Minuit commands: "mnexcm" arguments

ROOT
1

Hello Rooters.
I would like to understand the meaning of some of the parameters that enter the command line here below (it belongs to a macro that I am using):

Double_t arglist[10];
arglist[0] = 10000;
arglist[1] = 1;
gMinuit->mnexcm(“MIGRAD”, arglist , 2 ,ierflg);

If I look at the documentation relative to the root implementation of Minuit, I find the following:

void mnexcm(const char* comand, Double_t* plist, Int_t llist, Int_t& ierflg)

I don’t find any explanation about “plist” and “llist” and I need to understand what they do.
Can anybody help me on this? Thanks a lot in advance.

Martino

1 Like
2

Several functions in Minuit use a similar interface.
-The first argument is the type of command to execute
-plist is a pointer to an array of length >= llist containing the parameters to execute the command
-The last argument is the return code

Rene

3

thank you, Rene.
So, in my case “arglist” is a vector with 10 components. I have initialized only the first one and the second one. Components from 3 to 9 in that vector have not been initialized.
How do I know about the meaning of those components? I mean, what does the 0th component do? and what about the 1st one?

Martino

4

To see the list of all options in an interactive session, do:

root > TMinuit m; root > m.mnhelp("*") root > m.mnhelp("MIGrad")
see also: root.cern.ch/root/html/src/TMinu … html#h_OGX

Rene