News & Events
Department Events & Announcements

Events

  • Aug
    17

    Can Gurkan Final Defense August 17: Evolving Code with LLMs: Representation, Selection, and the Limits of Open-Ended Exploration

    Department of Computer Science (CS)

    10:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    This dissertation investigates the use of large language models (LLMs) as variation operators for evolving programs. Whereas a traditional variation operator modifies program syntax without regard to program behavior, an LLM can propose changes informed by the semantics of the code. This capability has enabled new forms of program evolution and produced promising results, yet the behavior of LLM-based evolutionary operators remains comparatively understudied. This dissertation examines three forces that shape the resulting evolutionary process: the representation of candidate programs, the method of selection that determines which candidates persist across generations, and the dynamics of the variation operator itself. Each of these factors influences the capacity for sustained, open-ended exploration.

    To study representation, we evolved agent rules for multi-agent simulations implemented in NetLogo and introduced three benchmark environments for evaluating LLM-generated code in this setting. Three ways of representing the same rule were compared: executable code, code with comments, and pseudocode that a separate model call converts into executable code. Across all three environments, evolving commented code produced the highest-performing agents, while evolving pseudocode produced the lowest-performing agents, indicating that natural language aids the variation operator when it augments executable code rather than replacing it.

    To study selection, we varied the balance between objective performance and behavioral novelty while evolving agent rules. Final fitness was largely unaffected by this balance, but greater emphasis on novelty consistently yielded a higher proportion of qualitatively superior code structures. These findings suggest that diversity-driven search can improve the quality of evolved code, revealing a hidden cost of objective-centric optimization.

    To study the operator itself, we asked whether a language model that repeatedly mutates a program continues to explore new forms or instead returns to recurring structures. Mutation chains were analyzed in the absence of selection pressure within a domain-specific language, varying prompt design, model family, and stochastic replication. The chains converged on restricted regions of program space, with most variation confined to substitutions within recurring structural templates, while a classical genetic programming mutation operator showed no comparable convergence under matched conditions.

    These three forces do not act independently. The representation determines the extent to which the capabilities of the variation operator can be exploited, selection determines which resulting programs persist and become available for further variation, and the dynamics of the operator shape the structures that repeated mutation continues to produce. LLM-driven program evolution can effectively evolve agent rules for multi-agent systems, but its outcomes are sensitive to design choices that are easily left implicit. The selection regime changes the quality of the program structures that survive, while the same semantic capabilities that allow an LLM to transform programs can also introduce a systematic bias toward structural homogeneity. Whether these systems can sustain open-ended exploration depends on the interaction among representation, selection, and variation.

    more less

    TIME Monday, August 17, 2026 at 10:00 AM - 12:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Jensen Smith    jensen.smith@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Oct
    21

    SkAI Colloquium

    SkAI Institute

    11:00 AM Auditorium

    EVENT DETAILSmore info

    TIME Wednesday, October 21, 2026 at 11:00 AM - 12:00 PM

    LOCATION Auditorium   

    ADD TO CALENDAR

    CONTACT Gema Tinoco    Gema.Tinoco@northwestern.edu EMAIL

    CALENDAR SkAI Institute

  • Oct
    22

    Bagel Thursday + Discussion

    Department of Computer Science (CS)

    9:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Thursday, October 22, 2026 at 9:00 AM - 11:00 AM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Oct
    23

    Application for degree due to The Graduate School to receive a degree in Fall

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Friday, October 23, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Oct
    28

    CS Seminar: Beyond heuristics: A meta-scientific agenda for generative AI-powered social research (Aaron Shaw)

    Department of Computer Science (CS)

    12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Wednesday, October 28, 2026 at 12:00 PM - 1:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Oct
    29

    Computer Science Halloween Crafting Social

    Department of Computer Science (CS)

    2:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Thursday, October 29, 2026 at 2:00 PM - 4:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Bella Barrios    marbella.barrios@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    2

    CS Seminar: Quantitative Security Guarantees for Concurrent Systems (Farzaneh Derakhshan)

    Department of Computer Science (CS)

    12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Monday, November 2, 2026 at 12:00 PM - 1:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    2

    Xiling Li CS PhD Final Defense: Efficient, Scalable, and Trustworthy Query Evaluation for Secure Collaborative Analytics

    Department of Computer Science (CS)

    1:00 PM 3501, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Monday, November 2, 2026 at 1:00 PM - 3:00 PM

    LOCATION 3501, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Jensen Smith    jensen.smith@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    4

    CS Seminar: Computational Ecosystems: Advancing Human Values Through Integrative Computing and Changing Practice (Haoqi Zhang)

    Department of Computer Science (CS)

    12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Wednesday, November 4, 2026 at 12:00 PM - 1:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    9

    Distinguished Lecture: Mohit Bansal

    Department of Computer Science (CS)

    12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Monday, November 9, 2026 at 12:00 PM - 1:00 PM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    16

    Regular registration for Winter quarter begins

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, November 16, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Nov
    19

    Bagel Thursday + Discussion

    Department of Computer Science (CS)

    9:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

    EVENT DETAILS

    TIME Thursday, November 19, 2026 at 9:00 AM - 11:00 AM

    LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Nov
    20

    Dissertation, PhD Final Exam, and change of grade forms due to TGS for Fall PhD candidates

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Friday, November 20, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Nov
    25

    Thanksgiving Vacation begins at 6:00 PM (No classes, University offices closed)

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Wednesday, November 25, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Nov
    30

    Fall Classes Resume

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, November 30, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Dec
    4

    Holiday Party

    Department of Computer Science (CS)

    12:00 PM

    EVENT DETAILS

    TIME Friday, December 4, 2026 at 12:00 PM - 2:00 PM

    ADD TO CALENDAR

    CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

    CALENDAR Department of Computer Science (CS)

  • Dec
    5

    Fall classes end

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Saturday, December 5, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Dec
    7

    Fall Exams begin

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, December 7, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Dec
    12

    Fall exams end

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Saturday, December 12, 2026

    ADD TO CALENDAR

    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Dec
    12

    Northwestern Engineering PhD Hooding and Master's Recognition Ceremony

    McCormick School of Engineering and Applied Science

    4:00 PM Pick-Staiger Concert Hall

    EVENT DETAILSmore info

    TIME Saturday, December 12, 2026 at 4:00 PM - 6:00 PM

    LOCATION Pick-Staiger Concert Hall    map it

    ADD TO CALENDAR

    CONTACT Andi Joppie    andi.joppie@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science