OpenBLAS/lapack-netlib/SRC/slatrs3.c

1263 lines
38 KiB
C

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <complex.h>
#ifdef complex
#undef complex
#endif
#ifdef I
#undef I
#endif
#if defined(_WIN64)
typedef long long BLASLONG;
typedef unsigned long long BLASULONG;
#else
typedef long BLASLONG;
typedef unsigned long BLASULONG;
#endif
#ifdef LAPACK_ILP64
typedef BLASLONG blasint;
#if defined(_WIN64)
#define blasabs(x) llabs(x)
#else
#define blasabs(x) labs(x)
#endif
#else
typedef int blasint;
#define blasabs(x) abs(x)
#endif
typedef blasint integer;
typedef unsigned int uinteger;
typedef char *address;
typedef short int shortint;
typedef float real;
typedef double doublereal;
typedef struct { real r, i; } complex;
typedef struct { doublereal r, i; } doublecomplex;
#ifdef _MSC_VER
static inline _Fcomplex Cf(complex *z) {_Fcomplex zz={z->r , z->i}; return zz;}
static inline _Dcomplex Cd(doublecomplex *z) {_Dcomplex zz={z->r , z->i};return zz;}
static inline _Fcomplex * _pCf(complex *z) {return (_Fcomplex*)z;}
static inline _Dcomplex * _pCd(doublecomplex *z) {return (_Dcomplex*)z;}
#else
static inline _Complex float Cf(complex *z) {return z->r + z->i*_Complex_I;}
static inline _Complex double Cd(doublecomplex *z) {return z->r + z->i*_Complex_I;}
static inline _Complex float * _pCf(complex *z) {return (_Complex float*)z;}
static inline _Complex double * _pCd(doublecomplex *z) {return (_Complex double*)z;}
#endif
#define pCf(z) (*_pCf(z))
#define pCd(z) (*_pCd(z))
typedef blasint logical;
typedef char logical1;
typedef char integer1;
#define TRUE_ (1)
#define FALSE_ (0)
/* Extern is for use with -E */
#ifndef Extern
#define Extern extern
#endif
/* I/O stuff */
typedef int flag;
typedef int ftnlen;
typedef int ftnint;
/*external read, write*/
typedef struct
{ flag cierr;
ftnint ciunit;
flag ciend;
char *cifmt;
ftnint cirec;
} cilist;
/*internal read, write*/
typedef struct
{ flag icierr;
char *iciunit;
flag iciend;
char *icifmt;
ftnint icirlen;
ftnint icirnum;
} icilist;
/*open*/
typedef struct
{ flag oerr;
ftnint ounit;
char *ofnm;
ftnlen ofnmlen;
char *osta;
char *oacc;
char *ofm;
ftnint orl;
char *oblnk;
} olist;
/*close*/
typedef struct
{ flag cerr;
ftnint cunit;
char *csta;
} cllist;
/*rewind, backspace, endfile*/
typedef struct
{ flag aerr;
ftnint aunit;
} alist;
/* inquire */
typedef struct
{ flag inerr;
ftnint inunit;
char *infile;
ftnlen infilen;
ftnint *inex; /*parameters in standard's order*/
ftnint *inopen;
ftnint *innum;
ftnint *innamed;
char *inname;
ftnlen innamlen;
char *inacc;
ftnlen inacclen;
char *inseq;
ftnlen inseqlen;
char *indir;
ftnlen indirlen;
char *infmt;
ftnlen infmtlen;
char *inform;
ftnint informlen;
char *inunf;
ftnlen inunflen;
ftnint *inrecl;
ftnint *innrec;
char *inblank;
ftnlen inblanklen;
} inlist;
#define VOID void
union Multitype { /* for multiple entry points */
integer1 g;
shortint h;
integer i;
/* longint j; */
real r;
doublereal d;
complex c;
doublecomplex z;
};
typedef union Multitype Multitype;
struct Vardesc { /* for Namelist */
char *name;
char *addr;
ftnlen *dims;
int type;
};
typedef struct Vardesc Vardesc;
struct Namelist {
char *name;
Vardesc **vars;
int nvars;
};
typedef struct Namelist Namelist;
#define abs(x) ((x) >= 0 ? (x) : -(x))
#define dabs(x) (fabs(x))
#define f2cmin(a,b) ((a) <= (b) ? (a) : (b))
#define f2cmax(a,b) ((a) >= (b) ? (a) : (b))
#define dmin(a,b) (f2cmin(a,b))
#define dmax(a,b) (f2cmax(a,b))
#define bit_test(a,b) ((a) >> (b) & 1)
#define bit_clear(a,b) ((a) & ~((uinteger)1 << (b)))
#define bit_set(a,b) ((a) | ((uinteger)1 << (b)))
#define abort_() { sig_die("Fortran abort routine called", 1); }
#define c_abs(z) (cabsf(Cf(z)))
#define c_cos(R,Z) { pCf(R)=ccos(Cf(Z)); }
#ifdef _MSC_VER
#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]);}
#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]/Cd(b)._Val[1]);}
#else
#define c_div(c, a, b) {pCf(c) = Cf(a)/Cf(b);}
#define z_div(c, a, b) {pCd(c) = Cd(a)/Cd(b);}
#endif
#define c_exp(R, Z) {pCf(R) = cexpf(Cf(Z));}
#define c_log(R, Z) {pCf(R) = clogf(Cf(Z));}
#define c_sin(R, Z) {pCf(R) = csinf(Cf(Z));}
//#define c_sqrt(R, Z) {*(R) = csqrtf(Cf(Z));}
#define c_sqrt(R, Z) {pCf(R) = csqrtf(Cf(Z));}
#define d_abs(x) (fabs(*(x)))
#define d_acos(x) (acos(*(x)))
#define d_asin(x) (asin(*(x)))
#define d_atan(x) (atan(*(x)))
#define d_atn2(x, y) (atan2(*(x),*(y)))
#define d_cnjg(R, Z) { pCd(R) = conj(Cd(Z)); }
#define r_cnjg(R, Z) { pCf(R) = conjf(Cf(Z)); }
#define d_cos(x) (cos(*(x)))
#define d_cosh(x) (cosh(*(x)))
#define d_dim(__a, __b) ( *(__a) > *(__b) ? *(__a) - *(__b) : 0.0 )
#define d_exp(x) (exp(*(x)))
#define d_imag(z) (cimag(Cd(z)))
#define r_imag(z) (cimagf(Cf(z)))
#define d_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
#define r_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
#define d_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
#define r_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
#define d_log(x) (log(*(x)))
#define d_mod(x, y) (fmod(*(x), *(y)))
#define u_nint(__x) ((__x)>=0 ? floor((__x) + .5) : -floor(.5 - (__x)))
#define d_nint(x) u_nint(*(x))
#define u_sign(__a,__b) ((__b) >= 0 ? ((__a) >= 0 ? (__a) : -(__a)) : -((__a) >= 0 ? (__a) : -(__a)))
#define d_sign(a,b) u_sign(*(a),*(b))
#define r_sign(a,b) u_sign(*(a),*(b))
#define d_sin(x) (sin(*(x)))
#define d_sinh(x) (sinh(*(x)))
#define d_sqrt(x) (sqrt(*(x)))
#define d_tan(x) (tan(*(x)))
#define d_tanh(x) (tanh(*(x)))
#define i_abs(x) abs(*(x))
#define i_dnnt(x) ((integer)u_nint(*(x)))
#define i_len(s, n) (n)
#define i_nint(x) ((integer)u_nint(*(x)))
#define i_sign(a,b) ((integer)u_sign((integer)*(a),(integer)*(b)))
#define pow_dd(ap, bp) ( pow(*(ap), *(bp)))
#define pow_si(B,E) spow_ui(*(B),*(E))
#define pow_ri(B,E) spow_ui(*(B),*(E))
#define pow_di(B,E) dpow_ui(*(B),*(E))
#define pow_zi(p, a, b) {pCd(p) = zpow_ui(Cd(a), *(b));}
#define pow_ci(p, a, b) {pCf(p) = cpow_ui(Cf(a), *(b));}
#define pow_zz(R,A,B) {pCd(R) = cpow(Cd(A),*(B));}
#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++ = ' '; }
#define s_cmp(a,b,c,d) ((integer)strncmp((a),(b),f2cmin((c),(d))))
#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]; }
#define sig_die(s, kill) { exit(1); }
#define s_stop(s, n) {exit(0);}
static char junk[] = "\n@(#)LIBF77 VERSION 19990503\n";
#define z_abs(z) (cabs(Cd(z)))
#define z_exp(R, Z) {pCd(R) = cexp(Cd(Z));}
#define z_sqrt(R, Z) {pCd(R) = csqrt(Cd(Z));}
#define myexit_() break;
#define mycycle_() continue;
#define myceiling_(w) {ceil(w)}
#define myhuge_(w) {HUGE_VAL}
//#define mymaxloc_(w,s,e,n) {if (sizeof(*(w)) == sizeof(double)) dmaxloc_((w),*(s),*(e),n); else dmaxloc_((w),*(s),*(e),n);}
#define mymaxloc_(w,s,e,n) dmaxloc_(w,*(s),*(e),n)
#define myexp_(w) my_expfunc(w)
static int my_expfunc(float *x) {int e; (void)frexpf(*x,&e); return e;}
/* procedure parameter types for -A and -C++ */
#ifdef __cplusplus
typedef logical (*L_fp)(...);
#else
typedef logical (*L_fp)();
#endif
static float spow_ui(float x, integer n) {
float pow=1.0; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x = 1/x;
for(u = n; ; ) {
if(u & 01) pow *= x;
if(u >>= 1) x *= x;
else break;
}
}
return pow;
}
static double dpow_ui(double x, integer n) {
double pow=1.0; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x = 1/x;
for(u = n; ; ) {
if(u & 01) pow *= x;
if(u >>= 1) x *= x;
else break;
}
}
return pow;
}
#ifdef _MSC_VER
static _Fcomplex cpow_ui(complex x, integer n) {
complex pow={1.0,0.0}; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x.r = 1/x.r, x.i=1/x.i;
for(u = n; ; ) {
if(u & 01) pow.r *= x.r, pow.i *= x.i;
if(u >>= 1) x.r *= x.r, x.i *= x.i;
else break;
}
}
_Fcomplex p={pow.r, pow.i};
return p;
}
#else
static _Complex float cpow_ui(_Complex float x, integer n) {
_Complex float pow=1.0; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x = 1/x;
for(u = n; ; ) {
if(u & 01) pow *= x;
if(u >>= 1) x *= x;
else break;
}
}
return pow;
}
#endif
#ifdef _MSC_VER
static _Dcomplex zpow_ui(_Dcomplex x, integer n) {
_Dcomplex pow={1.0,0.0}; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x._Val[0] = 1/x._Val[0], x._Val[1] =1/x._Val[1];
for(u = n; ; ) {
if(u & 01) pow._Val[0] *= x._Val[0], pow._Val[1] *= x._Val[1];
if(u >>= 1) x._Val[0] *= x._Val[0], x._Val[1] *= x._Val[1];
else break;
}
}
_Dcomplex p = {pow._Val[0], pow._Val[1]};
return p;
}
#else
static _Complex double zpow_ui(_Complex double x, integer n) {
_Complex double pow=1.0; unsigned long int u;
if(n != 0) {
if(n < 0) n = -n, x = 1/x;
for(u = n; ; ) {
if(u & 01) pow *= x;
if(u >>= 1) x *= x;
else break;
}
}
return pow;
}
#endif
static integer pow_ii(integer x, integer n) {
integer pow; unsigned long int u;
if (n <= 0) {
if (n == 0 || x == 1) pow = 1;
else if (x != -1) pow = x == 0 ? 1/x : 0;
else n = -n;
}
if ((n > 0) || !(n == 0 || x == 1 || x != -1)) {
u = n;
for(pow = 1; ; ) {
if(u & 01) pow *= x;
if(u >>= 1) x *= x;
else break;
}
}
return pow;
}
static integer dmaxloc_(double *w, integer s, integer e, integer *n)
{
double m; integer i, mi;
for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
if (w[i-1]>m) mi=i ,m=w[i-1];
return mi-s+1;
}
static integer smaxloc_(float *w, integer s, integer e, integer *n)
{
float m; integer i, mi;
for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
if (w[i-1]>m) mi=i ,m=w[i-1];
return mi-s+1;
}
static inline void cdotc_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
integer n = *n_, incx = *incx_, incy = *incy_, i;
#ifdef _MSC_VER
_Fcomplex zdotc = {0.0, 0.0};
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += conjf(Cf(&x[i]))._Val[0] * Cf(&y[i])._Val[0];
zdotc._Val[1] += conjf(Cf(&x[i]))._Val[1] * Cf(&y[i])._Val[1];
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += conjf(Cf(&x[i*incx]))._Val[0] * Cf(&y[i*incy])._Val[0];
zdotc._Val[1] += conjf(Cf(&x[i*incx]))._Val[1] * Cf(&y[i*incy])._Val[1];
}
}
pCf(z) = zdotc;
}
#else
_Complex float zdotc = 0.0;
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += conjf(Cf(&x[i])) * Cf(&y[i]);
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += conjf(Cf(&x[i*incx])) * Cf(&y[i*incy]);
}
}
pCf(z) = zdotc;
}
#endif
static inline void zdotc_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
integer n = *n_, incx = *incx_, incy = *incy_, i;
#ifdef _MSC_VER
_Dcomplex zdotc = {0.0, 0.0};
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += conj(Cd(&x[i]))._Val[0] * Cd(&y[i])._Val[0];
zdotc._Val[1] += conj(Cd(&x[i]))._Val[1] * Cd(&y[i])._Val[1];
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += conj(Cd(&x[i*incx]))._Val[0] * Cd(&y[i*incy])._Val[0];
zdotc._Val[1] += conj(Cd(&x[i*incx]))._Val[1] * Cd(&y[i*incy])._Val[1];
}
}
pCd(z) = zdotc;
}
#else
_Complex double zdotc = 0.0;
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += conj(Cd(&x[i])) * Cd(&y[i]);
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += conj(Cd(&x[i*incx])) * Cd(&y[i*incy]);
}
}
pCd(z) = zdotc;
}
#endif
static inline void cdotu_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
integer n = *n_, incx = *incx_, incy = *incy_, i;
#ifdef _MSC_VER
_Fcomplex zdotc = {0.0, 0.0};
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += Cf(&x[i])._Val[0] * Cf(&y[i])._Val[0];
zdotc._Val[1] += Cf(&x[i])._Val[1] * Cf(&y[i])._Val[1];
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += Cf(&x[i*incx])._Val[0] * Cf(&y[i*incy])._Val[0];
zdotc._Val[1] += Cf(&x[i*incx])._Val[1] * Cf(&y[i*incy])._Val[1];
}
}
pCf(z) = zdotc;
}
#else
_Complex float zdotc = 0.0;
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += Cf(&x[i]) * Cf(&y[i]);
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += Cf(&x[i*incx]) * Cf(&y[i*incy]);
}
}
pCf(z) = zdotc;
}
#endif
static inline void zdotu_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
integer n = *n_, incx = *incx_, incy = *incy_, i;
#ifdef _MSC_VER
_Dcomplex zdotc = {0.0, 0.0};
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += Cd(&x[i])._Val[0] * Cd(&y[i])._Val[0];
zdotc._Val[1] += Cd(&x[i])._Val[1] * Cd(&y[i])._Val[1];
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc._Val[0] += Cd(&x[i*incx])._Val[0] * Cd(&y[i*incy])._Val[0];
zdotc._Val[1] += Cd(&x[i*incx])._Val[1] * Cd(&y[i*incy])._Val[1];
}
}
pCd(z) = zdotc;
}
#else
_Complex double zdotc = 0.0;
if (incx == 1 && incy == 1) {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += Cd(&x[i]) * Cd(&y[i]);
}
} else {
for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
zdotc += Cd(&x[i*incx]) * Cd(&y[i*incy]);
}
}
pCd(z) = zdotc;
}
#endif
/* -- translated by f2c (version 20000121).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
/* Table of constant values */
static integer c__1 = 1;
static integer c_n1 = -1;
static real c_b35 = -1.f;
static real c_b36 = 1.f;
/* > \brief \b SLATRS3 solves a triangular system of equations with the scale factors set to prevent overflow.
*/
/* Definition: */
/* =========== */
/* SUBROUTINE SLATRS3( UPLO, TRANS, DIAG, NORMIN, N, NRHS, A, LDA, */
/* X, LDX, SCALE, CNORM, WORK, LWORK, INFO ) */
/* CHARACTER DIAG, NORMIN, TRANS, UPLO */
/* INTEGER INFO, LDA, LWORK, LDX, N, NRHS */
/* REAL A( LDA, * ), CNORM( * ), SCALE( * ), */
/* WORK( * ), X( LDX, * ) */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > SLATRS3 solves one of the triangular systems */
/* > */
/* > A * X = B * diag(scale) or A**T * X = B * diag(scale) */
/* > */
/* > with scaling to prevent overflow. Here A is an upper or lower */
/* > triangular matrix, A**T denotes the transpose of A. X and B are */
/* > n by nrhs matrices and scale is an nrhs element vector of scaling */
/* > factors. A scaling factor scale(j) is usually less than or equal */
/* > to 1, chosen such that X(:,j) is less than the overflow threshold. */
/* > If the matrix A is singular (A(j,j) = 0 for some j), then */
/* > a non-trivial solution to A*X = 0 is returned. If the system is */
/* > so badly scaled that the solution cannot be represented as */
/* > (1/scale(k))*X(:,k), then x(:,k) = 0 and scale(k) is returned. */
/* > */
/* > This is a BLAS-3 version of LATRS for solving several right */
/* > hand sides simultaneously. */
/* > */
/* > \endverbatim */
/* Arguments: */
/* ========== */
/* > \param[in] UPLO */
/* > \verbatim */
/* > UPLO is CHARACTER*1 */
/* > Specifies whether the matrix A is upper or lower triangular. */
/* > = 'U': Upper triangular */
/* > = 'L': Lower triangular */
/* > \endverbatim */
/* > */
/* > \param[in] TRANS */
/* > \verbatim */
/* > TRANS is CHARACTER*1 */
/* > Specifies the operation applied to A. */
/* > = 'N': Solve A * x = s*b (No transpose) */
/* > = 'T': Solve A**T* x = s*b (Transpose) */
/* > = 'C': Solve A**T* x = s*b (Conjugate transpose = Transpose) */
/* > \endverbatim */
/* > */
/* > \param[in] DIAG */
/* > \verbatim */
/* > DIAG is CHARACTER*1 */
/* > Specifies whether or not the matrix A is unit triangular. */
/* > = 'N': Non-unit triangular */
/* > = 'U': Unit triangular */
/* > \endverbatim */
/* > */
/* > \param[in] NORMIN */
/* > \verbatim */
/* > NORMIN is CHARACTER*1 */
/* > Specifies whether CNORM has been set or not. */
/* > = 'Y': CNORM contains the column norms on entry */
/* > = 'N': CNORM is not set on entry. On exit, the norms will */
/* > be computed and stored in CNORM. */
/* > \endverbatim */
/* > */
/* > \param[in] N */
/* > \verbatim */
/* > N is INTEGER */
/* > The order of the matrix A. N >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in] NRHS */
/* > \verbatim */
/* > NRHS is INTEGER */
/* > The number of columns of X. NRHS >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in] A */
/* > \verbatim */
/* > A is REAL array, dimension (LDA,N) */
/* > The triangular matrix A. If UPLO = 'U', the leading n by n */
/* > upper triangular part of the array A contains the upper */
/* > triangular matrix, and the strictly lower triangular part of */
/* > A is not referenced. If UPLO = 'L', the leading n by n lower */
/* > triangular part of the array A contains the lower triangular */
/* > matrix, and the strictly upper triangular part of A is not */
/* > referenced. If DIAG = 'U', the diagonal elements of A are */
/* > also not referenced and are assumed to be 1. */
/* > \endverbatim */
/* > */
/* > \param[in] LDA */
/* > \verbatim */
/* > LDA is INTEGER */
/* > The leading dimension of the array A. LDA >= f2cmax (1,N). */
/* > \endverbatim */
/* > */
/* > \param[in,out] X */
/* > \verbatim */
/* > X is REAL array, dimension (LDX,NRHS) */
/* > On entry, the right hand side B of the triangular system. */
/* > On exit, X is overwritten by the solution matrix X. */
/* > \endverbatim */
/* > */
/* > \param[in] LDX */
/* > \verbatim */
/* > LDX is INTEGER */
/* > The leading dimension of the array X. LDX >= f2cmax (1,N). */
/* > \endverbatim */
/* > */
/* > \param[out] SCALE */
/* > \verbatim */
/* > SCALE is REAL array, dimension (NRHS) */
/* > The scaling factor s(k) is for the triangular system */
/* > A * x(:,k) = s(k)*b(:,k) or A**T* x(:,k) = s(k)*b(:,k). */
/* > If SCALE = 0, the matrix A is singular or badly scaled. */
/* > If A(j,j) = 0 is encountered, a non-trivial vector x(:,k) */
/* > that is an exact or approximate solution to A*x(:,k) = 0 */
/* > is returned. If the system so badly scaled that solution */
/* > cannot be presented as x(:,k) * 1/s(k), then x(:,k) = 0 */
/* > is returned. */
/* > \endverbatim */
/* > */
/* > \param[in,out] CNORM */
/* > \verbatim */
/* > CNORM is REAL array, dimension (N) */
/* > */
/* > If NORMIN = 'Y', CNORM is an input argument and CNORM(j) */
/* > contains the norm of the off-diagonal part of the j-th column */
/* > of A. If TRANS = 'N', CNORM(j) must be greater than or equal */
/* > to the infinity-norm, and if TRANS = 'T' or 'C', CNORM(j) */
/* > must be greater than or equal to the 1-norm. */
/* > */
/* > If NORMIN = 'N', CNORM is an output argument and CNORM(j) */
/* > returns the 1-norm of the offdiagonal part of the j-th column */
/* > of A. */
/* > \endverbatim */
/* > */
/* > \param[out] WORK */
/* > \verbatim */
/* > WORK is REAL array, dimension (LWORK). */
/* > On exit, if INFO = 0, WORK(1) returns the optimal size of */
/* > WORK. */
/* > \endverbatim */
/* > */
/* > \param[in] LWORK */
/* > LWORK is INTEGER */
/* > LWORK >= MAX(1, 2*NBA * MAX(NBA, MIN(NRHS, 32)), where */
/* > NBA = (N + NB - 1)/NB and NB is the optimal block size. */
/* > */
/* > If LWORK = -1, then a workspace query is assumed; the routine */
/* > only calculates the optimal dimensions of the WORK array, returns */
/* > this value as the first entry of the WORK array, and no error */
/* > message related to LWORK is issued by XERBLA. */
/* > */
/* > \param[out] INFO */
/* > \verbatim */
/* > INFO is INTEGER */
/* > = 0: successful exit */
/* > < 0: if INFO = -k, the k-th argument had an illegal value */
/* > \endverbatim */
/* Authors: */
/* ======== */
/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */
/* > \ingroup doubleOTHERauxiliary */
/* > \par Further Details: */
/* ===================== */
/* \verbatim */
/* The algorithm follows the structure of a block triangular solve. */
/* The diagonal block is solved with a call to the robust the triangular */
/* solver LATRS for every right-hand side RHS = 1, ..., NRHS */
/* op(A( J, J )) * x( J, RHS ) = SCALOC * b( J, RHS ), */
/* where op( A ) = A or op( A ) = A**T. */
/* The linear block updates operate on block columns of X, */
/* B( I, K ) - op(A( I, J )) * X( J, K ) */
/* and use GEMM. To avoid overflow in the linear block update, the worst case */
/* growth is estimated. For every RHS, a scale factor s <= 1.0 is computed */
/* such that */
/* || s * B( I, RHS )||_oo */
/* + || op(A( I, J )) ||_oo * || s * X( J, RHS ) ||_oo <= Overflow threshold */
/* Once all columns of a block column have been rescaled (BLAS-1), the linear */
/* update is executed with GEMM without overflow. */
/* To limit rescaling, local scale factors track the scaling of column segments. */
/* There is one local scale factor s( I, RHS ) per block row I = 1, ..., NBA */
/* per right-hand side column RHS = 1, ..., NRHS. The global scale factor */
/* SCALE( RHS ) is chosen as the smallest local scale factor s( I, RHS ) */
/* I = 1, ..., NBA. */
/* A triangular solve op(A( J, J )) * x( J, RHS ) = SCALOC * b( J, RHS ) */
/* updates the local scale factor s( J, RHS ) := s( J, RHS ) * SCALOC. The */
/* linear update of potentially inconsistently scaled vector segments */
/* s( I, RHS ) * b( I, RHS ) - op(A( I, J )) * ( s( J, RHS )* x( J, RHS ) ) */
/* computes a consistent scaling SCAMIN = MIN( s(I, RHS ), s(J, RHS) ) and, */
/* if necessary, rescales the blocks prior to calling GEMM. */
/* \endverbatim */
/* ===================================================================== */
/* References: */
/* C. C. Kjelgaard Mikkelsen, A. B. Schwarz and L. Karlsson (2019). */
/* Parallel robust solution of triangular linear systems. Concurrency */
/* and Computation: Practice and Experience, 31(19), e5064. */
/* Contributor: */
/* Angelika Schwarz, Umea University, Sweden. */
/* ===================================================================== */
/* Subroutine */ void slatrs3_(char *uplo, char *trans, char *diag, char *
normin, integer *n, integer *nrhs, real *a, integer *lda, real *x,
integer *ldx, real *scale, real *cnorm, real *work, integer *lwork,
integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, x_dim1, x_offset, i__1, i__2, i__3, i__4, i__5,
i__6, i__7, i__8;
real r__1, r__2;
/* Local variables */
integer iinc, jinc;
real scal, anrm, bnrm;
integer awrk;
real tmax, xnrm[32];
integer i__, j, k;
real w[64];
extern logical lsame_(char *, char *);
real rscal;
extern /* Subroutine */ void sscal_(integer *, real *, real *, integer *),
sgemm_(char *, char *, integer *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *);
integer lanrm, ilast, jlast, i1;
logical upper;
integer i2, j1, j2, k1, k2, nb, ii, kk, lscale;
real scaloc;
extern real slamch_(char *), slange_(char *, integer *, integer *,
real *, integer *, real *);
real scamin;
extern /* Subroutine */ int xerbla_(char *, integer *, ftnlen );
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *, ftnlen, ftnlen);
real bignum;
extern real slarmm_(real *, real *, real *);
integer ifirst;
logical notran;
integer jfirst;
extern /* Subroutine */ void slatrs_(char *, char *, char *, char *,
integer *, real *, integer *, real *, real *, real *, integer *);
real smlnum;
logical nounit, lquery;
integer nba, lds, nbx, rhs;
/* ===================================================================== */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1 * 1;
a -= a_offset;
x_dim1 = *ldx;
x_offset = 1 + x_dim1 * 1;
x -= x_offset;
--scale;
--cnorm;
--work;
/* Function Body */
*info = 0;
upper = lsame_(uplo, "U");
notran = lsame_(trans, "N");
nounit = lsame_(diag, "N");
lquery = *lwork == -1;
/* Partition A and X into blocks. */
/* Computing MAX */
i__1 = 8, i__2 = ilaenv_(&c__1, "SLATRS", "", n, n, &c_n1, &c_n1, (ftnlen)
6, (ftnlen)0);
nb = f2cmax(i__1,i__2);
nb = f2cmin(64,nb);
/* Computing MAX */
i__1 = 1, i__2 = (*n + nb - 1) / nb;
nba = f2cmax(i__1,i__2);
/* Computing MAX */
i__1 = 1, i__2 = (*nrhs + 31) / 32;
nbx = f2cmax(i__1,i__2);
/* Compute the workspace */
/* The workspace comprises two parts. */
/* The first part stores the local scale factors. Each simultaneously */
/* computed right-hand side requires one local scale factor per block */
/* row. WORK( I + KK * LDS ) is the scale factor of the vector */
/* segment associated with the I-th block row and the KK-th vector */
/* in the block column. */
/* Computing MAX */
i__1 = nba, i__2 = f2cmin(*nrhs,32);
lscale = nba * f2cmax(i__1,i__2);
lds = nba;
/* The second part stores upper bounds of the triangular A. There are */
/* a total of NBA x NBA blocks, of which only the upper triangular */
/* part or the lower triangular part is referenced. The upper bound of */
/* the block A( I, J ) is stored as WORK( AWRK + I + J * NBA ). */
lanrm = nba * nba;
awrk = lscale;
work[1] = (real) (lscale + lanrm);
/* Test the input parameters. */
if (! upper && ! lsame_(uplo, "L")) {
*info = -1;
} else if (! notran && ! lsame_(trans, "T") && !
lsame_(trans, "C")) {
*info = -2;
} else if (! nounit && ! lsame_(diag, "U")) {
*info = -3;
} else if (! lsame_(normin, "Y") && ! lsame_(normin,
"N")) {
*info = -4;
} else if (*n < 0) {
*info = -5;
} else if (*nrhs < 0) {
*info = -6;
} else if (*lda < f2cmax(1,*n)) {
*info = -8;
} else if (*ldx < f2cmax(1,*n)) {
*info = -10;
} else if (! lquery && (real) (*lwork) < work[1]) {
*info = -14;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SLATRS3", &i__1, 7);
return;
} else if (lquery) {
return;
}
/* Initialize scaling factors */
i__1 = *nrhs;
for (kk = 1; kk <= i__1; ++kk) {
scale[kk] = 1.f;
}
/* Quick return if possible */
if (f2cmin(*n,*nrhs) == 0) {
return;
}
/* Determine machine dependent constant to control overflow. */
bignum = slamch_("Overflow");
smlnum = slamch_("Safe Minimum");
/* Use unblocked code for small problems */
if (*nrhs < 2) {
slatrs_(uplo, trans, diag, normin, n, &a[a_offset], lda, &x[x_dim1 +
1], &scale[1], &cnorm[1], info);
i__1 = *nrhs;
for (k = 2; k <= i__1; ++k) {
slatrs_(uplo, trans, diag, "Y", n, &a[a_offset], lda, &x[k *
x_dim1 + 1], &scale[k], &cnorm[1], info);
}
return;
}
/* Compute norms of blocks of A excluding diagonal blocks and find */
/* the block with the largest norm TMAX. */
tmax = 0.f;
i__1 = nba;
for (j = 1; j <= i__1; ++j) {
j1 = (j - 1) * nb + 1;
/* Computing MIN */
i__2 = j * nb;
j2 = f2cmin(i__2,*n) + 1;
if (upper) {
ifirst = 1;
ilast = j - 1;
} else {
ifirst = j + 1;
ilast = nba;
}
i__2 = ilast;
for (i__ = ifirst; i__ <= i__2; ++i__) {
i1 = (i__ - 1) * nb + 1;
/* Computing MIN */
i__3 = i__ * nb;
i2 = f2cmin(i__3,*n) + 1;
/* Compute upper bound of A( I1:I2-1, J1:J2-1 ). */
if (notran) {
i__3 = i2 - i1;
i__4 = j2 - j1;
anrm = slange_("I", &i__3, &i__4, &a[i1 + j1 * a_dim1], lda,
w);
work[awrk + i__ + (j - 1) * nba] = anrm;
} else {
i__3 = i2 - i1;
i__4 = j2 - j1;
anrm = slange_("1", &i__3, &i__4, &a[i1 + j1 * a_dim1], lda,
w);
work[awrk + j + (i__ - 1) * nba] = anrm;
}
tmax = f2cmax(tmax,anrm);
}
}
if (! (tmax <= slamch_("Overflow"))) {
/* Some matrix entries have huge absolute value. At least one upper */
/* bound norm( A(I1:I2-1, J1:J2-1), 'I') is not a valid floating-point */
/* number, either due to overflow in LANGE or due to Inf in A. */
/* Fall back to LATRS. Set normin = 'N' for every right-hand side to */
/* force computation of TSCAL in LATRS to avoid the likely overflow */
/* in the computation of the column norms CNORM. */
i__1 = *nrhs;
for (k = 1; k <= i__1; ++k) {
slatrs_(uplo, trans, diag, "N", n, &a[a_offset], lda, &x[k *
x_dim1 + 1], &scale[k], &cnorm[1], info);
}
return;
}
/* Every right-hand side requires workspace to store NBA local scale */
/* factors. To save workspace, X is computed successively in block columns */
/* of width NBRHS, requiring a total of NBA x NBRHS space. If sufficient */
/* workspace is available, larger values of NBRHS or NBRHS = NRHS are viable. */
i__1 = nbx;
for (k = 1; k <= i__1; ++k) {
/* Loop over block columns (index = K) of X and, for column-wise scalings, */
/* over individual columns (index = KK). */
/* K1: column index of the first column in X( J, K ) */
/* K2: column index of the first column in X( J, K+1 ) */
/* so the K2 - K1 is the column count of the block X( J, K ) */
k1 = (k - 1 << 5) + 1;
/* Computing MIN */
i__2 = k << 5;
k2 = f2cmin(i__2,*nrhs) + 1;
/* Initialize local scaling factors of current block column X( J, K ) */
i__2 = k2 - k1;
for (kk = 1; kk <= i__2; ++kk) {
i__3 = nba;
for (i__ = 1; i__ <= i__3; ++i__) {
work[i__ + kk * lds] = 1.f;
}
}
if (notran) {
/* Solve A * X(:, K1:K2-1) = B * diag(scale(K1:K2-1)) */
if (upper) {
jfirst = nba;
jlast = 1;
jinc = -1;
} else {
jfirst = 1;
jlast = nba;
jinc = 1;
}
} else {
/* Solve A**T * X(:, K1:K2-1) = B * diag(scale(K1:K2-1)) */
if (upper) {
jfirst = 1;
jlast = nba;
jinc = 1;
} else {
jfirst = nba;
jlast = 1;
jinc = -1;
}
}
i__2 = jlast;
i__3 = jinc;
for (j = jfirst; i__3 < 0 ? j >= i__2 : j <= i__2; j += i__3) {
/* J1: row index of the first row in A( J, J ) */
/* J2: row index of the first row in A( J+1, J+1 ) */
/* so that J2 - J1 is the row count of the block A( J, J ) */
j1 = (j - 1) * nb + 1;
/* Computing MIN */
i__4 = j * nb;
j2 = f2cmin(i__4,*n) + 1;
/* Solve op(A( J, J )) * X( J, RHS ) = SCALOC * B( J, RHS ) */
/* for all right-hand sides in the current block column, */
/* one RHS at a time. */
i__4 = k2 - k1;
for (kk = 1; kk <= i__4; ++kk) {
rhs = k1 + kk - 1;
if (kk == 1) {
i__5 = j2 - j1;
slatrs_(uplo, trans, diag, "N", &i__5, &a[j1 + j1 *
a_dim1], lda, &x[j1 + rhs * x_dim1], &scaloc, &
cnorm[1], info);
} else {
i__5 = j2 - j1;
slatrs_(uplo, trans, diag, "Y", &i__5, &a[j1 + j1 *
a_dim1], lda, &x[j1 + rhs * x_dim1], &scaloc, &
cnorm[1], info);
}
/* Find largest absolute value entry in the vector segment */
/* X( J1:J2-1, RHS ) as an upper bound for the worst case */
/* growth in the linear updates. */
i__5 = j2 - j1;
xnrm[kk - 1] = slange_("I", &i__5, &c__1, &x[j1 + rhs *
x_dim1], ldx, w);
if (scaloc == 0.f) {
/* LATRS found that A is singular through A(j,j) = 0. */
/* Reset the computation x(1:n) = 0, x(j) = 1, SCALE = 0 */
/* and compute A*x = 0 (or A**T*x = 0). Note that */
/* X(J1:J2-1, KK) is set by LATRS. */
scale[rhs] = 0.f;
i__5 = j1 - 1;
for (ii = 1; ii <= i__5; ++ii) {
x[ii + kk * x_dim1] = 0.f;
}
i__5 = *n;
for (ii = j2; ii <= i__5; ++ii) {
x[ii + kk * x_dim1] = 0.f;
}
/* Discard the local scale factors. */
i__5 = nba;
for (ii = 1; ii <= i__5; ++ii) {
work[ii + kk * lds] = 1.f;
}
scaloc = 1.f;
} else if (scaloc * work[j + kk * lds] == 0.f) {
/* LATRS computed a valid scale factor, but combined with */
/* the current scaling the solution does not have a */
/* scale factor > 0. */
/* Set WORK( J+KK*LDS ) to smallest valid scale */
/* factor and increase SCALOC accordingly. */
scal = work[j + kk * lds] / smlnum;
scaloc *= scal;
work[j + kk * lds] = smlnum;
/* If LATRS overestimated the growth, x may be */
/* rescaled to preserve a valid combined scale */
/* factor WORK( J, KK ) > 0. */
rscal = 1.f / scaloc;
if (xnrm[kk - 1] * rscal <= bignum) {
xnrm[kk - 1] *= rscal;
i__5 = j2 - j1;
sscal_(&i__5, &rscal, &x[j1 + rhs * x_dim1], &c__1);
scaloc = 1.f;
} else {
/* The system op(A) * x = b is badly scaled and its */
/* solution cannot be represented as (1/scale) * x. */
/* Set x to zero. This approach deviates from LATRS */
/* where a completely meaningless non-zero vector */
/* is returned that is not a solution to op(A) * x = b. */
scale[rhs] = 0.f;
i__5 = *n;
for (ii = 1; ii <= i__5; ++ii) {
x[ii + kk * x_dim1] = 0.f;
}
/* Discard the local scale factors. */
i__5 = nba;
for (ii = 1; ii <= i__5; ++ii) {
work[ii + kk * lds] = 1.f;
}
scaloc = 1.f;
}
}
scaloc *= work[j + kk * lds];
work[j + kk * lds] = scaloc;
}
/* Linear block updates */
if (notran) {
if (upper) {
ifirst = j - 1;
ilast = 1;
iinc = -1;
} else {
ifirst = j + 1;
ilast = nba;
iinc = 1;
}
} else {
if (upper) {
ifirst = j + 1;
ilast = nba;
iinc = 1;
} else {
ifirst = j - 1;
ilast = 1;
iinc = -1;
}
}
i__4 = ilast;
i__5 = iinc;
for (i__ = ifirst; i__5 < 0 ? i__ >= i__4 : i__ <= i__4; i__ +=
i__5) {
/* I1: row index of the first column in X( I, K ) */
/* I2: row index of the first column in X( I+1, K ) */
/* so the I2 - I1 is the row count of the block X( I, K ) */
i1 = (i__ - 1) * nb + 1;
/* Computing MIN */
i__6 = i__ * nb;
i2 = f2cmin(i__6,*n) + 1;
/* Prepare the linear update to be executed with GEMM. */
/* For each column, compute a consistent scaling, a */
/* scaling factor to survive the linear update, and */
/* rescale the column segments, if necesssary. Then */
/* the linear update is safely executed. */
i__6 = k2 - k1;
for (kk = 1; kk <= i__6; ++kk) {
rhs = k1 + kk - 1;
/* Compute consistent scaling */
/* Computing MIN */
r__1 = work[i__ + kk * lds], r__2 = work[j + kk * lds];
scamin = f2cmin(r__1,r__2);
/* Compute scaling factor to survive the linear update */
/* simulating consistent scaling. */
i__7 = i2 - i1;
bnrm = slange_("I", &i__7, &c__1, &x[i1 + rhs * x_dim1],
ldx, w);
bnrm *= scamin / work[i__ + kk * lds];
xnrm[kk - 1] *= scamin / work[j + kk * lds];
anrm = work[awrk + i__ + (j - 1) * nba];
scaloc = slarmm_(&anrm, &xnrm[kk - 1], &bnrm);
/* Simultaneously apply the robust update factor and the */
/* consistency scaling factor to B( I, KK ) and B( J, KK ). */
scal = scamin / work[i__ + kk * lds] * scaloc;
if (scal != 1.f) {
i__7 = i2 - i1;
sscal_(&i__7, &scal, &x[i1 + rhs * x_dim1], &c__1);
work[i__ + kk * lds] = scamin * scaloc;
}
scal = scamin / work[j + kk * lds] * scaloc;
if (scal != 1.f) {
i__7 = j2 - j1;
sscal_(&i__7, &scal, &x[j1 + rhs * x_dim1], &c__1);
work[j + kk * lds] = scamin * scaloc;
}
}
if (notran) {
/* B( I, K ) := B( I, K ) - A( I, J ) * X( J, K ) */
i__6 = i2 - i1;
i__7 = k2 - k1;
i__8 = j2 - j1;
sgemm_("N", "N", &i__6, &i__7, &i__8, &c_b35, &a[i1 + j1 *
a_dim1], lda, &x[j1 + k1 * x_dim1], ldx, &c_b36,
&x[i1 + k1 * x_dim1], ldx);
} else {
/* B( I, K ) := B( I, K ) - A( I, J )**T * X( J, K ) */
i__6 = i2 - i1;
i__7 = k2 - k1;
i__8 = j2 - j1;
sgemm_("T", "N", &i__6, &i__7, &i__8, &c_b35, &a[j1 + i1 *
a_dim1], lda, &x[j1 + k1 * x_dim1], ldx, &c_b36,
&x[i1 + k1 * x_dim1], ldx);
}
}
}
/* Reduce local scaling factors */
i__3 = k2 - k1;
for (kk = 1; kk <= i__3; ++kk) {
rhs = k1 + kk - 1;
i__2 = nba;
for (i__ = 1; i__ <= i__2; ++i__) {
/* Computing MIN */
r__1 = scale[rhs], r__2 = work[i__ + kk * lds];
scale[rhs] = f2cmin(r__1,r__2);
}
}
/* Realize consistent scaling */
i__3 = k2 - k1;
for (kk = 1; kk <= i__3; ++kk) {
rhs = k1 + kk - 1;
if (scale[rhs] != 1.f && scale[rhs] != 0.f) {
i__2 = nba;
for (i__ = 1; i__ <= i__2; ++i__) {
i1 = (i__ - 1) * nb + 1;
/* Computing MIN */
i__5 = i__ * nb;
i2 = f2cmin(i__5,*n) + 1;
scal = scale[rhs] / work[i__ + kk * lds];
if (scal != 1.f) {
i__5 = i2 - i1;
sscal_(&i__5, &scal, &x[i1 + rhs * x_dim1], &c__1);
}
}
}
}
}
return;
/* End of SLATRS3 */
} /* slatrs3_ */