24-28 june 2002ACAT'021 Toolkit for partonic process data storage and manipulation  Reasons and ideas of the toolkit  New standard of partonic events storage  Toolkit utilities  Current status of the toolkit development Balatenichev S., Cherstnev A., Ilyin V. (SINP MSU)

24-28 june 2002ACAT'022 Why do we need this toolkit? I.Modern complexity of MC generation has resulted in separation of 2 stages of the generation: ME (e.g. CompHEP) and SH (e.g. PYTHIA) II. Many collaborations have and develop databases of Monte-Carlo events at hard partonic level. Since MC generation in many cases is heavy task, changes of the data is faster to do by direct operations with the events without re-generation. One needs interface between these stages Toolkit of utilities for these manipulation

24-28 june 2002ACAT'023 Structure of the toolkit Data manipulation (mixing, updating, cuts and etc.) Partonic events database SH (PYTHIA) ME (CompHEP) Visualization (Root)

24-28 june 2002ACAT'024 New data storage standard Text file format is optimal for partonic events storage, in our opinion. Thus, a some standardization is needed for these files. The standard we proposed gives flexibility for data description and manipulations. Specific points for this standard are: A physical information from ME to SH is highly heterogeneous. Our standard allows to transfer different types of the information within uniform syntax. We assume that SH generator or a manipulation utility will take that information transferred which can interpret.

24-28 june 2002ACAT'025 New data storage standard Header of the file Text file of partonic events Description of physical information: beams, processes, etc. Event 1 Event 2 … Partonic event records

24-28 june 2002ACAT'026 Header Syntax Basic unit of information in the header – command Syntax: command name = command value Command value can be of numerical type or string (in that case it encloses in quotes). Some commands can be grouped under tags. Tag syntax: ##Tag name: command 1,…, command N,; 1.Double # – the beginning of the tag 2. semicolon – the end of the tag The header information is stored as a set of tags. The tags are separated from event records by extra semicolon.

24-28 june 2002ACAT'027 ##generator: name=‘CompHEP’, version=‘4.2.00’,; ##beam: energy=1.000E+03, KF=2212, name=‘proton', mass=9.380E-01,; ##strfun: name='CTEQ', version='5m1', PDFid=833, PDFgr=11, PDFfile=‘$PDF/cteq5m1.pdf',; ##process: ID=1, name='u D -> E1 n1 b B ', CrosSec= E-02, CrosSecErr= E-03, Nparton=6, master=3,; ##n_event: IDprocess=1, N=1000, multN=1, maxW= E+00,; ##parton: IDprocess=1, in=1, KF=2, name='u', mass= E+00,; ##parton: IDprocess=1, out=2, KF=11, name=‘n1', mass= E+00,; ##total: Nprocess=1, CrosSec= E-02, CrosSecErr= E-03, Nevent=1000,; ##QCDprocess: IDprocess=1, NL=2, Qnorm= E+01, QCDalpha= E-01, file_name='$GEN/c_source/num/alpha_s.c', func_name='alpha_c(int q)',;; Example of the tags set

24-28 june 2002ACAT'028 Event record Event record occupies one line in the data file. 1. For the interpretation of event records we introduce special tag: ##format: IDprocess=5, ProcNumber='i', p1.3='13.6E', p2.3='13.6E', p3.1='13.6E', p3.2='13.6E', p3.3='13.6E', p4.1='13.6E', p4.2='13.6E', p4.3=‘13.6E', Q='10.3E', color_chain=‘string’,; 2. event record consists of statements divided with colons. Event record example: 1: E+02: E+02: E+01: E+00: E+01: E+01: E+01: E+01:9.119E+01:(1 2)(6 5)

24-28 june 2002ACAT'029 Advantages of the standard 1.Our text file standard corresponds to Les Houches generic format for events storage in FORTRAN common blocks (hep/ph ). 2. Immediate advantages are: Independence of programming languages for ME and SH generators. readability Simple realization.

24-28 june 2002ACAT'0210 Connection to Les Houches format We re-write FORTRAN Les Houches common blocks to C structures. Example is: #define maxproc 100 typedef struct procinfo { int id_beam[2]; /* KF of beam particle */ double ebmup[2]; /* Beam energy */ int pdf_group[2], pdf_set[2]; /* PDF information */ int master, n_proc, proc_list; /* Master switch, number of subp double cs[maxproc], cs_err[maxproc], cs_max[maxproc ] /* Cross sec int list_prc[maxproc], max_weight[maxproc]; /* Extra info } procinfo; Toolkit writer(reader) writes(reads) data to(from) datafile from(to) these structures or FORTRAN common blocks.

24-28 june 2002ACAT'0211 Toolkit utilities Storage of partonic events data in text files of this standard allows to manipulate easily with the data. We suppose that the toolkit will include utilities: Mixing and de-mixing in practice, we generate several files with partonic events and would like to mix them to one event flow and visa versa. Apply kinematical cuts phenomenological tasks require to apply kinematical cuts on events. Storage of data in our format allows to develop a utility for cut applying.

24-28 june 2002ACAT'0212 Toolkit utilities Event visualization we intend to make some utilities for remote visualization of process information and histogamming of events and etc. Updating this utility will allow to re-weigh events by MC algorithm. If distribution of new events weights is sufficiently “smooth” function, not very large part of the events statistic will be lost. For instance, this utility is convenient for updating of structure functions. Rewriter of old events files this utility rewrites events generated by CompHEP of old versions into new standard.

24-28 june 2002ACAT'0213 Current status of toolkit At present the toolkit is in test stage. We have developed: Reader and writer to Les Houches common blocks (C structures) on C and FORTRAN Mixing utility CompHEP 4.2 outputs data in the standard My supposition: the toolkit will be in site In next some months.