1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
|
/* ../netlib/clangt.f -- translated by f2c (version 20100827). 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 "FLA_f2c.h" /* Table of constant values */
static integer c__1 = 1;
/* > \brief \b CLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix. */
/* =========== DOCUMENTATION =========== */
/* Online html documentation available at */
/* http://www.netlib.org/lapack/explore-html/ */
/* > \htmlonly */
/* > Download CLANGT + dependencies */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clangt. f"> */
/* > [TGZ]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clangt. f"> */
/* > [ZIP]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clangt. f"> */
/* > [TXT]</a> */
/* > \endhtmlonly */
/* Definition: */
/* =========== */
/* REAL FUNCTION CLANGT( NORM, N, DL, D, DU ) */
/* .. Scalar Arguments .. */
/* CHARACTER NORM */
/* INTEGER N */
/* .. */
/* .. Array Arguments .. */
/* COMPLEX D( * ), DL( * ), DU( * ) */
/* .. */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > CLANGT returns the value of the one norm, or the Frobenius norm, or */
/* > the infinity norm, or the element of largest absolute value of a */
/* > complex tridiagonal matrix A. */
/* > \endverbatim */
/* > */
/* > \return CLANGT */
/* > \verbatim */
/* > */
/* > CLANGT = ( max(f2c_abs(A(i,j))), NORM = 'M' or 'm' */
/* > ( */
/* > ( norm1(A), NORM = '1', 'O' or 'o' */
/* > ( */
/* > ( normI(A), NORM = 'I' or 'i' */
/* > ( */
/* > ( normF(A), NORM = 'F', 'f', 'E' or 'e' */
/* > */
/* > where norm1 denotes the one norm of a matrix (maximum column sum), */
/* > normI denotes the infinity norm of a matrix (maximum row sum) and */
/* > normF denotes the Frobenius norm of a matrix (square root of sum of */
/* > squares). Note that max(f2c_abs(A(i,j))) is not a consistent matrix norm. */
/* > \endverbatim */
/* Arguments: */
/* ========== */
/* > \param[in] NORM */
/* > \verbatim */
/* > NORM is CHARACTER*1 */
/* > Specifies the value to be returned in CLANGT as described */
/* > above. */
/* > \endverbatim */
/* > */
/* > \param[in] N */
/* > \verbatim */
/* > N is INTEGER */
/* > The order of the matrix A. N >= 0. When N = 0, CLANGT is */
/* > set to zero. */
/* > \endverbatim */
/* > */
/* > \param[in] DL */
/* > \verbatim */
/* > DL is COMPLEX array, dimension (N-1) */
/* > The (n-1) sub-diagonal elements of A. */
/* > \endverbatim */
/* > */
/* > \param[in] D */
/* > \verbatim */
/* > D is COMPLEX array, dimension (N) */
/* > The diagonal elements of A. */
/* > \endverbatim */
/* > */
/* > \param[in] DU */
/* > \verbatim */
/* > DU is COMPLEX array, dimension (N-1) */
/* > The (n-1) super-diagonal elements of A. */
/* > \endverbatim */
/* Authors: */
/* ======== */
/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */
/* > \date September 2012 */
/* > \ingroup complexOTHERauxiliary */
/* ===================================================================== */
real clangt_(char *norm, integer *n, complex *dl, complex *d__, complex *du)
{
/* System generated locals */
integer i__1;
real ret_val, r__1;
/* Builtin functions */
double c_abs(complex *), sqrt(doublereal);
/* Local variables */
integer i__;
real sum, temp, scale;
extern logical lsame_(char *, char *);
real anorm;
extern /* Subroutine */
int classq_(integer *, complex *, integer *, real *, real *);
extern logical sisnan_(real *);
/* -- 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 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--du;
--d__;
--dl;
/* Function Body */
if (*n <= 0)
{
anorm = 0.f;
}
else if (lsame_(norm, "M"))
{
/* Find max(f2c_abs(A(i,j))). */
anorm = c_abs(&d__[*n]);
i__1 = *n - 1;
for (i__ = 1;
i__ <= i__1;
++i__)
{
r__1 = c_abs(&dl[i__]);
if (anorm < c_abs(&dl[i__]) || sisnan_(&r__1))
{
anorm = c_abs(&dl[i__]);
}
r__1 = c_abs(&d__[i__]);
if (anorm < c_abs(&d__[i__]) || sisnan_(&r__1))
{
anorm = c_abs(&d__[i__]);
}
r__1 = c_abs(&du[i__]);
if (anorm < c_abs(&du[i__]) || sisnan_(&r__1))
{
anorm = c_abs(&du[i__]);
}
/* L10: */
}
}
else if (lsame_(norm, "O") || *(unsigned char *) norm == '1')
{
/* Find norm1(A). */
if (*n == 1)
{
anorm = c_abs(&d__[1]);
}
else
{
anorm = c_abs(&d__[1]) + c_abs(&dl[1]);
temp = c_abs(&d__[*n]) + c_abs(&du[*n - 1]);
if (anorm < temp || sisnan_(&temp))
{
anorm = temp;
}
i__1 = *n - 1;
for (i__ = 2;
i__ <= i__1;
++i__)
{
temp = c_abs(&d__[i__]) + c_abs(&dl[i__]) + c_abs(&du[i__ - 1] );
if (anorm < temp || sisnan_(&temp))
{
anorm = temp;
}
/* L20: */
}
}
}
else if (lsame_(norm, "I"))
{
/* Find normI(A). */
if (*n == 1)
{
anorm = c_abs(&d__[1]);
}
else
{
anorm = c_abs(&d__[1]) + c_abs(&du[1]);
temp = c_abs(&d__[*n]) + c_abs(&dl[*n - 1]);
if (anorm < temp || sisnan_(&temp))
{
anorm = temp;
}
i__1 = *n - 1;
for (i__ = 2;
i__ <= i__1;
++i__)
{
temp = c_abs(&d__[i__]) + c_abs(&du[i__]) + c_abs(&dl[i__ - 1] );
if (anorm < temp || sisnan_(&temp))
{
anorm = temp;
}
/* L30: */
}
}
}
else if (lsame_(norm, "F") || lsame_(norm, "E"))
{
/* Find normF(A). */
scale = 0.f;
sum = 1.f;
classq_(n, &d__[1], &c__1, &scale, &sum);
if (*n > 1)
{
i__1 = *n - 1;
classq_(&i__1, &dl[1], &c__1, &scale, &sum);
i__1 = *n - 1;
classq_(&i__1, &du[1], &c__1, &scale, &sum);
}
anorm = scale * sqrt(sum);
}
ret_val = anorm;
return ret_val;
/* End of CLANGT */
}
/* clangt_ */
|
