[ROOT] What's that? pow(x, -2.2) in Log-Log-Plot...

From: Thomas Bretz (tbretz@astro.uni-wuerzburg.de)
Date: Wed Apr 24 2002 - 13:07:47 MEST 

Hi all,

I'm trying to make a very simple log-log-plot of a very very simple
function... BUT...it doesn't appear as a line... (I'm using root 3.02/07
on Linux kernel 2.4.6) I attach a plot how it looks like... It is
neither working as macro nor with Aclic. I tried also an interpreted
function
TF f("pow(x, -2.2)", ...)
this seems to work fine.

--------- macro: test.C ----------

Double_t lumifunc(Double_t *x, Double_t *k=NULL)
{
    Double_t N0=1.0;
    return pow(x[0], -2.2);
}
void test()
{
    TF1 func1("LF", lumifunc, 0.001, 1, 0);
    func1.Clone()->Draw();
    gPad->SetLogx();
    gPad->SetLogy();
}

-----------------------------------

Can I do something wrong here?

Best regards,
Thomas.
#include <TF1.h> Double_t lumifunc(Double_t *x, Double_t *k=NULL) { Double_t N0=1.0; return pow(x[0], -2.2); } /* Double_t spectrum(Double_t *x, Double_t *k=NULL) { Double_t A0=1.37e-10; Double_t alpha=-2; return A0*pow(x[0], alpha); } */ Double_t Eofz(Double_t *x, Double_t *k=NULL) { Double_t o=0.3; //Omega Double_t r=0.0; //Omega_R Double_t l=0.7; //Omega_L Double_t zplus1=x[0]+1; return 1./sqrt((o*zplus1+r)*zplus1*zplus1+l); } Double_t dl(Double_t *x, Double_t *k=NULL) { Double_t H0=65; Double_t c=2.99e-8; TF1 func1("Eofz", Eofz, 0., 6, 0); Double_t integ=func1.Integral(0, x[0], NULL); return integ*c/H0; } Double_t flux(Double_t *x, Double_t *k) { Double_t z=k[0]; Double_t beta=1.1; Double_t d=dl(&z); if(d==0) return 0; return x[0]*pow(z+1, 1.-beta) / (TMath::Pi()*4) / (d*d); } Double_t mult(Double_t *x, Double_t *k) { Double_t L = x[0]; Double_t z = k[0]; return lumifunc(&L) * flux(&L,&z); } void haupt() { TF1 func1("LF", lumifunc, 0.001, 1, 1); func1.SetParameter(0, 0.03); func1.Clone()->Draw(); gPad->SetLogx(); gPad->SetLogy(); //TF1 t("name", "LF*sp", 0.001, 1); // t.Clone()->Draw(); }

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