compare

Class: FunctionApproximation.LUTSolution
Namespace: FunctionApproximation

Compare numerical results of FunctionApproximation.LUTSolution to original function or lookup table

Syntax

data = compare(solution)


Description

data = compare(solution) plots the difference between the data contained in the FunctionApproximation.LUTSolution object, solution, and the original lookup table, function, or Math Function block.

Input Arguments

solution — Solution to compare original behavior against

FunctionApproximation.LUTSolution object

The solution to compare original behavior against, specified as a FunctionApproximation.LUTSolution object.

Output Arguments

data — Structure containing data comparing original and the solution

structure

Structure containing data comparing the original function or lookup table and the approximation contained in the solution.

Examples

Compare Function Approximation to Original Function

Create a FunctionApproximation.Problem object defining the function you want to approximate.

problem = FunctionApproximation.Problem('tanh')

problem = 
  1×1 FunctionApproximation.Problem with properties:

    FunctionToApproximate: @(x)tanh(x)
           NumberOfInputs: 1
               InputTypes: "numerictype(1,16,12)"
         InputLowerBounds: -8
         InputUpperBounds: 8
               OutputType: "numerictype(1,16,15)"
                  Options: [1×1 FunctionApproximation.Options]

Use default values for all other options. Approximate the tanh function using 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 |             64 |        0 |          2 |              16 |           16 |             EvenSpacing |     7.812500e-03, 7.229091e-01 |
|   1 |           1248 |        1 |         76 |              16 |           16 |             EvenSpacing |     7.812500e-03, 4.368265e-03 |
|   2 |           1232 |        1 |         75 |              16 |           16 |             EvenSpacing |     7.812500e-03, 4.439035e-03 |
|   3 |            944 |        1 |         57 |              16 |           16 |             EvenSpacing |     7.812500e-03, 7.780470e-03 |
|   4 |            928 |        1 |         56 |              16 |           16 |             EvenSpacing |     7.812500e-03, 5.383741e-03 |
|   5 |            656 |        0 |         39 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.678519e-02 |
|   6 |            640 |        0 |         38 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.660649e-02 |
|   7 |            784 |        1 |         47 |              16 |           16 |             EvenSpacing |     7.812500e-03, 7.743777e-03 |
|   8 |            704 |        1 |         42 |              16 |           16 |             EvenSpacing |     7.812500e-03, 7.805676e-03 |
|   9 |            672 |        1 |         40 |              16 |           16 |             EvenSpacing |     7.812500e-03, 7.809550e-03 |
|  10 |            368 |        0 |         21 |              16 |           16 |             EvenSpacing |     7.812500e-03, 4.855583e-02 |
|  11 |            512 |        0 |         30 |              16 |           16 |             EvenSpacing |     7.812500e-03, 2.773526e-02 |
|  12 |            592 |        0 |         35 |              16 |           16 |             EvenSpacing |     7.812500e-03, 2.088471e-02 |
|  13 |            624 |        0 |         37 |              16 |           16 |             EvenSpacing |     7.812500e-03, 1.870074e-02 |
|  14 |            384 |        1 |         12 |              16 |           16 |          ExplicitValues |     7.812500e-03, 7.812317e-03 |
|  15 |            384 |        0 |         12 |              16 |           16 |          ExplicitValues |     7.812500e-03, 1.196141e-02 |
|  16 |            384 |        1 |         12 |              16 |           16 |          ExplicitValues |     7.812500e-03, 7.812317e-03 |

Best Solution
|  ID |  Memory (bits) | Feasible | Table Size | Breakpoints WLs | TableData WL | BreakpointSpecification |             Error(Max,Current) |
|  14 |            384 |        1 |         12 |              16 |           16 |          ExplicitValues |     7.812500e-03, 7.812317e-03 |

solution = 
  1×1 FunctionApproximation.LUTSolution with properties:

          ID: 14
    Feasible: "true"

Compare the original function and the function approximation.

data = compare(solution)

data = struct with fields:
    Breakpoints: [65536×1 double]
       Original: [65536×1 double]
    Approximate: [65536×1 double]

Version History

Introduced in R2018a