/src/igraph/vendor/lapack/dlassq.c

Source (jump to first uncovered line)
/*  -- translated by f2c (version 20191129).
   You must link the resulting object file with libf2c:
  on Microsoft Windows system, link with libf2c.lib;
  on Linux or Unix systems, link with .../path/to/libf2c.a -lm
  or, if you install libf2c.a in a standard place, with -lf2c -lm
  -- in that order, at the end of the command line, as in
    cc *.o -lf2c -lm
  Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,

    http://www.netlib.org/f2c/libf2c.zip
*/

#include "f2c.h"

/* > \brief \b DLASSQ updates a sum of squares represented in scaled form.   

    =========== DOCUMENTATION ===========   

   Online html documentation available at   
              http://www.netlib.org/lapack/explore-html/   

   > \htmlonly   
   > Download DLASSQ + dependencies   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlassq.
f">   
   > [TGZ]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlassq.
f">   
   > [ZIP]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlassq.
f">   
   > [TXT]</a>   
   > \endhtmlonly   

    Definition:   
    ===========   

         SUBROUTINE DLASSQ( N, X, INCX, SCALE, SUMSQ )   

         INTEGER            INCX, N   
         DOUBLE PRECISION   SCALE, SUMSQ   
         DOUBLE PRECISION   X( * )   


   > \par Purpose:   
    =============   
   >   
   > \verbatim   
   >   
   > DLASSQ  returns the values  scl  and  smsq  such that   
   >   
   >    ( scl**2 )*smsq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,   
   >   
   > where  x( i ) = X( 1 + ( i - 1 )*INCX ). The value of  sumsq  is   
   > assumed to be non-negative and  scl  returns the value   
   >   
   >    scl = max( scale, abs( x( i ) ) ).   
   >   
   > scale and sumsq must be supplied in SCALE and SUMSQ and   
   > scl and smsq are overwritten on SCALE and SUMSQ respectively.   
   >   
   > The routine makes only one pass through the vector x.   
   > \endverbatim   

    Arguments:   
    ==========   

   > \param[in] N   
   > \verbatim   
   >          N is INTEGER   
   >          The number of elements to be used from the vector X.   
   > \endverbatim   
   >   
   > \param[in] X   
   > \verbatim   
   >          X is DOUBLE PRECISION array, dimension (N)   
   >          The vector for which a scaled sum of squares is computed.   
   >             x( i )  = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.   
   > \endverbatim   
   >   
   > \param[in] INCX   
   > \verbatim   
   >          INCX is INTEGER   
   >          The increment between successive values of the vector X.   
   >          INCX > 0.   
   > \endverbatim   
   >   
   > \param[in,out] SCALE   
   > \verbatim   
   >          SCALE is DOUBLE PRECISION   
   >          On entry, the value  scale  in the equation above.   
   >          On exit, SCALE is overwritten with  scl , the scaling factor   
   >          for the sum of squares.   
   > \endverbatim   
   >   
   > \param[in,out] SUMSQ   
   > \verbatim   
   >          SUMSQ is DOUBLE PRECISION   
   >          On entry, the value  sumsq  in the equation above.   
   >          On exit, SUMSQ is overwritten with  smsq , the basic sum of   
   >          squares from which  scl  has been factored out.   
   > \endverbatim   

    Authors:   
    ========   

   > \author Univ. of Tennessee   
   > \author Univ. of California Berkeley   
   > \author Univ. of Colorado Denver   
   > \author NAG Ltd.   

   > \date September 2012   

   > \ingroup auxOTHERauxiliary   

    =====================================================================   
   Subroutine */ int igraphdlassq_(integer *n, doublereal *x, integer *incx, 
  doublereal *scale, doublereal *sumsq)
{
    /* System generated locals */
    integer i__1, i__2;
    doublereal d__1;

    /* Local variables */
    integer ix;
    doublereal absxi;
    extern logical igraphdisnan_(doublereal *);


/*  -- LAPACK auxiliary routine (version 3.4.2) --   
    -- LAPACK is a software package provided by Univ. of Tennessee,    --   
    -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--   
       September 2012   


   =====================================================================   


       Parameter adjustments */
    --x;

    /* Function Body */
    if (*n > 0) {
  i__1 = (*n - 1) * *incx + 1;
  i__2 = *incx;
  for (ix = 1; i__2 < 0 ? ix >= i__1 : ix <= i__1; ix += i__2) {
      absxi = (d__1 = x[ix], abs(d__1));
      if (absxi > 0. || igraphdisnan_(&absxi)) {
    if (*scale < absxi) {
/* Computing 2nd power */
        d__1 = *scale / absxi;
        *sumsq = *sumsq * (d__1 * d__1) + 1;
        *scale = absxi;
    } else {
/* Computing 2nd power */
        d__1 = absxi / *scale;
        *sumsq += d__1 * d__1;
    }
      }
/* L10: */
  }
    }
    return 0;

/*     End of DLASSQ */

} /* igraphdlassq_ */


Line	Count	Source (jump to first uncovered line)
1		/* -- translated by f2c (version 20191129).
2		You must link the resulting object file with libf2c:
3		on Microsoft Windows system, link with libf2c.lib;
4		on Linux or Unix systems, link with .../path/to/libf2c.a -lm
5		or, if you install libf2c.a in a standard place, with -lf2c -lm
6		-- in that order, at the end of the command line, as in
7		cc *.o -lf2c -lm
8		Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
9
10		http://www.netlib.org/f2c/libf2c.zip
11		*/
12
13		#include "f2c.h"
14
15		/* > \brief \b DLASSQ updates a sum of squares represented in scaled form.
16
17		=========== DOCUMENTATION ===========
18
19		Online html documentation available at
20		http://www.netlib.org/lapack/explore-html/
21
22		> \htmlonly
23		> Download DLASSQ + dependencies
24		> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlassq.
25		f">
26		> [TGZ]</a>
27		> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlassq.
28		f">
29		> [ZIP]</a>
30		> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlassq.
31		f">
32		> [TXT]</a>
33		> \endhtmlonly
34
35		Definition:
36		===========
37
38		SUBROUTINE DLASSQ( N, X, INCX, SCALE, SUMSQ )
39
40		INTEGER INCX, N
41		DOUBLE PRECISION SCALE, SUMSQ
42		DOUBLE PRECISION X( * )
43
44
45		> \par Purpose:
46		=============
47		>
48		> \verbatim
49		>
50		> DLASSQ returns the values scl and smsq such that
51		>
52		> ( scl*2 )smsq = x( 1 )2 +...+ x( n )2 + ( scale*2 )sumsq,
53		>
54		> where x( i ) = X( 1 + ( i - 1 )*INCX ). The value of sumsq is
55		> assumed to be non-negative and scl returns the value
56		>
57		> scl = max( scale, abs( x( i ) ) ).
58		>
59		> scale and sumsq must be supplied in SCALE and SUMSQ and
60		> scl and smsq are overwritten on SCALE and SUMSQ respectively.
61		>
62		> The routine makes only one pass through the vector x.
63		> \endverbatim
64
65		Arguments:
66		==========
67
68		> \param[in] N
69		> \verbatim
70		> N is INTEGER
71		> The number of elements to be used from the vector X.
72		> \endverbatim
73		>
74		> \param[in] X
75		> \verbatim
76		> X is DOUBLE PRECISION array, dimension (N)
77		> The vector for which a scaled sum of squares is computed.
78		> x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.
79		> \endverbatim
80		>
81		> \param[in] INCX
82		> \verbatim
83		> INCX is INTEGER
84		> The increment between successive values of the vector X.
85		> INCX > 0.
86		> \endverbatim
87		>
88		> \param[in,out] SCALE
89		> \verbatim
90		> SCALE is DOUBLE PRECISION
91		> On entry, the value scale in the equation above.
92		> On exit, SCALE is overwritten with scl , the scaling factor
93		> for the sum of squares.
94		> \endverbatim
95		>
96		> \param[in,out] SUMSQ
97		> \verbatim
98		> SUMSQ is DOUBLE PRECISION
99		> On entry, the value sumsq in the equation above.
100		> On exit, SUMSQ is overwritten with smsq , the basic sum of
101		> squares from which scl has been factored out.
102		> \endverbatim
103
104		Authors:
105		========
106
107		> \author Univ. of Tennessee
108		> \author Univ. of California Berkeley
109		> \author Univ. of Colorado Denver
110		> \author NAG Ltd.
111
112		> \date September 2012
113
114		> \ingroup auxOTHERauxiliary
115
116		=====================================================================
117		Subroutine / int igraphdlassq_(integer n, doublereal x, integer incx,
118		doublereal scale, doublereal sumsq)
119	0	{
120		/* System generated locals */
121	0	integer i__1, i__2;
122	0	doublereal d__1;
123
124		/* Local variables */
125	0	integer ix;
126	0	doublereal absxi;
127	0	extern logical igraphdisnan_(doublereal *);
128
129
130		/* -- LAPACK auxiliary routine (version 3.4.2) --
131		-- LAPACK is a software package provided by Univ. of Tennessee, --
132		-- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
133		September 2012
134
135
136		=====================================================================
137
138
139		Parameter adjustments */
140	0	--x;
141
142		/* Function Body */
143	0	if (*n > 0) {
144	0	i__1 = (n - 1) *incx + 1;
145	0	i__2 = *incx;
146	0	for (ix = 1; i__2 < 0 ? ix >= i__1 : ix <= i__1; ix += i__2) {
147	0	absxi = (d__1 = x[ix], abs(d__1));
148	0	if (absxi > 0. \|\| igraphdisnan_(&absxi)) {
149	0	if (*scale < absxi) {
150		/* Computing 2nd power */
151	0	d__1 = *scale / absxi;
152	0	sumsq = sumsq * (d__1 * d__1) + 1;
153	0	*scale = absxi;
154	0	} else {
155		/* Computing 2nd power */
156	0	d__1 = absxi / *scale;
157	0	sumsq += d__1 d__1;
158	0	}
159	0	}
160		/* L10: */
161	0	}
162	0	}
163	0	return 0;
164
165		/* End of DLASSQ */
166
167	0	} /* igraphdlassq_ */
168

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Created: 2023-06-07 06:06