Improve efficiency of elseif loop

UpperTempEst=[],
for i=1:11307211
    if Power(i,1) < 360
        TempUpper=prctile(T0,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>360 && Power(i,1)<720
        TempUpper=prctile(T10,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>720 && Power(i,1)<1080
        TempUpper=prctile(T20,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>1080 && Power(i,1)<1440
        TempUpper=prctile(T30,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>1440 && Power(i,1)<1800
        TempUpper=prctile(T40,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>1800 && Power(i,1)<2160
        TempUpper=prctile(T50,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>2160 && Power(i,1)<2520
        TempUpper=prctile(T60,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>2520 && Power(i,1)<2880
        TempUpper=prctile(T70,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>2880 && Power(i,1)<3240
        TempUpper=prctile(T80,95)
        UpperTempEst=[UpperTempEst;i TempUpper]
    elseif Power(i,1)>3240 && Power(i,1)<3600
        TempUpper=prctile(T90,95)
        UpperTempEst=[UpperTempEst;i TempUpper]   
    end
end

I have the above code that relates a power generation to an upper temperature estimate. The power is 1 collumn and 11307211 rows.

I previously split the historic data into ten power bins and have removed outliers from each set. The T-- refers to the temperatures given for each set, and as you can see I am setting the upper limit of the temperature as the 95 percentile.

This manner is just far too computational intesive and I was wondering if anyone has a method that would be much more efficient.

Thanks

Answer 1

[LO]

You don't need the loops, you can use logical indexes. This will speed up the process.If your Power array has 1 dimension you can remove the (:,1).

example:

Power(Power (:,1) < 360) = prctile(T0,95);

Power(Power(:,1)>360 & Power(:,1)<720) = prctile(T10,95);

% etc..

[Patrick Lonergan]

Thanks, works a treat, appreciate the help