Coverage Report

Created: 2025-09-05 19:41

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
/root/doris/contrib/openblas/lapack-netlib/SRC/slas2.c
Line
Count
Source
1
#include <math.h>
2
#include <stdlib.h>
3
#include <string.h>
4
#include <stdio.h>
5
#include <complex.h>
6
#ifdef complex
7
#undef complex
8
#endif
9
#ifdef I
10
#undef I
11
#endif
12
13
#if defined(_WIN64)
14
typedef long long BLASLONG;
15
typedef unsigned long long BLASULONG;
16
#else
17
typedef long BLASLONG;
18
typedef unsigned long BLASULONG;
19
#endif
20
21
#ifdef LAPACK_ILP64
22
typedef BLASLONG blasint;
23
#if defined(_WIN64)
24
#define blasabs(x) llabs(x)
25
#else
26
#define blasabs(x) labs(x)
27
#endif
28
#else
29
typedef int blasint;
30
#define blasabs(x) abs(x)
31
#endif
32
33
typedef blasint integer;
34
35
typedef unsigned int uinteger;
36
typedef char *address;
37
typedef short int shortint;
38
typedef float real;
39
typedef double doublereal;
40
typedef struct { real r, i; } complex;
41
typedef struct { doublereal r, i; } doublecomplex;
42
#ifdef _MSC_VER
43
static inline _Fcomplex Cf(complex *z) {_Fcomplex zz={z->r , z->i}; return zz;}
44
static inline _Dcomplex Cd(doublecomplex *z) {_Dcomplex zz={z->r , z->i};return zz;}
45
static inline _Fcomplex * _pCf(complex *z) {return (_Fcomplex*)z;}
46
static inline _Dcomplex * _pCd(doublecomplex *z) {return (_Dcomplex*)z;}
47
#else
48
0
static inline _Complex float Cf(complex *z) {return z->r + z->i*_Complex_I;}
49
0
static inline _Complex double Cd(doublecomplex *z) {return z->r + z->i*_Complex_I;}
50
0
static inline _Complex float * _pCf(complex *z) {return (_Complex float*)z;}
51
0
static inline _Complex double * _pCd(doublecomplex *z) {return (_Complex double*)z;}
52
#endif
53
#define pCf(z) (*_pCf(z))
54
#define pCd(z) (*_pCd(z))
55
typedef blasint logical;
56
57
typedef char logical1;
58
typedef char integer1;
59
60
#define TRUE_ (1)
61
#define FALSE_ (0)
62
63
/* Extern is for use with -E */
64
#ifndef Extern
65
#define Extern extern
66
#endif
67
68
/* I/O stuff */
69
70
typedef int flag;
71
typedef int ftnlen;
72
typedef int ftnint;
73
74
/*external read, write*/
75
typedef struct
76
{ flag cierr;
77
  ftnint ciunit;
78
  flag ciend;
79
  char *cifmt;
80
  ftnint cirec;
81
} cilist;
82
83
/*internal read, write*/
84
typedef struct
85
{ flag icierr;
86
  char *iciunit;
87
  flag iciend;
88
  char *icifmt;
89
  ftnint icirlen;
90
  ftnint icirnum;
91
} icilist;
92
93
/*open*/
94
typedef struct
95
{ flag oerr;
96
  ftnint ounit;
97
  char *ofnm;
98
  ftnlen ofnmlen;
99
  char *osta;
100
  char *oacc;
101
  char *ofm;
102
  ftnint orl;
103
  char *oblnk;
104
} olist;
105
106
/*close*/
107
typedef struct
108
{ flag cerr;
109
  ftnint cunit;
110
  char *csta;
111
} cllist;
112
113
/*rewind, backspace, endfile*/
114
typedef struct
115
{ flag aerr;
116
  ftnint aunit;
117
} alist;
118
119
/* inquire */
120
typedef struct
121
{ flag inerr;
122
  ftnint inunit;
123
  char *infile;
124
  ftnlen infilen;
125
  ftnint  *inex;  /*parameters in standard's order*/
126
  ftnint  *inopen;
127
  ftnint  *innum;
128
  ftnint  *innamed;
129
  char  *inname;
130
  ftnlen  innamlen;
131
  char  *inacc;
132
  ftnlen  inacclen;
133
  char  *inseq;
134
  ftnlen  inseqlen;
135
  char  *indir;
136
  ftnlen  indirlen;
137
  char  *infmt;
138
  ftnlen  infmtlen;
139
  char  *inform;
140
  ftnint  informlen;
141
  char  *inunf;
142
  ftnlen  inunflen;
143
  ftnint  *inrecl;
144
  ftnint  *innrec;
145
  char  *inblank;
146
  ftnlen  inblanklen;
147
} inlist;
148
149
#define VOID void
150
151
union Multitype { /* for multiple entry points */
152
  integer1 g;
153
  shortint h;
154
  integer i;
155
  /* longint j; */
156
  real r;
157
  doublereal d;
158
  complex c;
159
  doublecomplex z;
160
  };
161
162
typedef union Multitype Multitype;
163
164
struct Vardesc {  /* for Namelist */
165
  char *name;
166
  char *addr;
167
  ftnlen *dims;
168
  int  type;
169
  };
170
typedef struct Vardesc Vardesc;
171
172
struct Namelist {
173
  char *name;
174
  Vardesc **vars;
175
  int nvars;
176
  };
177
typedef struct Namelist Namelist;
178
179
0
#define abs(x) ((x) >= 0 ? (x) : -(x))
180
#define dabs(x) (fabs(x))
181
0
#define f2cmin(a,b) ((a) <= (b) ? (a) : (b))
182
0
#define f2cmax(a,b) ((a) >= (b) ? (a) : (b))
183
#define dmin(a,b) (f2cmin(a,b))
184
#define dmax(a,b) (f2cmax(a,b))
185
#define bit_test(a,b) ((a) >> (b) & 1)
186
#define bit_clear(a,b)  ((a) & ~((uinteger)1 << (b)))
187
#define bit_set(a,b)  ((a) |  ((uinteger)1 << (b)))
188
189
#define abort_() { sig_die("Fortran abort routine called", 1); }
190
#define c_abs(z) (cabsf(Cf(z)))
191
#define c_cos(R,Z) { pCf(R)=ccos(Cf(Z)); }
192
#ifdef _MSC_VER
193
#define c_div(c, a, b) {Cf(c)._Val[0] = (Cf(a)._Val[0]/Cf(b)._Val[0]); Cf(c)._Val[1]=(Cf(a)._Val[1]/Cf(b)._Val[1]);}
194
#define z_div(c, a, b) {Cd(c)._Val[0] = (Cd(a)._Val[0]/Cd(b)._Val[0]); Cd(c)._Val[1]=(Cd(a)._Val[1]/df(b)._Val[1]);}
195
#else
196
#define c_div(c, a, b) {pCf(c) = Cf(a)/Cf(b);}
197
#define z_div(c, a, b) {pCd(c) = Cd(a)/Cd(b);}
198
#endif
199
#define c_exp(R, Z) {pCf(R) = cexpf(Cf(Z));}
200
#define c_log(R, Z) {pCf(R) = clogf(Cf(Z));}
201
#define c_sin(R, Z) {pCf(R) = csinf(Cf(Z));}
202
//#define c_sqrt(R, Z) {*(R) = csqrtf(Cf(Z));}
203
#define c_sqrt(R, Z) {pCf(R) = csqrtf(Cf(Z));}
204
#define d_abs(x) (fabs(*(x)))
205
#define d_acos(x) (acos(*(x)))
206
#define d_asin(x) (asin(*(x)))
207
#define d_atan(x) (atan(*(x)))
208
#define d_atn2(x, y) (atan2(*(x),*(y)))
209
#define d_cnjg(R, Z) { pCd(R) = conj(Cd(Z)); }
210
#define r_cnjg(R, Z) { pCf(R) = conjf(Cf(Z)); }
211
#define d_cos(x) (cos(*(x)))
212
#define d_cosh(x) (cosh(*(x)))
213
#define d_dim(__a, __b) ( *(__a) > *(__b) ? *(__a) - *(__b) : 0.0 )
214
#define d_exp(x) (exp(*(x)))
215
#define d_imag(z) (cimag(Cd(z)))
216
#define r_imag(z) (cimagf(Cf(z)))
217
#define d_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
218
#define r_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
219
#define d_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
220
#define r_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
221
#define d_log(x) (log(*(x)))
222
#define d_mod(x, y) (fmod(*(x), *(y)))
223
#define u_nint(__x) ((__x)>=0 ? floor((__x) + .5) : -floor(.5 - (__x)))
224
#define d_nint(x) u_nint(*(x))
225
#define u_sign(__a,__b) ((__b) >= 0 ? ((__a) >= 0 ? (__a) : -(__a)) : -((__a) >= 0 ? (__a) : -(__a)))
226
#define d_sign(a,b) u_sign(*(a),*(b))
227
#define r_sign(a,b) u_sign(*(a),*(b))
228
#define d_sin(x) (sin(*(x)))
229
#define d_sinh(x) (sinh(*(x)))
230
#define d_sqrt(x) (sqrt(*(x)))
231
#define d_tan(x) (tan(*(x)))
232
#define d_tanh(x) (tanh(*(x)))
233
#define i_abs(x) abs(*(x))
234
#define i_dnnt(x) ((integer)u_nint(*(x)))
235
#define i_len(s, n) (n)
236
#define i_nint(x) ((integer)u_nint(*(x)))
237
#define i_sign(a,b) ((integer)u_sign((integer)*(a),(integer)*(b)))
238
#define pow_dd(ap, bp) ( pow(*(ap), *(bp)))
239
#define pow_si(B,E) spow_ui(*(B),*(E))
240
#define pow_ri(B,E) spow_ui(*(B),*(E))
241
#define pow_di(B,E) dpow_ui(*(B),*(E))
242
#define pow_zi(p, a, b) {pCd(p) = zpow_ui(Cd(a), *(b));}
243
#define pow_ci(p, a, b) {pCf(p) = cpow_ui(Cf(a), *(b));}
244
#define pow_zz(R,A,B) {pCd(R) = cpow(Cd(A),*(B));}
245
#define s_cat(lpp, rpp, rnp, np, llp) {   ftnlen i, nc, ll; char *f__rp, *lp;   ll = (llp); lp = (lpp);   for(i=0; i < (int)*(np); ++i) {           nc = ll;          if((rnp)[i] < nc) nc = (rnp)[i];          ll -= nc;           f__rp = (rpp)[i];           while(--nc >= 0) *lp++ = *(f__rp)++;         }  while(--ll >= 0) *lp++ = ' '; }
246
#define s_cmp(a,b,c,d) ((integer)strncmp((a),(b),f2cmin((c),(d))))
247
#define s_copy(A,B,C,D) { int __i,__m; for (__i=0, __m=f2cmin((C),(D)); __i<__m && (B)[__i] != 0; ++__i) (A)[__i] = (B)[__i]; }
248
#define sig_die(s, kill) { exit(1); }
249
#define s_stop(s, n) {exit(0);}
250
static char junk[] = "\n@(#)LIBF77 VERSION 19990503\n";
251
#define z_abs(z) (cabs(Cd(z)))
252
#define z_exp(R, Z) {pCd(R) = cexp(Cd(Z));}
253
#define z_sqrt(R, Z) {pCd(R) = csqrt(Cd(Z));}
254
#define myexit_() break;
255
#define mycycle() continue;
256
#define myceiling(w) {ceil(w)}
257
#define myhuge(w) {HUGE_VAL}
258
//#define mymaxloc_(w,s,e,n) {if (sizeof(*(w)) == sizeof(double)) dmaxloc_((w),*(s),*(e),n); else dmaxloc_((w),*(s),*(e),n);}
259
#define mymaxloc(w,s,e,n) {dmaxloc_(w,*(s),*(e),n)}
260
261
/* procedure parameter types for -A and -C++ */
262
263
264
#ifdef __cplusplus
265
typedef logical (*L_fp)(...);
266
#else
267
typedef logical (*L_fp)();
268
#endif
269
270
0
static float spow_ui(float x, integer n) {
271
0
  float pow=1.0; unsigned long int u;
272
0
  if(n != 0) {
273
0
    if(n < 0) n = -n, x = 1/x;
274
0
    for(u = n; ; ) {
275
0
      if(u & 01) pow *= x;
276
0
      if(u >>= 1) x *= x;
277
0
      else break;
278
0
    }
279
0
  }
280
0
  return pow;
281
0
}
282
0
static double dpow_ui(double x, integer n) {
283
0
  double pow=1.0; unsigned long int u;
284
0
  if(n != 0) {
285
0
    if(n < 0) n = -n, x = 1/x;
286
0
    for(u = n; ; ) {
287
0
      if(u & 01) pow *= x;
288
0
      if(u >>= 1) x *= x;
289
0
      else break;
290
0
    }
291
0
  }
292
0
  return pow;
293
0
}
294
#ifdef _MSC_VER
295
static _Fcomplex cpow_ui(complex x, integer n) {
296
  complex pow={1.0,0.0}; unsigned long int u;
297
    if(n != 0) {
298
    if(n < 0) n = -n, x.r = 1/x.r, x.i=1/x.i;
299
    for(u = n; ; ) {
300
      if(u & 01) pow.r *= x.r, pow.i *= x.i;
301
      if(u >>= 1) x.r *= x.r, x.i *= x.i;
302
      else break;
303
    }
304
  }
305
  _Fcomplex p={pow.r, pow.i};
306
  return p;
307
}
308
#else
309
0
static _Complex float cpow_ui(_Complex float x, integer n) {
310
0
  _Complex float pow=1.0; unsigned long int u;
311
0
  if(n != 0) {
312
0
    if(n < 0) n = -n, x = 1/x;
313
0
    for(u = n; ; ) {
314
0
      if(u & 01) pow *= x;
315
0
      if(u >>= 1) x *= x;
316
0
      else break;
317
0
    }
318
0
  }
319
0
  return pow;
320
0
}
321
#endif
322
#ifdef _MSC_VER
323
static _Dcomplex zpow_ui(_Dcomplex x, integer n) {
324
  _Dcomplex pow={1.0,0.0}; unsigned long int u;
325
  if(n != 0) {
326
    if(n < 0) n = -n, x._Val[0] = 1/x._Val[0], x._Val[1] =1/x._Val[1];
327
    for(u = n; ; ) {
328
      if(u & 01) pow._Val[0] *= x._Val[0], pow._Val[1] *= x._Val[1];
329
      if(u >>= 1) x._Val[0] *= x._Val[0], x._Val[1] *= x._Val[1];
330
      else break;
331
    }
332
  }
333
  _Dcomplex p = {pow._Val[0], pow._Val[1]};
334
  return p;
335
}
336
#else
337
0
static _Complex double zpow_ui(_Complex double x, integer n) {
338
0
  _Complex double pow=1.0; unsigned long int u;
339
0
  if(n != 0) {
340
0
    if(n < 0) n = -n, x = 1/x;
341
0
    for(u = n; ; ) {
342
0
      if(u & 01) pow *= x;
343
0
      if(u >>= 1) x *= x;
344
0
      else break;
345
0
    }
346
0
  }
347
0
  return pow;
348
0
}
349
#endif
350
0
static integer pow_ii(integer x, integer n) {
351
0
  integer pow; unsigned long int u;
352
0
  if (n <= 0) {
353
0
    if (n == 0 || x == 1) pow = 1;
354
0
    else if (x != -1) pow = x == 0 ? 1/x : 0;
355
0
    else n = -n;
356
0
  }
357
0
  if ((n > 0) || !(n == 0 || x == 1 || x != -1)) {
358
0
    u = n;
359
0
    for(pow = 1; ; ) {
360
0
      if(u & 01) pow *= x;
361
0
      if(u >>= 1) x *= x;
362
0
      else break;
363
0
    }
364
0
  }
365
0
  return pow;
366
0
}
367
static integer dmaxloc_(double *w, integer s, integer e, integer *n)
368
0
{
369
0
  double m; integer i, mi;
370
0
  for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
371
0
    if (w[i-1]>m) mi=i ,m=w[i-1];
372
0
  return mi-s+1;
373
0
}
374
static integer smaxloc_(float *w, integer s, integer e, integer *n)
375
0
{
376
0
  float m; integer i, mi;
377
0
  for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
378
0
    if (w[i-1]>m) mi=i ,m=w[i-1];
379
0
  return mi-s+1;
380
0
}
381
0
static inline void cdotc_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
382
0
  integer n = *n_, incx = *incx_, incy = *incy_, i;
383
0
#ifdef _MSC_VER
384
0
  _Fcomplex zdotc = {0.0, 0.0};
385
0
  if (incx == 1 && incy == 1) {
386
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
387
0
      zdotc._Val[0] += conjf(Cf(&x[i]))._Val[0] * Cf(&y[i])._Val[0];
388
0
      zdotc._Val[1] += conjf(Cf(&x[i]))._Val[1] * Cf(&y[i])._Val[1];
389
0
    }
390
0
  } else {
391
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
392
0
      zdotc._Val[0] += conjf(Cf(&x[i*incx]))._Val[0] * Cf(&y[i*incy])._Val[0];
393
0
      zdotc._Val[1] += conjf(Cf(&x[i*incx]))._Val[1] * Cf(&y[i*incy])._Val[1];
394
0
    }
395
0
  }
396
0
  pCf(z) = zdotc;
397
0
}
398
0
#else
399
0
  _Complex float zdotc = 0.0;
400
0
  if (incx == 1 && incy == 1) {
401
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
402
0
      zdotc += conjf(Cf(&x[i])) * Cf(&y[i]);
403
0
    }
404
0
  } else {
405
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
406
0
      zdotc += conjf(Cf(&x[i*incx])) * Cf(&y[i*incy]);
407
0
    }
408
0
  }
409
0
  pCf(z) = zdotc;
410
0
}
411
#endif
412
0
static inline void zdotc_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
413
0
  integer n = *n_, incx = *incx_, incy = *incy_, i;
414
0
#ifdef _MSC_VER
415
0
  _Dcomplex zdotc = {0.0, 0.0};
416
0
  if (incx == 1 && incy == 1) {
417
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
418
0
      zdotc._Val[0] += conj(Cd(&x[i]))._Val[0] * Cd(&y[i])._Val[0];
419
0
      zdotc._Val[1] += conj(Cd(&x[i]))._Val[1] * Cd(&y[i])._Val[1];
420
0
    }
421
0
  } else {
422
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
423
0
      zdotc._Val[0] += conj(Cd(&x[i*incx]))._Val[0] * Cd(&y[i*incy])._Val[0];
424
0
      zdotc._Val[1] += conj(Cd(&x[i*incx]))._Val[1] * Cd(&y[i*incy])._Val[1];
425
0
    }
426
0
  }
427
0
  pCd(z) = zdotc;
428
0
}
429
0
#else
430
0
  _Complex double zdotc = 0.0;
431
0
  if (incx == 1 && incy == 1) {
432
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
433
0
      zdotc += conj(Cd(&x[i])) * Cd(&y[i]);
434
0
    }
435
0
  } else {
436
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
437
0
      zdotc += conj(Cd(&x[i*incx])) * Cd(&y[i*incy]);
438
0
    }
439
0
  }
440
0
  pCd(z) = zdotc;
441
0
}
442
#endif  
443
0
static inline void cdotu_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
444
0
  integer n = *n_, incx = *incx_, incy = *incy_, i;
445
0
#ifdef _MSC_VER
446
0
  _Fcomplex zdotc = {0.0, 0.0};
447
0
  if (incx == 1 && incy == 1) {
448
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
449
0
      zdotc._Val[0] += Cf(&x[i])._Val[0] * Cf(&y[i])._Val[0];
450
0
      zdotc._Val[1] += Cf(&x[i])._Val[1] * Cf(&y[i])._Val[1];
451
0
    }
452
0
  } else {
453
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
454
0
      zdotc._Val[0] += Cf(&x[i*incx])._Val[0] * Cf(&y[i*incy])._Val[0];
455
0
      zdotc._Val[1] += Cf(&x[i*incx])._Val[1] * Cf(&y[i*incy])._Val[1];
456
0
    }
457
0
  }
458
0
  pCf(z) = zdotc;
459
0
}
460
0
#else
461
0
  _Complex float zdotc = 0.0;
462
0
  if (incx == 1 && incy == 1) {
463
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
464
0
      zdotc += Cf(&x[i]) * Cf(&y[i]);
465
0
    }
466
0
  } else {
467
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
468
0
      zdotc += Cf(&x[i*incx]) * Cf(&y[i*incy]);
469
0
    }
470
0
  }
471
0
  pCf(z) = zdotc;
472
0
}
473
#endif
474
0
static inline void zdotu_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
475
0
  integer n = *n_, incx = *incx_, incy = *incy_, i;
476
0
#ifdef _MSC_VER
477
0
  _Dcomplex zdotc = {0.0, 0.0};
478
0
  if (incx == 1 && incy == 1) {
479
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
480
0
      zdotc._Val[0] += Cd(&x[i])._Val[0] * Cd(&y[i])._Val[0];
481
0
      zdotc._Val[1] += Cd(&x[i])._Val[1] * Cd(&y[i])._Val[1];
482
0
    }
483
0
  } else {
484
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
485
0
      zdotc._Val[0] += Cd(&x[i*incx])._Val[0] * Cd(&y[i*incy])._Val[0];
486
0
      zdotc._Val[1] += Cd(&x[i*incx])._Val[1] * Cd(&y[i*incy])._Val[1];
487
0
    }
488
0
  }
489
0
  pCd(z) = zdotc;
490
0
}
491
0
#else
492
0
  _Complex double zdotc = 0.0;
493
0
  if (incx == 1 && incy == 1) {
494
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
495
0
      zdotc += Cd(&x[i]) * Cd(&y[i]);
496
0
    }
497
0
  } else {
498
0
    for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
499
0
      zdotc += Cd(&x[i*incx]) * Cd(&y[i*incy]);
500
0
    }
501
0
  }
502
0
  pCd(z) = zdotc;
503
0
}
504
#endif
505
/*  -- translated by f2c (version 20000121).
506
   You must link the resulting object file with the libraries:
507
  -lf2c -lm   (in that order)
508
*/
509
510
511
512
513
/* > \brief \b SLAS2 computes singular values of a 2-by-2 triangular matrix. */
514
515
/*  =========== DOCUMENTATION =========== */
516
517
/* Online html documentation available at */
518
/*            http://www.netlib.org/lapack/explore-html/ */
519
520
/* > \htmlonly */
521
/* > Download SLAS2 + dependencies */
522
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slas2.f
523
"> */
524
/* > [TGZ]</a> */
525
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slas2.f
526
"> */
527
/* > [ZIP]</a> */
528
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slas2.f
529
"> */
530
/* > [TXT]</a> */
531
/* > \endhtmlonly */
532
533
/*  Definition: */
534
/*  =========== */
535
536
/*       SUBROUTINE SLAS2( F, G, H, SSMIN, SSMAX ) */
537
538
/*       REAL               F, G, H, SSMAX, SSMIN */
539
540
541
/* > \par Purpose: */
542
/*  ============= */
543
/* > */
544
/* > \verbatim */
545
/* > */
546
/* > SLAS2  computes the singular values of the 2-by-2 matrix */
547
/* >    [  F   G  ] */
548
/* >    [  0   H  ]. */
549
/* > On return, SSMIN is the smaller singular value and SSMAX is the */
550
/* > larger singular value. */
551
/* > \endverbatim */
552
553
/*  Arguments: */
554
/*  ========== */
555
556
/* > \param[in] F */
557
/* > \verbatim */
558
/* >          F is REAL */
559
/* >          The (1,1) element of the 2-by-2 matrix. */
560
/* > \endverbatim */
561
/* > */
562
/* > \param[in] G */
563
/* > \verbatim */
564
/* >          G is REAL */
565
/* >          The (1,2) element of the 2-by-2 matrix. */
566
/* > \endverbatim */
567
/* > */
568
/* > \param[in] H */
569
/* > \verbatim */
570
/* >          H is REAL */
571
/* >          The (2,2) element of the 2-by-2 matrix. */
572
/* > \endverbatim */
573
/* > */
574
/* > \param[out] SSMIN */
575
/* > \verbatim */
576
/* >          SSMIN is REAL */
577
/* >          The smaller singular value. */
578
/* > \endverbatim */
579
/* > */
580
/* > \param[out] SSMAX */
581
/* > \verbatim */
582
/* >          SSMAX is REAL */
583
/* >          The larger singular value. */
584
/* > \endverbatim */
585
586
/*  Authors: */
587
/*  ======== */
588
589
/* > \author Univ. of Tennessee */
590
/* > \author Univ. of California Berkeley */
591
/* > \author Univ. of Colorado Denver */
592
/* > \author NAG Ltd. */
593
594
/* > \date December 2016 */
595
596
/* > \ingroup OTHERauxiliary */
597
598
/* > \par Further Details: */
599
/*  ===================== */
600
/* > */
601
/* > \verbatim */
602
/* > */
603
/* >  Barring over/underflow, all output quantities are correct to within */
604
/* >  a few units in the last place (ulps), even in the absence of a guard */
605
/* >  digit in addition/subtraction. */
606
/* > */
607
/* >  In IEEE arithmetic, the code works correctly if one matrix element is */
608
/* >  infinite. */
609
/* > */
610
/* >  Overflow will not occur unless the largest singular value itself */
611
/* >  overflows, or is within a few ulps of overflow. (On machines with */
612
/* >  partial overflow, like the Cray, overflow may occur if the largest */
613
/* >  singular value is within a factor of 2 of overflow.) */
614
/* > */
615
/* >  Underflow is harmless if underflow is gradual. Otherwise, results */
616
/* >  may correspond to a matrix modified by perturbations of size near */
617
/* >  the underflow threshold. */
618
/* > \endverbatim */
619
/* > */
620
/*  ===================================================================== */
621
/* Subroutine */ void slas2_(real *f, real *g, real *h__, real *ssmin, real *
622
  ssmax)
623
0
{
624
    /* System generated locals */
625
0
    real r__1, r__2;
626
627
    /* Local variables */
628
0
    real fhmn, fhmx, c__, fa, ga, ha, as, at, au;
629
630
631
/*  -- LAPACK auxiliary routine (version 3.7.0) -- */
632
/*  -- LAPACK is a software package provided by Univ. of Tennessee,    -- */
633
/*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
634
/*     December 2016 */
635
636
637
/*  ==================================================================== */
638
639
640
0
    fa = abs(*f);
641
0
    ga = abs(*g);
642
0
    ha = abs(*h__);
643
0
    fhmn = f2cmin(fa,ha);
644
0
    fhmx = f2cmax(fa,ha);
645
0
    if (fhmn == 0.f) {
646
0
  *ssmin = 0.f;
647
0
  if (fhmx == 0.f) {
648
0
      *ssmax = ga;
649
0
  } else {
650
/* Computing 2nd power */
651
0
      r__1 = f2cmin(fhmx,ga) / f2cmax(fhmx,ga);
652
0
      *ssmax = f2cmax(fhmx,ga) * sqrt(r__1 * r__1 + 1.f);
653
0
  }
654
0
    } else {
655
0
  if (ga < fhmx) {
656
0
      as = fhmn / fhmx + 1.f;
657
0
      at = (fhmx - fhmn) / fhmx;
658
/* Computing 2nd power */
659
0
      r__1 = ga / fhmx;
660
0
      au = r__1 * r__1;
661
0
      c__ = 2.f / (sqrt(as * as + au) + sqrt(at * at + au));
662
0
      *ssmin = fhmn * c__;
663
0
      *ssmax = fhmx / c__;
664
0
  } else {
665
0
      au = fhmx / ga;
666
0
      if (au == 0.f) {
667
668
/*              Avoid possible harmful underflow if exponent range */
669
/*              asymmetric (true SSMIN may not underflow even if */
670
/*              AU underflows) */
671
672
0
    *ssmin = fhmn * fhmx / ga;
673
0
    *ssmax = ga;
674
0
      } else {
675
0
    as = fhmn / fhmx + 1.f;
676
0
    at = (fhmx - fhmn) / fhmx;
677
/* Computing 2nd power */
678
0
    r__1 = as * au;
679
/* Computing 2nd power */
680
0
    r__2 = at * au;
681
0
    c__ = 1.f / (sqrt(r__1 * r__1 + 1.f) + sqrt(r__2 * r__2 + 1.f)
682
0
      );
683
0
    *ssmin = fhmn * c__ * au;
684
0
    *ssmin += *ssmin;
685
0
    *ssmax = ga / (c__ + c__);
686
0
      }
687
0
  }
688
0
    }
689
0
    return;
690
691
/*     End of SLAS2 */
692
693
0
} /* slas2_ */
694