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Subject: Re: [office-formula] IRR Office-1054
Hi Patrick, On Tuesday, 2010-03-30 17:17:06 -0400, Patrick Durusau wrote: > Note that the syntax include the default 0.1 value. > > Rob has proposed: > >> Semantics: Compute the internal rate of return for a series of cash >> flows. >> >> The result of IRR is the rate at which the NPV() function will return >> zero with the given Values. >> >> There is no closed form for IRR. Implementations typically return an >> approximate solution using an iterative method, in which case the >> Guess parameter may be used to initialize the iteration. If the >> implementation is unable to converge on a solution given a particular >> Guess, it may return an error. > > OK, no problem with first two sentences. > > What to do with the default value in the syntax if we drop it from > semantics? Keep it. > Further suggestion, why not simply say: > > "If provided, Guess is an estimate of the interest rate to start the > iterative computation. If omitted, the value 0.1 (10%) is assumed. If an > evaluator is unable to converge on a solution given a particular Guess, > it may return an error." Looks good to me. Eike -- Automatic string conversions considered dangerous. They are the GOTO statements of spreadsheets. --Robert Weir on the OpenDocument formula subcommittee's list.