memory (bits) | Feasible | Table Size | Breakpoints WLs | TableData WL | BreakpointSpecification | Error(Max,Current) | | 40 | 192 | 1 | 8 | 8 | 16 | ExplicitValues | 7.812500e-03, 1.383244e-03 | solution = 1x1 FunctionApproximation.LUTSolution with properties: ID: 40 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) ```

## Version History

Introduced in R2018b