Re: Package statistics: tricdf (bug?)

Thank you for you reply. This patch fixes tricdf for scalar arguments 
(triinv has also problem). Are the developers aware of it, should we 
file a bug?

On 25/06/2020 01:39, Dmitri A. Sergatskov wrote:
>
>
> On Tue, Jun 23, 2020 at 5:37 AM Evangelos Rozos <[email protected] 
> <mailto:[email protected]>> wrote:
>
>     I think something is wrong with tricdf function (maybe triinv also).
>
>      >> tricdf (0.7, 0.5, 1.0, 0.9)
>
>     ans =  0.16000
>
>     The correct answer should be 0.2.
>
>     MATLAB gives 0.2. This value can be also verified by the geometry
>     of the
>     pdf triangle with base from 0.5 to 1, and height 4 at 0.9. Then, the
>     area of the triangle with base from 0.5 to 0.7 and height 2 (0.7
>     is in
>     the middle of the 0.5 to 0.9 segment) is 0.2.
>
>
> tricdf code has few problems.  For you reported problem this fix 
> should work:
> < area = (x(k_temp) - a).^2 * h;
> ---
> >     area = (x(k_temp) - a).^2 * h / (c - a) / 2 ;
> 74c74
> <     area = (b-x(k_temp)).^2 * h;
> ---
> >     area = (b-x(k_temp)).^2 * h / (b - c) / 2 ;
>
> A similar change should be done for the code segment that deals with 
> the case of
> A,B, and C being arrays rather than scalar. I really do not understand 
> the intent of that code.
> It requires the size of X, A, B, and C to be the same. That does not 
> make much sense to me.
> I think A, B and C should be scalars. I do not think there is a 
> compatible matlab's function.
>
> Dmitri.
> -- 
>
>