Jacob Crossman With help from Bob Marinier Anthony Deschamps New Goal System (NGS) 4.x Jacob Crossman With help from Bob Marinier Anthony Deschamps

NGS 4.x – a new Soar programming abstraction layer Origins/Purpose NGS = New Goal System Initially a few productions and macros to make writing top-state goal forests easier/consistent I wrote NGS 1.0 in 2004 Various improvements and libraries were added by others since then (up to NGS 3.x) Simultaneously I worked on the High-Level Symbolic Representation (HLSR): 2004-2008 Goal was a higher level language Compiled to both Soar and ACT-R Worked but not optimized for Soar programming NGS 4.x – a new Soar programming abstraction layer Still makes goal forests easy (but doesn’t force it) Is a much, much more

Overview NGS 4.x is implemented in TCL 99% of code is written in TCL – if you are writing raw Soar, in most cases, you are doing it wrong Retains some aspects of Soar syntax (e.g. variables, dot notation) RHS functions still use ”raw” Soar It is a library that you load before you load your domain specific code It “compiles” into raw Soar (no TCL runtime required except for debugging) No, there isn’t a specific debugger, but there are two very useful debugging commands: “np” – new print (NGS-aware WME printing) “nps” – new print stack (NGS goal stack printing)

Anatomy of a Production sp “production-name [ngs-match-* <s> …] [ngs-bind <s> foo.bar.position] [ngs-is-X <bar> etc] [ngs-gt <position> x 5.0]  [ngs-create-X <foo> new-attr <new-val>] OR [ngs-create-X-by-operator <s> <foo> new-attr <new-val>] [ngs-tag <new-val> my-tag]”

Wrapping the Left Hand Side All productions start with an “ngs-match” production Always binds the state Each macro is intended to bind the correct items for a given purpose (e.g. create goal, return value, etc) Most productions are followed with one or more “ngs-bind” lines that bind a pattern in working memory Other macros are used to make simple tests (e.g. “ngs-is-type” or “ngs-gt”)

ngs-bind ngs-bind is a mini-language by itself Simplifies complex bind trees Automates variable creation Supports some comparisons Greatly simplifies LHS binding logic and makes easier to read Example: [ngs-bind <s> agent:<me>] [ngs-bind <me> situations.situation!StopAhead \ vehicle-state.stable-velocity:<:$THRESHOLD] TURNS INTO  (<s> ^agent <me>) (<me> ^situations <situations>) (<situations> ^situation <situation>) (<situation> ^type StopAhead) (<me> ^vehicle-state <vehicle-state>) (<vehicle-state> ^stable-velocity < 0.02)

Wrapping the Right Hand Side Right hand sides typically structured as Primary action (o or i-supported) Secondary/supporting actions Common Right Hand Side Macros I-Supported O-Supported Typed Objects ngs-create-typed-object ngs-create-typed-object-by-operator ngs-create-typed-sub-object-by-operator Attributes ngs-create-attribute ngs-create-attribute-by-operator ngs-remove-attribute-by-opeator Tags ngs-tag ngs-create-tag-by-operator ngs-remove-tag-by-operator Goals ngs-create-goal-in-place ngs-create-goal-by-operator ngs-remove-goal-by-operator Other ngs-deep-copy-by-operator ngs-create-output-command-by-operator

Operator Applications NGS 4.x does not require any operator application applications All applications in library Guarantee proper application for complex structure creation (up to 5 levels deep) Properly syncs up with side effects One operator per production (but see side effects on next slide) Operators are all-or-nothing – they either completely construct their object or don’t (no partial applies) Operators can create Deep structure (typed objects and/or deep copy) Links (attributes) Tags Output commands

Operator Side Effects Side effects can be used to create simple structure along with the primary operator application Common: create tags Other: link object somewhere else, set timer, etc Two macros ngs-add-primitive-side-effect ngs-add-tag-side-effect

Example: Counting Teammates sp "my-team*propose*count*expected-num-human-team-members [ngs-match-top-state <s> robo-agent.my-team.member. \ member-info!HumanEntity] [ngs-bind <my-team> expected-num-human-team-members:<cur-count>] [ngs-nex <member> @counted] --> [ngs-create-attribute-by-operator <s> <my-team> \ expected-num-human-team-members "(+ <cur-count> 1)"] [ngs-add-tag-side-effect $NGS_SIDE_EFFECT_ADD <member> counted]" Expanded Code (as viewed from Soar IDE, reformatted for space/clarity): sp {my-team*propose*count*expected-num-human-team-members (state <s> ^superstate nil) (<s> ^robo-agent <robo-agent>) (<robo-agent> ^my-team <my-team>) (<my-team> ^member <member>) (<member> ^member-info <member-info>) (<member-info> ^type HumanEntity) (<my-team> ^expected-num-human-team-members <cur-count>) (<member> -^__tagged*counted) --> (<s> ^operator <o> + =) (<o> ^name (concat |create-wme--| <my-team> |--expected-num-human-team-members--| (+ <cur-count> 1)) ^type atomic) (<o> ^__tagged*ngs*i-supported *YES* +) (<o> ^dest-object <my-team> ^dest-attribute expected-num-human-team-members ^new-obj (+ <cur-count> 1) ^replacement-behavior ngs-replace) (<o> ^__tagged*ngs*intelligent-construction *YES* +) (<o> ^__tagged*ngs*op-create-primitive *YES* +) (<o> ^side-effect <side-effect139> +) (<side-effect139> ^action create ^destination-object <member> ^destination-attribute __tagged*counted ^value *YES* ^replacement-behavior ngs-replace ^type NGS_SideEffect ^my-type NGS_SideEffect)}

Goals Goals as defined by NGS 4.x are top-state structures Goals must be declared using NGS_DeclareGoal (creates many required productions) All goals are indexed multiple ways Primary type Base types Requested decision name Can be o-supported or i-supported (though I recommend i-supported goal stacks) You can also create classic Soar substates, but these are called “states” not “goals”

Decision Goals You can setup persistent decisions using goals as well Works a lot like a persistent state stack, but doesn’t block the reasoning process Also re-decides when the options related to the decision change in any way Easy to link up with an explanation system to explain the decision Multiple parts to the process A goal can request a decision (this is a request for a value to be set for a given attribute) Other goals can be assigned to the decision If more than one goal is assigned to the same decision, a substate is created In the substate, one of the assigned goals is selected (like in an operator tie) I tend to create task goal hierarchies out of i-supported decision goals – decide on sub-tasks and other supporting items like destination, formation, sensor direction, etc

Substates and “Functions” NGS 4.x also supports sub-states ”Free” sub-states with no constraints or restrictions “Function” sub-states Provide for return values Return is all-or-nothing Multiple return values supported Used to implement decision goals sp "achieve-message-handled*propose*handle-mission-message*via-deep-copy [ngs-match-goal <s> AchieveMessageHandled <g>] [ngs-bind <s> robo-agent] [ngs-bind <g> message!MissionMessage.payload] [ngs-is-not-tagged <g> message-copied] --> [ngs-create-function-operator <s> handle-mission-message <o> <ret-vals> \ <g> message-copied] [ngs-create-ret-val-in-place payload <ret-vals> <robo-agent> my-mission] [ngs-tag <o> $RS_DEEP_COPY_MESSAGE]"

Context Variables Context variables can be used to simplify the process of turning raw data into “decision quality” data Sampled Values Periodic Sampled Value: Sample every n milliseconds Stable Value (Change-based sampling): Sample on change > threshold Timed Stable Value: Sample when value doesn’t change for n milli-seconds Binned Values Dynamically Binned Values: Bin value, expand the current bin Statically Binned Values: Bin value based on fixed ranges Decided Values Selected Value: Value selected from multiple alternatives. E.g. the target speed of the vehicle (speed limit, traffic speed, weather speed) Simple Inferred Value: Value inferred from a combination of other values Other Computed Value: value computed from one or more mathematical functions Synced Value: adaptively sample and remap data from input link and automatically keep in sync with the original value

Example of Context Variables NGS_DefineStableValue sample-pool categoryA slow-value-single-delta sp "test*create-stable-value*single-delta   [ngs-match-to-create-context-variable <s> sample-pool categoryA:<pool>]     -->   [ngs-create-stable-value <pool> slow-value-single-delta <s> rapid-value 1.0]" NGS_DefineDynamicBinValue sample-pool categoryA my-speed sp "test*create-dyn-bin-value*my-speed [ngs-match-to-create-context-variable <s> sample-pool categoryA:<pool>] --> [ngs-create-dyn-bin-value <pool> my-speed <s> my-velocity <bins> \ { <s> velocity-delta } $NGS_CTX_VAR_DELTA_TYPE_PERCENT] [ngs-add-dyn-bin <bins> stopped 0.15 {} { 0.0 1.0 } ] [ngs-add-dyn-bin <bins> walking 1.0 stopped] [ngs-add-dyn-bin <bins> jogging 2.0 walking] [ngs-add-dyn-bin <bins> running 3.0 jogging { 0.05 1.5 }] [ngs-add-dyn-bin <bins> sprinting 4.0 running] [ngs-add-dyn-bin <bins> speeding {} sprinting 0.5]"

Nuggets/Coal Nuggets Coal Is easier to read and write Makes writing Soar code faster Reduces bugs (especially low level bugs) It’s efficient and creates expert-level code in many cases LOTs of functionality (I’ve left out many things here including built-in support for explanation) Coal Not a complete language/abstraction Have to debug in raw Soar (but it’s not as hard as you might think) Type system is currently very weak Doesn’t (yet) support semantic and episodic memory directly (likely will by the end of the year)

https://github.com/soartech/new-goal-system-4 Where to Get It Available open source on GitHub https://github.com/soartech/new-goal-system-4 Includes a Developer Guide All of the NGS 4 basics are covered More advanced features like ”Decision Goals” and “Context Variables” are not covered yet For debugging to work, you will need a recent nightly build of Soar (or maybe the newest release ?) Use NGS 4.x with Soar IDE – you get code expansion and error checking