smalltalk numbercrunching

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  • Smalltalk Number Crunching

    Daniel Poon

  • Conventional perception of technical computing is fast becoming out of date

    Take a look at our business Take a look at our technology Take a look at our processes

    What does Smalltalk have to do with Numerically Intensive Tasks?

  • Romax Technology Ltd. & RomaxDesigner

    Our value proposition RomaxDesigner enables

    us to predict the system wide behavior of transmission systems beyond what was previously possible

  • Our Customers

  • What can Romax model?

    Perpendicular Shaft Arrangement

    Planetary Shaft Arrangement

    Parallel Shaft Arrangement

  • F = kx Given

    Stiffness Produced from the stiffnesses of all the components

    Forces Produced by the engine and

    transmitted by the gearbox Solve for

    Deflection How the design will distort in use Large distortions reduce component life

  • VPD (Virtual Product Development)




    Prototype/Physical testing Feedback

    Analysis tells you how your design performs Development of a Complete transmission

    system takes 3-4 years We can reduce that to 1 to 1.5 years

  • The Challenge

    Customers want ever more complex simulation Greater complexity puts greater demands on

    performance The market demands ever shorter lead times and

    shorter development cycles How does Smalltalk help?

  • Why not C#/Java? Speed of Compilation and Late


    Smalltalk's simple syntax is designed to compile like lightning

    With late binding you can run a test even when the system is broken

    Step change in programming style

  • Use double dispatch wherever you want Bounce gui and test behaviour directly off the

    model Matlab like extensions for Domain Experts

    To plot a graph#((1 0) (2 0.5) (3 1.3)) asPoints plot

    To draw an HTML table 'x' || 'y' || 'theta'

    Why not C#/Java? Class extensions

  • Smalltalk

    FortranFortran signals Smalltalk exception

    Smalltalk catches exception

    Fortran resumes

    Smalltalk calls Fortran numerical routine

    End of call out

    Why not C#/Java? - Resumable exceptions

    No need for multiple callbacks We register a single general purpose callback

    that throws a Smalltalk exception Exception hierarchy and scoping rules take care

    of the rest

  • Opportunity for Smalltalk in the technical computing market

    The technical computing market is huge Designed for analysts' own use. Does not address

    product development cycle Smalltalk is fundamentally good for technical

    computing Arbitrary length integers and fractions BlockClosures that serve as a great way of passing

    equations to solvers 'doIt' immediate mode

  • Obsticles for Smalltalk in the technical computing market

    Smalltalk has many quirks. You will need a Smalltalk coach Syntax

    Operator precedence Array syntax

    Lack of native solvers/libraries Floating Point performance Mixed language support

  • Smalltalk is 70 times slower than Fortran for Floating Point ops

    Conventional wisdom Layered Architecture Product model in Smalltalk All engineering calcs in Fortran

    Now profile it We spend 60% of time transferring data back and forth between Smalltalk and Fortran

    Layered Architecture= barrier = difficult to optimize

  • Smalltalk is 70 times slower than Fortran for Floating Point ops

    Smalltalk is just about fast enough (but only just) It can do almost everything we need

    First build it in Smalltalk Then profile itThen optimize the SmalltalkThen use Fortran for the true bottlenecks

    Use a single language = No barriers= Easy to optimize

  • The Chassis/Body System Metaphor

    Two requirements Torsional Rigidity Passenger space

    Two solutions The Chassis provides

    torsional rigidity The Body provides

    passenger space

    Local Optima

  • Global Optimum

    The Monocoque System Metaphor

    Two requirements Torsional Rigidity Passenger space

    One solution Single structure

    integrates torsional rigidity with passenger space

  • FortranCalculation Engine

    SmalltalkProduct Model




    It is not a Technical Challenge

    A traditional team structure will always produce a Layered Architecture with local optima

    To produce a global optimum, both layers have to be designed Simultaneously by the same team

  • Solution Pair Programming between Fortran Guys and Smalltalk Guys

    Produce a globally optimized design Right First Time

    All skills (coding best practices, domain knowledge) immediately at hand

    Zero Lead Time for: Newbie Programmer with

    no domain knowledge Newbie Domain Expert with

    no development skills

  • NumericProduct ModelVisualization

    System interfacing



    Commercial Drivers for Shift Towards Monocoque Architecture

    Customers want ever more complex analysis The market demands shorter lead times and

    shorter development cycles

  • Conclusion

    Why did we want to use Smalltalk in our organization?

    What were the challenges to using Smalltalk in our organization?

    What could the Smalltalk community do to support us?

  • Thank You

    Any Questions?

    Enjoy the rest of the conference

    [email protected]