1 / 23

Tree Evaluation Overview

Tree Evaluation Overview. September 17 th , 2013 Erik Fredericks. Overview. Step-by-step detail of tree evaluation process Discussion throughout Issues in generating trees that fully satisfy all pre/post conditions. Tree Setup. Terminals Objects defined with: Starting state

danyl
Download Presentation

Tree Evaluation Overview

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tree Evaluation Overview September 17th, 2013 Erik Fredericks

  2. Overview • Step-by-step detail of tree evaluation process • Discussion throughout • Issues in generating trees that fully satisfy all pre/post conditions

  3. Tree Setup • Terminals • Objects defined with: • Starting state • Target condition

  4. Tree Setup • Terminals • Objects defined with: • Starting state • Target condition • Examples: • Starting state: FLOAT-ARRAY (Source pre-condition) • Target state: INT-ARRAY (Target pre-condition) • Starting state: INT (Source pre-condition) • Target state: ARRAY-SIZE (Target pre-condition)

  5. Node Evaluation • Role transformation • Check if the current node satisfies the target condition

  6. Node Evaluation • Role transformation • Check if the current node satisfies the target condition • If true • Increment object fitness by a large amount • Note that condition is satisfied

  7. Node Evaluation • Role transformation • Check if the current node satisfies the target condition • If true • Increment object fitness by a large amount • Note that condition is satisfied • Else • If the transformation was valid • Increment object fitness by a small amount • “We’re heading in the right direction” • If it was not valid • Decrement object fitness by a decent amount • If condition was previously satisfied, penalize further as we’re moving away from a correct answer • Note that condition is currently unsatisfied

  8. Node Evaluation • Data transformation • Check that necessary roles are available for evaluation • GET-HIGH-INDEX requires an array and an array size • If so, increase object fitness • Otherwise, penalize

  9. Fitness Calculation • Fitness values for each terminal object is summed, and the inverse is calculated • EpochX considers 0.0 to be the best fitness • Software engineering metrics could further be applied here in the future • Reduce size of tree • Complexify tree • Etc.

  10. An Ideal Tree WRAPPER FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  11. An Ideal Tree WRAPPER FLOAT2INT INT2FLOAT ARR2INDEX (Start) FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  12. An Ideal Tree WRAPPER • Convert a float array to an int array • Target role is int array • FLOAT-ARRAY.fitness += 10.0 FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  13. An Ideal Tree WRAPPER • Get the high index of an array • Children are an array and an int • INT.fitness += 10.0 FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  14. An Ideal Tree WRAPPER Tree is penalized out of existence if 3rd parameter is not a target-method FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  15. An Ideal Tree WRAPPER • Convert an int array to a float array • Target role is float array • INT-ARRAY.fitness += 10.0 FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  16. An Ideal Tree WRAPPER Overall fitness 1.0 / (FLOAT-ARRAY.fitness + INT.fitness + INT-ARRAY.fitness) FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  17. An Ideal Tree WRAPPER CHAR2INT Fitness here would simply be incremented, as a FLOAT2CHAR is a valid transform FLOAT2CHAR INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  18. An Ideal Tree WRAPPER • The composition node (always root) looks for (mergeSort): • 4 conditions to be satisfied • FLOAT-ARRAY -> INT-ARRAY • ARRAY-HIGH-INDEX • TARGET-METHOD • INT-ARRAY -> FLOAT-ARRAY FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  19. An Ideal Tree WRAPPER • What the results show: • Generally, 2/3 of the conditions are satisfied (never all 3) • Evolution finding simplest path, or simplest path with an extra NOP • (not chaining transforms) FLOAT2INT INT2FLOAT ARR2INDEX FLOAT-ARRAY FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  20. A Non-Ideal Tree WRAPPER CHAR2VOID INT2FLOAT NOP FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  21. A Non-Ideal Tree WRAPPER Penalize for an invalid transform CHAR2VOID INT2FLOAT NOP FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  22. A Non-Ideal Tree WRAPPER Penalize for an unsatisfied condition CHAR2VOID INT2FLOAT NOP FLOAT-ARRAY INT TARGET-METHOD INT-ARRAY

  23. Discussion • Evaluation methods • Use of terminals • Other?

More Related