Sorry for the comment !
I use Evince

Le dim. 12 mai 2024 à 17:30, Hans Hagen <j.hagen@xs4all.nl> a écrit :
On 5/12/2024 3:57 PM, Fabrice Couvreur wrote:
> Hi,
> When I want to draw the curve which corresponds to n=60 (blue curve), it
> doesn't seem possible: I don't understand.
> Thanks
> Fabrice
>
>   \startMPpage[offset=1DK]
>
>            numeric u;
>            u = 6cm;
>
>            interim linejoin := mitered;
>            interim ahangle := 30;
>
>            path xx, yy;
>            xx = ( (-0.3,0) -- 1.4 right) scaled u;
>            yy = ( (-0.1,0) -- 1.8 right) rotated 90 scaled u;
>
>            def compute_curve(suffix f)(expr xmin, xmax, xinc) =
>                ((xmin,f(xmin))
>                for x=xmin+xinc step xinc until xmax:
>                     .. (x,f(x))
>                endfor)
>            enddef;
>
>
>            for i = 1 upto 4:
>
>            vardef f(expr x) =x+exp(-i*x) enddef;
>
>            path curve;
>
>            curve = compute_curve(f,-0.4,1.4,0.0001) scaled u;
>
>            draw curve;
>
>            endfor;
>
>            vardef f(expr x) =x+exp(-6*x) enddef;
>
>            path curve;
>
>            curve = compute_curve(f,-0.4,1.4,0.0001) scaled u;
>
>            draw curve;
>
>            vardef f(expr x) =x+exp(-15*x) enddef;
>
>            path curve;
>
>            curve = compute_curve(f,-0.4,1.4,0.0001) scaled u;
>
>            draw curve;
>
>
>            vardef f(expr x) =x+exp(-60*x) enddef;
>
>            path curve;
>
>            curve = compute_curve(f,-0.4,1.4,0.0001) scaled u; ->>>>> not
> drawn

best put a comment before the ->>>>>>>

>            draw curve withcolor blue;
>
>
>            drawarrow (0,0) -- (u,0) withpen pencircle scaled 1.5bp;
>            drawarrow (0,0) -- (0,u) withpen pencircle scaled 1.5bp;
>
>
>            label.urt("A",(0,1u));
>
>            draw xx;
>            draw  yy;
>
>            draw (1u,0) -- (1u,1.8u);
>
>
>            label.llft("0",(0,0));
>
>             vardef mark_y_axis(expr value, name) =
>              save p; pair p; p = value * u * up;
>              draw (left--right) scaled 1 shifted p;
>              label.lft(name, p shifted 2 left);
>            enddef;
>
>            for a = 1 upto 1:
>              mark_y_axis(a, "");
>            endfor
>
>             mark_y_axis(1, "$1$");
>
>
>           vardef mark_x_axis(expr value, name) =
>             save p; pair p; p = value * u * right;
>             draw (up--down) scaled 1 shifted p;
>             label.bot(name, p shifted 2 down);
>           enddef;
>
>           for a = 1 upto 1:
>             mark_x_axis(a, "");
>           endfor
>
>           mark_x_axis(1, "$1$");
>
>
>            path rectangle;
>            rectangle = (-0.3u,-0.4u) -- (1.3u,-0.4u) -- (1.3u,-0.4u) --
> (1.3u,1.4u) -- (-0.3u,1.4u)--cycle;
>
>            clip currentpicture to rectangle;
>           \stopMPpage
>
your exp usage:

   exp(-60*-0.4)

if you see what huge numbers come out of that, like

-51.006602 11100558579.857309 l
-50.989594 11034154639.123087 l
-50.972586 10968147929.149401 l
-50.955579 10902536073.687559 l
-50.938571 10837316710.703716 l

you could imagine a viewer crapping out on that because no matter what
one clips it still is 'kind of drawn', so what viewer do you use?

Hans

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