In this excercise we will use Minuit to fit histograms. In order to save some time we have written an IDA file that will generate a variety of histograms to be fit. The file is located in $SLD_FAC0:[SLDWWW.WORKBOOK]TESTHIST.IDA , to copy it issue:
COPY $SLD_FAC0:[SLDWWW.WORKBOOK]TESTHIST.IDA *
Now start up an ida sessions, after Ida has loaded type:
Now we must load the command processor. All command processors are loaded with the command CMDPROC (processor name) , we will be using the command processor MFITCMD. So at the IDA prompt issue the command:
Now all commands starting with MFIT will be sent to MINUIT.
We see the three basic mfit commands:
We see in addition to the above 3 there is:
Please spend a few minutes reading the help on each of these.
Ida> HOUT 1 SDDXWDO Ida> MFIT HIST 1 Ida> MFIT FUNCTION GAUSSIAN Ida> MFIT GO Ida> MFIT SHOW Ida> HOUT 1 SDDXWDOSo we see Minuit was able to fit the function. Issuing the MFIT SHOW command gives us the Chisq, NDF, Range and minimization routine as well as the resultant fit parameterrs and thier errors. Issuing the HOUT command after running the fit overlays the fit onto the original histogram.