ROOT   Reference Guide
mnbins.cxx
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1// @(#)root/minuit2:$Id$
2// Authors: M. Winkler, F. James, L. Moneta, A. Zsenei 2003-2005
3
4/**********************************************************************
5 * *
6 * Copyright (c) 2005 LCG ROOT Math team, CERN/PH-SFT *
7 * *
8 **********************************************************************/
9
10#include <math.h>
11
12namespace ROOT {
13
14 namespace Minuit2 {
15
16
17void mnbins(double a1, double a2, int naa, double& bl, double& bh, int& nb, double& bwid) {
18
19//*-*-*-*-*-*-*-*-*-*-*Compute reasonable histogram intervals*-*-*-*-*-*-*-*-*
20//*-* ======================================
21//*-* Function TO DETERMINE REASONABLE HISTOGRAM INTERVALS
22//*-* GIVEN ABSOLUTE UPPER AND LOWER BOUNDS A1 AND A2
23//*-* AND DESIRED MAXIMUM NUMBER OF BINS NAA
24//*-* PROGRAM MAKES REASONABLE BINNING FROM BL TO BH OF WIDTH BWID
25//*-* F. JAMES, AUGUST, 1974 , stolen for Minuit, 1988
26//*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
27
28 /* Local variables */
29 double awid,ah, al, sigfig, sigrnd, alb;
30 int kwid, lwid, na=0, log_;
31
32 al = a1 < a2 ? a1 : a2;
33 // al = std::min(a1,a2);
34 // ah = std::max(a1,a2);
35 ah = a1 > a2 ? a1 : a2;
36 if (al == ah) ah = al + 1;
37
38 //*-*- IF NAA .EQ. -1 , PROGRAM USES BWID INPUT FROM CALLING ROUTINE
39 if (naa == -1) goto L150;
40L10:
41 na = naa - 1;
42 if (na < 1) na = 1;
43
44 //*-*- GET NOMINAL BIN WIDTH IN EXPON FORM
45L20:
46 awid = (ah-al) / double(na);
47 log_ = int(log10(awid));
48 if (awid <= 1) --log_;
49 sigfig = awid*pow(10.0, -log_);
50 //*-*- ROUND MANTISSA UP TO 2, 2.5, 5, OR 10
51 if (sigfig > 2) goto L40;
52 sigrnd = 2;
53 goto L100;
54L40:
55 if (sigfig > 2.5) goto L50;
56 sigrnd = 2.5;
57 goto L100;
58L50:
59 if (sigfig > 5) goto L60;
60 sigrnd = 5;
61 goto L100;
62L60:
63 sigrnd = 1;
64 ++log_;
65L100:
66 bwid = sigrnd*pow(10.0, log_);
67 goto L200;
68 //*-*- GET NEW BOUNDS FROM NEW WIDTH BWID
69L150:
70 if (bwid <= 0) goto L10;
71L200:
72 alb = al / bwid;
73 lwid = int(alb);
74 if (alb < 0) --lwid;
75 bl = bwid*double(lwid);
76 alb = ah / bwid + 1;
77 kwid = int(alb);
78 if (alb < 0) --kwid;
79 bh = bwid*double(kwid);
80 nb = kwid - lwid;
81 if (naa > 5) goto L240;
82 if (naa == -1) return;
83 //*-*- REQUEST FOR ONE BIN IS DIFFICULT CASE
84 if (naa > 1 || nb == 1) return;
85 bwid *= 2;
86 nb = 1;
87 return;
88L240:
89 if (nb << 1 != naa) return;
90 ++na;
91 goto L20;
92} /* mnbins_ */
93
94 } // namespace Minuit2
95
96} // namespace ROOT
double
Definition: Converters.cxx:921
double pow(double, double)
double log10(double)
void mnbins(double a1, double a2, int naa, double &bl, double &bh, int &nb, double &bwid)
Definition: mnbins.cxx:17
tbb::task_arena is an alias of tbb::interface7::task_arena, which doesn't allow to forward declare tb...
Definition: StringConv.hxx:21