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mnddot.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 /* ddot.f -- translated by f2c (version 20010320).
11  You must link the resulting object file with the libraries:
12  -lf2c -lm (in that order)
13 */
14 
15 namespace ROOT {
16 
17  namespace Minuit2 {
18 
19 
20 double mnddot(unsigned int n, const double* dx, int incx, const double* dy,
21  int incy) {
22  /* System generated locals */
23  int i__1;
24  double ret_val;
25 
26  /* Local variables */
27  int i__, m;
28  double dtemp;
29  int ix, iy, mp1;
30 
31 
32  /* forms the dot product of two vectors. */
33  /* uses unrolled loops for increments equal to one. */
34  /* jack dongarra, linpack, 3/11/78. */
35  /* modified 12/3/93, array(1) declarations changed to array(*) */
36 
37 
38  /* Parameter adjustments */
39  --dy;
40  --dx;
41 
42  /* Function Body */
43  ret_val = 0.;
44  dtemp = 0.;
45  if (n <= 0) {
46  return ret_val;
47  }
48  if (incx == 1 && incy == 1) {
49  goto L20;
50  }
51 
52  /* code for unequal increments or equal increments */
53  /* not equal to 1 */
54 
55  ix = 1;
56  iy = 1;
57  if (incx < 0) {
58  ix = (-static_cast<int>(n) + 1) * incx + 1;
59  }
60  if (incy < 0) {
61  iy = (-static_cast<int>(n) + 1) * incy + 1;
62  }
63  i__1 = n;
64  for (i__ = 1; i__ <= i__1; ++i__) {
65  dtemp += dx[ix] * dy[iy];
66  ix += incx;
67  iy += incy;
68  /* L10: */
69  }
70  ret_val = dtemp;
71  return ret_val;
72 
73  /* code for both increments equal to 1 */
74 
75 
76  /* clean-up loop */
77 
78 L20:
79  m = n % 5;
80  if (m == 0) {
81  goto L40;
82  }
83  i__1 = m;
84  for (i__ = 1; i__ <= i__1; ++i__) {
85  dtemp += dx[i__] * dy[i__];
86  /* L30: */
87  }
88  if (n < 5) {
89  goto L60;
90  }
91 L40:
92  mp1 = m + 1;
93  i__1 = n;
94  for (i__ = mp1; i__ <= i__1; i__ += 5) {
95  dtemp = dtemp + dx[i__] * dy[i__] + dx[i__ + 1] * dy[i__ + 1] + dx[
96  i__ + 2] * dy[i__ + 2] + dx[i__ + 3] * dy[i__ + 3] + dx[i__ +
97  4] * dy[i__ + 4];
98  /* L50: */
99  }
100 L60:
101  ret_val = dtemp;
102  return ret_val;
103 } /* ddot_ */
104 
105 
106  } // namespace Minuit2
107 
108 } // namespace ROOT
m
auto * m
Definition: textangle.C:8
n
const Int_t n
Definition: legend1.C:16
ROOT::Minuit2::mnddot
double mnddot(unsigned int, const double *, int, const double *, int)
Definition: mnddot.cxx:28
ROOT
VSD Structures.
Definition: StringConv.hxx:21