OpenEuphoria

Re: Being stupid - need help

• Posted by petelomax Apr 27, 2020
• 1076 views

read it and weep (Seems to pass your tests 100% anyway - changing 0-based indexing to 1-based is a bit of a black art)

-- Calculates the mean squared error  
public function MeanSquaredError(sequence truth, prediction) 
    integer n = length(truth) 
    atom rss = sum(sq_power(sq_sub(truth,prediction[1..n]),2))/(n-1) 
    return rss 
end function 
 
public function HoltWinterspredictMult(sequence data, atom alpha, delta, gamma, integer seasonLength) 
    integer datalen = length(data) 
    sequence {A,B,S} @= repeat(0.0, datalen) 
    atom averageFirstSeason = sum(data[1..seasonLength])/seasonLength 
    B[seasonLength] = averageFirstSeason 
    S[1..seasonLength] = sq_div(data[1..seasonLength],averageFirstSeason) 
    for i=seasonLength+1 to datalen do 
        B[i] = alpha*(data[i]/S[i-seasonLength])+(1-alpha)*(B[i-1]+A[i-1]) 
        A[i] = gamma*(B[i]-B[i-1])+(1-gamma)*A[i-1] 
        S[i] = delta*(data[i]/B[i])+(1-delta)*S[i-seasonLength] 
    end for 
    sequence forecast = repeat(0.0, datalen+seasonLength) 
    for i=seasonLength+1 to datalen do 
        forecast[i] = (A[i-1]+B[i-1])*S[i-seasonLength] 
    end for 
    for i=datalen+1 to datalen+seasonLength do 
        forecast[i] = (B[datalen]+(i-datalen)*A[datalen])*S[i-seasonLength] 
    end for 
    {A,B,S} @= {} 
    atom sse = MeanSquaredError(data, forecast) 
    return {sse, forecast} 
end function 
 
public function HoltWinterspredictAdd(sequence data, atom alpha, delta, gamma, integer seasonLength) 
    integer datalen = length(data) 
    sequence {A,B,S} @= repeat(0.0, datalen) 
    atom averageFirstSeason = sum(data[1..seasonLength])/seasonLength 
    B[seasonLength] = averageFirstSeason 
    S[1..seasonLength] = sq_sub(data[1..seasonLength],averageFirstSeason) 
    for i=seasonLength+1 to datalen do 
        B[i] = alpha*(data[i]-S[i-seasonLength])+(1-alpha)*(B[i-1]+A[i-1]) 
        A[i] = gamma*(B[i]-B[i-1])+(1-gamma)*A[i-1] 
        S[i] = delta*(data[i]-B[i])+(1-delta)*S[i-seasonLength] 
    end for 
    sequence forecast = repeat(0.0, datalen+seasonLength) 
    for i=seasonLength+1 to datalen do 
        forecast[i] = A[i-1]+B[i-1]+S[i-seasonLength] 
    end for 
    for i=datalen+1 to datalen+seasonLength do 
        forecast[i] = B[datalen]+((i-datalen)*A[datalen])+S[i-seasonLength] 
    end for 
    {A,B,S} @= {} 
    atom sse = MeanSquaredError(data, forecast) 
    return {sse, forecast} 
end function