Error in <TFormula::Eval>: Formula is invalid and not ready to execute

[Nea]

Hello. I want to use roofit. But my code doesn’t work.

Here is Error code.

Error in <TFormula::Eval>: Formula is invalid and not ready to execute
re is unknown.
me is unknown.
section1 is unknown.
section2 is unknown.

And this is my code.

			RooRealVar t("t", "t", 1, 4500);
			RooRealVar pi("pi", "pi", 3.14159);
			RooRealVar hn("hn", "hn", 662000.);//ev
			RooRealVar re("re", "re", 0.00000000000000281794);//unknown
			RooRealVar me("me", "me", 511000.);//ev //unknown
			RooFormulaVar s("s", "t/662000", RooArgList(t));
			RooFormulaVar ga("ga", "hn/me", RooArgList(hn,me));
			
			TF1* section1 = new TF1("f", "s*s/ga/ga/(1-s)/(1-s)", 0, 4500); //unknown
			TF1* section2 = new TF1("f", "s/(1-s)*(s-2/ga)",0,4500); //unknown
			TF1* section = new TF1("f", "pi * re * re * / me / (section1 + section2 + 2)", 0, 4500);
			RooAbsPdf* rf = bindPdf(section, x);
			rf->fitTo(*hist1);
		rf->plotOn(frame, LineColor(kYellow));

Thank you for your help.

Regards.

Nea

[RENATO_QUAGLIANI]

In

TF1* section = new TF1("f", "pi * re * re * / me / (section1 + section2 + 2)", 0, 4500);

You seem to have a bad math * / operation.

Generally speaking i don’t use the bindPdf functions ( see tutorial ROOT: tutorials/roofit/rf105_funcbinding.C Source File )
But the
RooGenericPdf class , which can be supplied direclty with

RooGenericPdf myPdf("pdf","pdf", "( @0 + @1 / @3 ....)", RooArgList( var0, var1, var2...)

Cheers

[RENATO_QUAGLIANI]

Given t is inside s

    RooRealVar t("t", "t", 1, 4500);
    RooRealVar pi("pi", "pi", 3.14159);
    RooRealVar hn("hn", "hn", 662000.);//ev
    RooRealVar re("re", "re", 0.00000000000000281794);//unknown
    RooRealVar me("me", "me", 511000.);//ev //unknown
    RooFormulaVar s("s", "@0/662000", RooArgList(t));
    RooFormulaVar ga("ga", "@0/@1", RooArgList(hn,me));
    RooGenericPdf pdf("function", "function", "3.14159 * @0*@0/(@1 *( (@2*@2)/((@3*@3)*(1-@2)*(1-@2)) + (@2*@2-2)/(@3*(1-@2)) + 2))", RooArgList( re, me, s, ga));

with this the pdf is valid, but check out the math

[Nea]

Thank you! My code works.