Hi Isi,
By default, TF1::Paint computes the function at 100 equidistant points
to draw it. In your particular case, this is clearly not enough.
Set the number of points to a higher value (see in your code below).
Rene Brun
Isard_Dunietz wrote:
>
> I am confused about TF1 fncts. I want to plot out the fnct:
> f(x) = 0.7 * 0.4 * sin( 1.0 + 0.01 - par * x )
> For par = 29.6, I expect about 100 oscillations of the sin fnct when
> x ranges over 0 < x < 20.
>
> However when I code it via
>
> {
> gROOT -> Reset();
>
> TF1 avgFnct(
> "avgFnctName","0.7 * 0.4 * sin( 1.01 - [0] * x )", 0.0, 20.0
> );
>
> avgFnct.SetParName(0,"theParameter");
> avgFnct.SetParameter(0, 29.6);
avgFnct.SetNpx(2000); //< add this line
> avgFnct.Draw();
> }
>
> I get only about 6 oscillations.
> I am using version v2_24_04bKCC_3_3 of root.
>
> What silly mistake am I overlooking?
>
> Thank you, Isi Dunietz
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