Talk on Fast sheet-defined functions in spreadsheets

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Professor Peter Sestoft will give a talk on fast sheet-defined functions in spreadsheets, se abstract below.

Time: August 26, 11-12 am, Department of Computer Science, Selma Lagerlöfs Vej 300, 9220 Aalborg East, Room 02.13.

 

Title and abstract: Fast sheet-defined functions in spreadsheets

Spreadsheets appeal to millions of users because they are concrete, declarative and non-iterative. However, the absence of abstraction facilities leads to models that are unwieldy, slow, error-ridden and difficult to maintain. Our goal is to allow users to define new functions within the familiar spreadsheet paradigm, without resorting to external languages such as VBA in Excel, and with performance comparable to built-in functions.

We present a prototype spreadsheet implementation that achieves these goals, based on the concept of sheet-defined function. Type analysis and continuation-based compilation are used to generate efficient .NET bytecode from such sheet-defined functions at runtime. Thanks to the platform's just-in-time compiler the implementation is fast. We give several examples of useful functions definable this way. We show that higher-order and recursive sheet-defined functions have natural uses. For instance, the Goal Seek numerical equation solver, and several other built-in functions from Excel, can be user-defined in our framework. Since sheet-defined functions are declarative, they can be specialized (partially evaluated) quite easily. For the same reason, it is relatively easy to exploit the near-explicit parallelism of spreadsheet models. We mention some preliminary experiments with multicore computers and graphics processors (GPGPUs)

 

 

 

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