diff options
Diffstat (limited to 'calc.go')
| -rw-r--r-- | calc.go | 50 |
1 files changed, 50 insertions, 0 deletions
@@ -430,6 +430,8 @@ type formulaFuncs struct { // FV // FVSCHEDULE // GAMMA +// GAMMA.DIST +// GAMMADIST // GAMMALN // GAUSS // GCD @@ -6038,6 +6040,54 @@ func (fn *formulaFuncs) GAMMA(argsList *list.List) formulaArg { return newErrorFormulaArg(formulaErrorVALUE, "GAMMA requires 1 numeric argument") } +// GAMMAdotDIST function returns the Gamma Distribution, which is frequently +// used to provide probabilities for values that may have a skewed +// distribution, such as queuing analysis. +// +// GAMMA.DIST(x,alpha,beta,cumulative) +// +func (fn *formulaFuncs) GAMMAdotDIST(argsList *list.List) formulaArg { + if argsList.Len() != 4 { + return newErrorFormulaArg(formulaErrorVALUE, "GAMMA.DIST requires 4 arguments") + } + return fn.GAMMADIST(argsList) +} + +// GAMMADIST function returns the Gamma Distribution, which is frequently used +// to provide probabilities for values that may have a skewed distribution, +// such as queuing analysis. +// +// GAMMADIST(x,alpha,beta,cumulative) +// +func (fn *formulaFuncs) GAMMADIST(argsList *list.List) formulaArg { + if argsList.Len() != 4 { + return newErrorFormulaArg(formulaErrorVALUE, "GAMMADIST requires 4 arguments") + } + var x, alpha, beta, cumulative formulaArg + if x = argsList.Front().Value.(formulaArg).ToNumber(); x.Type != ArgNumber { + return x + } + if x.Number < 0 { + return newErrorFormulaArg(formulaErrorNUM, formulaErrorNUM) + } + if alpha = argsList.Front().Next().Value.(formulaArg).ToNumber(); alpha.Type != ArgNumber { + return alpha + } + if beta = argsList.Back().Prev().Value.(formulaArg).ToNumber(); beta.Type != ArgNumber { + return beta + } + if alpha.Number <= 0 || beta.Number <= 0 { + return newErrorFormulaArg(formulaErrorNUM, formulaErrorNUM) + } + if cumulative = argsList.Back().Value.(formulaArg).ToBool(); cumulative.Type == ArgError { + return cumulative + } + if cumulative.Number == 1 { + return newNumberFormulaArg(incompleteGamma(alpha.Number, x.Number/beta.Number) / math.Gamma(alpha.Number)) + } + return newNumberFormulaArg((1 / (math.Pow(beta.Number, alpha.Number) * math.Gamma(alpha.Number))) * math.Pow(x.Number, (alpha.Number-1)) * math.Exp(0-(x.Number/beta.Number))) +} + // GAMMALN function returns the natural logarithm of the Gamma Function, Γ // (n). The syntax of the function is: // |