Why do I get "Array indices must be positive integers or logical values" error ?

Plot_X = 0:0.01:1
Per = quantile(SUSC,1:-0.01:0)
for i = 1:101
    if i <101
        Plot_Y(i) = sum(CAT(SUSC>=Per(100-i))) / sum(CAT,'all')
    else
        Plot_Y(i) = sum(CAT(SUSC>=0)) / sum(CAT,'all')
    end
end
AUC= round(100*trapz(Plot_X,Plot_Y),1)

the error is in the line 7

Plot_Y(i) = sum(CAT(SUSC>=Per(100-i))) / sum(CAT,'all')

Answer 1

[Voss]

When i is 100, Per(100-i) is Per(0), which causes the error since 0 is not a valid index in MATLAB.