magma_int_t magma_ztrevc3_mt(
magma_side_t side, magma_vec_t howmany,
magma_int_t *select, // logical in Fortran
magma_int_t n,
magmaDoubleComplex *T, magma_int_t ldt,
magmaDoubleComplex *VL, magma_int_t ldvl,
magmaDoubleComplex *VR, magma_int_t ldvr,
magma_int_t mm, magma_int_t *mout,
magmaDoubleComplex *work, magma_int_t lwork,
#ifdef COMPLEX
double *rwork,
#endif
magma_int_t *info )
{
#define T(i,j) ( T + (i) + (j)*ldt )
#define VL(i,j) (VL + (i) + (j)*ldvl)
#define VR(i,j) (VR + (i) + (j)*ldvr)
#define work(i,j) (work + (i) + (j)*n)
// .. Parameters ..
const magmaDoubleComplex c_zero = MAGMA_Z_ZERO;
const magmaDoubleComplex c_one = MAGMA_Z_ONE;
const magma_int_t nbmin = 16, nbmax = 128;
const magma_int_t ione = 1;
// .. Local Scalars ..
magma_int_t allv, bothv, leftv, over, rightv, somev;
magma_int_t i, ii, is, j, k, ki, iv, n2, nb, nb2, version;
double ovfl, remax, unfl; //smlnum, smin, ulp
// Decode and test the input parameters
bothv = (side == MagmaBothSides);
rightv = (side == MagmaRight) || bothv;
leftv = (side == MagmaLeft ) || bothv;
allv = (howmany == MagmaAllVec);
over = (howmany == MagmaBacktransVec);
somev = (howmany == MagmaSomeVec);
// Set mout to the number of columns required to store the selected
// eigenvectors.
if ( somev ) {
*mout = 0;
for( j=0; j < n; ++j ) {
if ( select[j] ) {
*mout += 1;
}
}
}
else {
*mout = n;
}
*info = 0;
if ( ! rightv && ! leftv )
*info = -1;
else if ( ! allv && ! over && ! somev )
*info = -2;
else if ( n < 0 )
*info = -4;
else if ( ldt < max( 1, n ) )
*info = -6;
else if ( ldvl < 1 || ( leftv && ldvl < n ) )
*info = -8;
else if ( ldvr < 1 || ( rightv && ldvr < n ) )
*info = -10;
else if ( mm < *mout )
*info = -11;
else if ( lwork < max( 1, 2*n ) )
*info = -14;
if ( *info != 0 ) {
magma_xerbla( __func__, -(*info) );
return *info;
}
// Quick return if possible.
if ( n == 0 ) {
return *info;
}
// Use blocked version (2) if sufficient workspace.
// Requires 1 vector to save diagonal elements, and 2*nb vectors for x and Q*x.
// (Compared to dtrevc3, rwork stores 1-norms.)
// Zero-out the workspace to avoid potential NaN propagation.
nb = 2;
if ( lwork >= n + 2*n*nbmin ) {
version = 2;
nb = (lwork - n) / (2*n);
nb = min( nb, nbmax );
nb2 = 1 + 2*nb;
lapackf77_zlaset( "F", &n, &nb2, &c_zero, &c_zero, work, &n );
}
else {
version = 1;
}
// Set the constants to control overflow.
unfl = lapackf77_dlamch( "Safe minimum" );
ovfl = 1. / unfl;
lapackf77_dlabad( &unfl, &ovfl );
//ulp = lapackf77_dlamch( "Precision" );
//smlnum = unfl*( n / ulp );
// Store the diagonal elements of T in working array work.
for( i=0; i < n; ++i ) {
*work(i,0) = *T(i,i);
}
// Compute 1-norm of each column of strictly upper triangular
// part of T to control overflow in triangular solver.
rwork[0] = 0.;
for( j=1; j < n; ++j ) {
rwork[j] = magma_cblas_dzasum( j, T(0,j), ione );
}
// launch threads -- each single-threaded MKL
magma_int_t nthread = magma_get_parallel_numthreads();
magma_int_t lapack_nthread = magma_get_lapack_numthreads();
magma_set_lapack_numthreads( 1 );
magma_thread_queue queue;
queue.launch( nthread );
//printf( "nthread %d, %d\n", nthread, lapack_nthread );
// gemm_nb = N/thread, rounded up to multiple of 16,
// but avoid multiples of page size, e.g., 512*8 bytes = 4096.
magma_int_t gemm_nb = magma_int_t( ceil( ceil( ((double)n) / nthread ) / 16. ) * 16. );
if ( gemm_nb % 512 == 0 ) {
gemm_nb += 32;
}
magma_timer_t time_total=0, time_trsv=0, time_gemm=0, time_gemv=0, time_trsv_sum=0, time_gemm_sum=0, time_gemv_sum=0;
timer_start( time_total );
if ( rightv ) {
// ============================================================
// Compute right eigenvectors.
// iv is index of column in current block.
// Non-blocked version always uses iv=1;
// blocked version starts with iv=nb, goes down to 1.
// (Note the "0-th" column is used to store the original diagonal.)
iv = 1;
if ( version == 2 ) {
iv = nb;
}
timer_start( time_trsv );
is = *mout - 1;
for( ki=n-1; ki >= 0; --ki ) {
if ( somev ) {
if ( ! select[ki] ) {
continue;
}
}
//smin = max( ulp*MAGMA_Z_ABS1( *T(ki,ki) ), smlnum );
// --------------------------------------------------------
// Complex right eigenvector
*work(ki,iv) = c_one;
// Form right-hand side.
for( k=0; k < ki; ++k ) {
*work(k,iv) = -(*T(k,ki));
}
// Solve upper triangular system:
// [ T(1:ki-1,1:ki-1) - T(ki,ki) ]*X = scale*work.
if ( ki > 0 ) {
queue.push_task( new magma_zlatrsd_task(
MagmaUpper, MagmaNoTrans, MagmaNonUnit, MagmaTrue,
ki, T, ldt, *T(ki,ki),
work(0,iv), work(ki,iv), rwork ));
}
// Copy the vector x or Q*x to VR and normalize.
if ( ! over ) {
// ------------------------------
// no back-transform: copy x to VR and normalize
queue.sync();
n2 = ki+1;
blasf77_zcopy( &n2, work(0,iv), &ione, VR(0,is), &ione );
ii = blasf77_izamax( &n2, VR(0,is), &ione ) - 1;
remax = 1. / MAGMA_Z_ABS1( *VR(ii,is) );
blasf77_zdscal( &n2, &remax, VR(0,is), &ione );
for( k=ki+1; k < n; ++k ) {
*VR(k,is) = c_zero;
}
}
else if ( version == 1 ) {
// ------------------------------
// version 1: back-transform each vector with GEMV, Q*x.
queue.sync();
time_trsv_sum += timer_stop( time_trsv );
timer_start( time_gemv );
if ( ki > 0 ) {
blasf77_zgemv( "n", &n, &ki, &c_one,
VR, &ldvr,
work(0, iv), &ione,
work(ki,iv), VR(0,ki), &ione );
}
time_gemv_sum += timer_stop( time_gemv );
ii = blasf77_izamax( &n, VR(0,ki), &ione ) - 1;
remax = 1. / MAGMA_Z_ABS1( *VR(ii,ki) );
blasf77_zdscal( &n, &remax, VR(0,ki), &ione );
timer_start( time_trsv );
}
else if ( version == 2 ) {
// ------------------------------
// version 2: back-transform block of vectors with GEMM
// zero out below vector
for( k=ki+1; k < n; ++k ) {
*work(k,iv) = c_zero;
}
// Columns iv:nb of work are valid vectors.
// When the number of vectors stored reaches nb,
// or if this was last vector, do the GEMM
if ( (iv == 1) || (ki == 0) ) {
queue.sync();
time_trsv_sum += timer_stop( time_trsv );
timer_start( time_gemm );
nb2 = nb-iv+1;
n2 = ki+nb-iv+1;
// split gemm into multiple tasks, each doing one block row
for( i=0; i < n; i += gemm_nb ) {
magma_int_t ib = min( gemm_nb, n-i );
queue.push_task( new zgemm_task(
MagmaNoTrans, MagmaNoTrans, ib, nb2, n2, c_one,
VR(i,0), ldvr,
work(0,iv ), n, c_zero,
work(i,nb+iv), n ));
}
queue.sync();
time_gemm_sum += timer_stop( time_gemm );
// normalize vectors
// TODO if somev, should copy vectors individually to correct location.
for( k = iv; k <= nb; ++k ) {
ii = blasf77_izamax( &n, work(0,nb+k), &ione ) - 1;
remax = 1. / MAGMA_Z_ABS1( *work(ii,nb+k) );
blasf77_zdscal( &n, &remax, work(0,nb+k), &ione );
}
lapackf77_zlacpy( "F", &n, &nb2, work(0,nb+iv), &n, VR(0,ki), &ldvr );
iv = nb;
timer_start( time_trsv );
}
else {
iv -= 1;
}
} // blocked back-transform
is -= 1;
}
}
timer_stop( time_trsv );
timer_stop( time_total );
timer_printf( "trevc trsv %.4f, gemm %.4f, gemv %.4f, total %.4f\n",
time_trsv_sum, time_gemm_sum, time_gemv_sum, time_total );
if ( leftv ) {
// ============================================================
// Compute left eigenvectors.
// iv is index of column in current block.
// Non-blocked version always uses iv=1;
// blocked version starts with iv=1, goes up to nb.
// (Note the "0-th" column is used to store the original diagonal.)
iv = 1;
is = 0;
for( ki=0; ki < n; ++ki ) {
if ( somev ) {
if ( ! select[ki] ) {
continue;
}
}
//smin = max( ulp*MAGMA_Z_ABS1( *T(ki,ki) ), smlnum );
// --------------------------------------------------------
// Complex left eigenvector
*work(ki,iv) = c_one;
// Form right-hand side.
for( k = ki + 1; k < n; ++k ) {
*work(k,iv) = -MAGMA_Z_CONJ( *T(ki,k) );
}
// Solve conjugate-transposed triangular system:
// [ T(ki+1:n,ki+1:n) - T(ki,ki) ]**H * X = scale*work.
// TODO what happens with T(k,k) - lambda is small? Used to have < smin test.
if ( ki < n-1 ) {
n2 = n-ki-1;
queue.push_task( new magma_zlatrsd_task(
MagmaUpper, MagmaConjTrans, MagmaNonUnit, MagmaTrue,
n2, T(ki+1,ki+1), ldt, *T(ki,ki),
work(ki+1,iv), work(ki,iv), rwork ));
}
// Copy the vector x or Q*x to VL and normalize.
if ( ! over ) {
// ------------------------------
// no back-transform: copy x to VL and normalize
queue.sync();
n2 = n-ki;
blasf77_zcopy( &n2, work(ki,iv), &ione, VL(ki,is), &ione );
ii = blasf77_izamax( &n2, VL(ki,is), &ione ) + ki - 1;
remax = 1. / MAGMA_Z_ABS1( *VL(ii,is) );
blasf77_zdscal( &n2, &remax, VL(ki,is), &ione );
for( k=0; k < ki; ++k ) {
*VL(k,is) = c_zero;
}
}
else if ( version == 1 ) {
// ------------------------------
// version 1: back-transform each vector with GEMV, Q*x.
queue.sync();
if ( ki < n-1 ) {
n2 = n-ki-1;
blasf77_zgemv( "n", &n, &n2, &c_one,
VL(0,ki+1), &ldvl,
work(ki+1,iv), &ione,
work(ki, iv), VL(0,ki), &ione );
}
ii = blasf77_izamax( &n, VL(0,ki), &ione ) - 1;
remax = 1. / MAGMA_Z_ABS1( *VL(ii,ki) );
blasf77_zdscal( &n, &remax, VL(0,ki), &ione );
}
else if ( version == 2 ) {
// ------------------------------
// version 2: back-transform block of vectors with GEMM
// zero out above vector
// could go from (ki+1)-NV+1 to ki
for( k=0; k < ki; ++k ) {
*work(k,iv) = c_zero;
}
// Columns 1:iv of work are valid vectors.
// When the number of vectors stored reaches nb,
// or if this was last vector, do the GEMM
if ( (iv == nb) || (ki == n-1) ) {
queue.sync();
n2 = n-(ki+1)+iv;
// split gemm into multiple tasks, each doing one block row
for( i=0; i < n; i += gemm_nb ) {
magma_int_t ib = min( gemm_nb, n-i );
queue.push_task( new zgemm_task(
MagmaNoTrans, MagmaNoTrans, ib, iv, n2, c_one,
VL(i,ki-iv+1), ldvl,
work(ki-iv+1,1), n, c_zero,
work(i,nb+1), n ));
}
queue.sync();
// normalize vectors
for( k=1; k <= iv; ++k ) {
ii = blasf77_izamax( &n, work(0,nb+k), &ione ) - 1;
remax = 1. / MAGMA_Z_ABS1( *work(ii,nb+k) );
blasf77_zdscal( &n, &remax, work(0,nb+k), &ione );
}
lapackf77_zlacpy( "F", &n, &iv, work(0,nb+1), &n, VL(0,ki-iv+1), &ldvl );
iv = 1;
}
else {
iv += 1;
}
} // blocked back-transform
is += 1;
}
}
// close down threads
queue.quit();
magma_set_lapack_numthreads( lapack_nthread );
return *info;
} // End of ZTREVC
// ----------------------------------------
int main( int argc, char** argv )
{
TESTING_INIT();
//real_Double_t t_m, t_c, t_f;
magma_int_t ione = 1;
magmaDoubleComplex *A, *B;
double error_cblas, error_fblas, error_inline;
magma_int_t ISEED[4] = {0,0,0,1};
magma_int_t i, j, k, m, n, size, maxn, ld;
// complex x for magma, cblas, fortran, inline blas respectively
magmaDoubleComplex x2_m, x2_c, x2_f, x2_i;
// real x for magma, cblas, fortran, inline blas respectively
double x_m, x_c, x_f, x_i;
MAGMA_UNUSED( x_c );
MAGMA_UNUSED( x_f );
MAGMA_UNUSED( x2_c );
MAGMA_UNUSED( x2_f );
MAGMA_UNUSED( x2_m );
magma_opts opts;
opts.parse_opts( argc, argv );
opts.tolerance = max( 100., opts.tolerance );
double tol = opts.tolerance * lapackf77_dlamch("E");
gTol = tol;
magma_int_t inc[] = { -2, -1, 1, 2 }; //{ 1 }; //{ -1, 1 };
magma_int_t ninc = sizeof(inc)/sizeof(*inc);
magma_int_t maxinc = 0;
for( i=0; i < ninc; ++i ) {
maxinc = max( maxinc, abs(inc[i]) );
}
printf( "!! Calling these CBLAS and Fortran BLAS sometimes crashes (segfaults), which !!\n"
"!! is why we use wrappers. It does not necesarily indicate a bug in MAGMA. !!\n"
"!! If MAGMA_WITH_MKL or __APPLE__ are defined, known failures are skipped. !!\n"
"\n" );
// tell user about disabled functions
#ifndef HAVE_CBLAS
printf( "n/a: HAVE_CBLAS not defined, so no cblas functions tested.\n\n" );
#endif
#if defined(MAGMA_WITH_MKL)
printf( "n/a: cblas_zdotc, cblas_zdotu, blasf77_zdotc, and blasf77_zdotu are disabled with MKL, due to segfaults.\n\n" );
#endif
#if defined(__APPLE__)
printf( "n/a: blasf77_zdotc and blasf77_zdotu are disabled on MacOS, due to segfaults.\n\n" );
#endif
printf( "%% Error w.r.t. Error w.r.t. Error w.r.t.\n"
"%% M N K incx incy Function CBLAS Fortran BLAS inline\n"
"%%====================================================================================\n" );
for( int itest = 0; itest < opts.ntest; ++itest ) {
if ( itest > 0 ) {
printf( "%%----------------------------------------------------------------------\n" );
}
m = opts.msize[itest];
n = opts.nsize[itest];
k = opts.ksize[itest];
// allocate matrices
// over-allocate so they can be any combination of
// {m,n,k} * {abs(incx), abs(incy)} by
// {m,n,k} * {abs(incx), abs(incy)}
maxn = max( max( m, n ), k ) * maxinc;
ld = max( 1, maxn );
size = ld*maxn;
TESTING_MALLOC_CPU( A, magmaDoubleComplex, size );
TESTING_MALLOC_CPU( B, magmaDoubleComplex, size );
// initialize matrices
lapackf77_zlarnv( &ione, ISEED, &size, A );
lapackf77_zlarnv( &ione, ISEED, &size, B );
// ----- test DZASUM
for( int iincx = 0; iincx < ninc; ++iincx ) {
magma_int_t incx = inc[iincx];
for( int iincy = 0; iincy < ninc; ++iincy ) {
magma_int_t incy = inc[iincy];
// get one-norm of column j of A
if ( incx > 0 && incx == incy ) { // positive, no incy
error_cblas = 0;
error_fblas = 0;
error_inline = 0;
for( j=0; j < k; ++j ) {
x_m = magma_cblas_dzasum( m, A(0,j), incx );
#ifdef HAVE_CBLAS
x_c = cblas_dzasum( m, A(0,j), incx );
error_cblas = max( error_cblas, fabs(x_m - x_c) / fabs(m*x_c) );
#else
x_c = 0;
error_cblas = SKIPPED_FLAG;
#endif
x_f = blasf77_dzasum( &m, A(0,j), &incx );
error_fblas = max( error_fblas, fabs(x_m - x_f) / fabs(m*x_f) );
// inline implementation
x_i = 0;
for( i=0; i < m; ++i ) {
x_i += MAGMA_Z_ABS1( *A(i*incx,j) ); // |real(Aij)| + |imag(Aij)|
}
error_inline = max( error_inline, fabs(x_m - x_i) / fabs(m*x_i) );
//printf( "dzasum xm %.8e, xc %.8e, xf %.8e, xi %.8e\n", x_m, x_c, x_f, x_i );
}
output( "dzasum", m, n, k, incx, incy, error_cblas, error_fblas, error_inline );
}
}
}
printf( "\n" );
// ----- test DZNRM2
// get two-norm of column j of A
for( int iincx = 0; iincx < ninc; ++iincx ) {
magma_int_t incx = inc[iincx];
for( int iincy = 0; iincy < ninc; ++iincy ) {
magma_int_t incy = inc[iincy];
if ( incx > 0 && incx == incy ) { // positive, no incy
error_cblas = 0;
error_fblas = 0;
error_inline = 0;
for( j=0; j < k; ++j ) {
x_m = magma_cblas_dznrm2( m, A(0,j), incx );
#ifdef HAVE_CBLAS
x_c = cblas_dznrm2( m, A(0,j), incx );
error_cblas = max( error_cblas, fabs(x_m - x_c) / fabs(m*x_c) );
#else
x_c = 0;
error_cblas = SKIPPED_FLAG;
#endif
x_f = blasf77_dznrm2( &m, A(0,j), &incx );
error_fblas = max( error_fblas, fabs(x_m - x_f) / fabs(m*x_f) );
// inline implementation (poor -- doesn't scale)
x_i = 0;
for( i=0; i < m; ++i ) {
x_i += real( *A(i*incx,j) ) * real( *A(i*incx,j) )
+ imag( *A(i*incx,j) ) * imag( *A(i*incx,j) );
// same: real( conj( *A(i*incx,j) ) * *A(i*incx,j) );
}
x_i = sqrt( x_i );
error_inline = max( error_inline, fabs(x_m - x_i) / fabs(m*x_i) );
//printf( "dznrm2 xm %.8e, xc %.8e, xf %.8e, xi %.8e\n", x_m, x_c, x_f, x_i );
}
output( "dznrm2", m, n, k, incx, incy, error_cblas, error_fblas, error_inline );
}
}
}
printf( "\n" );
// ----- test ZDOTC
// dot columns, Aj^H Bj
for( int iincx = 0; iincx < ninc; ++iincx ) {
magma_int_t incx = inc[iincx];
for( int iincy = 0; iincy < ninc; ++iincy ) {
magma_int_t incy = inc[iincy];
error_cblas = 0;
error_fblas = 0;
error_inline = 0;
for( j=0; j < k; ++j ) {
// MAGMA implementation, not just wrapper
x2_m = magma_cblas_zdotc( m, A(0,j), incx, B(0,j), incy );
// crashes with MKL 11.1.2, ILP64
#if defined(HAVE_CBLAS) && ! defined(MAGMA_WITH_MKL)
#ifdef COMPLEX
cblas_zdotc_sub( m, A(0,j), incx, B(0,j), incy, &x2_c );
#else
x2_c = cblas_zdotc( m, A(0,j), incx, B(0,j), incy );
#endif
error_cblas = max( error_cblas, fabs(x2_m - x2_c) / fabs(m*x2_c) );
#else
x2_c = MAGMA_Z_ZERO;
error_cblas = SKIPPED_FLAG;
#endif
// crashes with MKL 11.2.3 and MacOS 10.9
#if (! defined(COMPLEX) || ! defined(MAGMA_WITH_MKL)) && ! defined(__APPLE__)
x2_f = blasf77_zdotc( &m, A(0,j), &incx, B(0,j), &incy );
error_fblas = max( error_fblas, fabs(x2_m - x2_f) / fabs(m*x2_f) );
#else
x2_f = MAGMA_Z_ZERO;
error_fblas = SKIPPED_FLAG;
#endif
// inline implementation
x2_i = MAGMA_Z_ZERO;
magma_int_t A_offset = (incx > 0 ? 0 : (-n + 1)*incx);
magma_int_t B_offset = (incy > 0 ? 0 : (-n + 1)*incy);
for( i=0; i < m; ++i ) {
x2_i += conj( *A(A_offset + i*incx,j) ) * *B(B_offset + i*incy,j);
}
error_inline = max( error_inline, fabs(x2_m - x2_i) / fabs(m*x2_i) );
//printf( "zdotc xm %.8e + %.8ei, xc %.8e + %.8ei, xf %.8e + %.8ei, xi %.8e + %.8ei\n",
// real(x2_m), imag(x2_m),
// real(x2_c), imag(x2_c),
// real(x2_f), imag(x2_f),
// real(x2_i), imag(x2_i) );
}
output( "zdotc", m, n, k, incx, incy, error_cblas, error_fblas, error_inline );
}
}
printf( "\n" );
// ----- test ZDOTU
// dot columns, Aj^T * Bj
for( int iincx = 0; iincx < ninc; ++iincx ) {
magma_int_t incx = inc[iincx];
for( int iincy = 0; iincy < ninc; ++iincy ) {
magma_int_t incy = inc[iincy];
error_cblas = 0;
error_fblas = 0;
error_inline = 0;
for( j=0; j < k; ++j ) {
// MAGMA implementation, not just wrapper
x2_m = magma_cblas_zdotu( m, A(0,j), incx, B(0,j), incy );
// crashes with MKL 11.1.2, ILP64
#if defined(HAVE_CBLAS) && ! defined(MAGMA_WITH_MKL)
#ifdef COMPLEX
cblas_zdotu_sub( m, A(0,j), incx, B(0,j), incy, &x2_c );
#else
x2_c = cblas_zdotu( m, A(0,j), incx, B(0,j), incy );
#endif
error_cblas = max( error_cblas, fabs(x2_m - x2_c) / fabs(m*x2_c) );
#else
x2_c = MAGMA_Z_ZERO;
error_cblas = SKIPPED_FLAG;
#endif
// crashes with MKL 11.2.3 and MacOS 10.9
#if (! defined(COMPLEX) || ! defined(MAGMA_WITH_MKL)) && ! defined(__APPLE__)
x2_f = blasf77_zdotu( &m, A(0,j), &incx, B(0,j), &incy );
error_fblas = max( error_fblas, fabs(x2_m - x2_f) / fabs(m*x2_f) );
#else
x2_f = MAGMA_Z_ZERO;
error_fblas = SKIPPED_FLAG;
#endif
// inline implementation
x2_i = MAGMA_Z_ZERO;
magma_int_t A_offset = (incx > 0 ? 0 : (-n + 1)*incx);
magma_int_t B_offset = (incy > 0 ? 0 : (-n + 1)*incy);
for( i=0; i < m; ++i ) {
x2_i += *A(A_offset + i*incx,j) * *B(B_offset + i*incy,j);
}
error_inline = max( error_inline, fabs(x2_m - x2_i) / fabs(m*x2_i) );
//printf( "zdotu xm %.8e + %.8ei, xc %.8e + %.8ei, xf %.8e + %.8ei, xi %.8e + %.8ei\n",
// real(x2_m), imag(x2_m),
// real(x2_c), imag(x2_c),
// real(x2_f), imag(x2_f),
// real(x2_i), imag(x2_i) );
}
output( "zdotu", m, n, k, incx, incy, error_cblas, error_fblas, error_inline );
}
}
// cleanup
TESTING_FREE_CPU( A );
TESTING_FREE_CPU( B );
fflush( stdout );
} // itest, incx, incy
opts.cleanup();
TESTING_FINALIZE();
return gStatus;
}
// ----------------------------------------
int main( int argc, char** argv )
{
TESTING_INIT();
//real_Double_t t_m, t_c, t_f;
magma_int_t ione = 1;
magmaDoubleComplex *A, *B;
double diff, error;
magma_int_t ISEED[4] = {0,0,0,1};
magma_int_t m, n, k, size, maxn, ld;
magmaDoubleComplex x2_m, x2_c; // complex x for magma, cblas/fortran blas respectively
double x_m, x_c; // x for magma, cblas/fortran blas respectively
magma_opts opts;
parse_opts( argc, argv, &opts );
opts.tolerance = max( 100., opts.tolerance );
double tol = opts.tolerance * lapackf77_dlamch("E");
gTol = tol;
printf( "!! Calling these CBLAS and Fortran BLAS sometimes crashes (segfault), which !!\n"
"!! is why we use wrappers. It does not necesarily indicate a bug in MAGMA. !!\n"
"\n"
"Diff compares MAGMA wrapper to CBLAS and BLAS function; should be exactly 0.\n"
"Error compares MAGMA implementation to CBLAS and BLAS function; should be ~ machine epsilon.\n"
"\n" );
double total_diff = 0.;
double total_error = 0.;
int inc[] = { 1 }; //{ -2, -1, 1, 2 }; //{ 1 }; //{ -1, 1 };
int ninc = sizeof(inc)/sizeof(*inc);
for( int itest = 0; itest < opts.ntest; ++itest ) {
m = opts.msize[itest];
n = opts.nsize[itest];
k = opts.ksize[itest];
for( int iincx = 0; iincx < ninc; ++iincx ) {
magma_int_t incx = inc[iincx];
for( int iincy = 0; iincy < ninc; ++iincy ) {
magma_int_t incy = inc[iincy];
printf("=========================================================================\n");
printf( "m=%d, n=%d, k=%d, incx = %d, incy = %d\n",
(int) m, (int) n, (int) k, (int) incx, (int) incy );
printf( "Function MAGMA CBLAS BLAS Diff Error\n"
" msec msec msec\n" );
// allocate matrices
// over-allocate so they can be any combination of
// {m,n,k} * {abs(incx), abs(incy)} by
// {m,n,k} * {abs(incx), abs(incy)}
maxn = max( max( m, n ), k ) * max( abs(incx), abs(incy) );
ld = max( 1, maxn );
size = ld*maxn;
magma_zmalloc_pinned( &A, size ); assert( A != NULL );
magma_zmalloc_pinned( &B, size ); assert( B != NULL );
// initialize matrices
lapackf77_zlarnv( &ione, ISEED, &size, A );
lapackf77_zlarnv( &ione, ISEED, &size, B );
printf( "Level 1 BLAS ----------------------------------------------------------\n" );
// ----- test DZASUM
// get one-norm of column j of A
if ( incx > 0 && incx == incy ) { // positive, no incy
diff = 0;
error = 0;
for( int j = 0; j < k; ++j ) {
x_m = magma_cblas_dzasum( m, A(0,j), incx );
x_c = cblas_dzasum( m, A(0,j), incx );
diff += fabs( x_m - x_c );
x_c = blasf77_dzasum( &m, A(0,j), &incx );
error += fabs( (x_m - x_c) / (m*x_c) );
}
output( "dzasum", diff, error );
total_diff += diff;
total_error += error;
}
// ----- test DZNRM2
// get two-norm of column j of A
if ( incx > 0 && incx == incy ) { // positive, no incy
diff = 0;
error = 0;
for( int j = 0; j < k; ++j ) {
x_m = magma_cblas_dznrm2( m, A(0,j), incx );
x_c = cblas_dznrm2( m, A(0,j), incx );
diff += fabs( x_m - x_c );
x_c = blasf77_dznrm2( &m, A(0,j), &incx );
error += fabs( (x_m - x_c) / (m*x_c) );
}
output( "dznrm2", diff, error );
total_diff += diff;
total_error += error;
}
// ----- test ZDOTC
// dot columns, Aj^H Bj
diff = 0;
error = 0;
for( int j = 0; j < k; ++j ) {
// MAGMA implementation, not just wrapper
x2_m = magma_cblas_zdotc( m, A(0,j), incx, B(0,j), incy );
// crashes on MKL 11.1.2, ILP64
#if ! defined( MAGMA_WITH_MKL )
#ifdef COMPLEX
cblas_zdotc_sub( m, A(0,j), incx, B(0,j), incy, &x2_c );
#else
x2_c = cblas_zdotc( m, A(0,j), incx, B(0,j), incy );
#endif
error += fabs( x2_m - x2_c ) / fabs( m*x2_c );
#endif
// crashes on MacOS 10.9
#if ! defined( __APPLE__ )
x2_c = blasf77_zdotc( &m, A(0,j), &incx, B(0,j), &incy );
error += fabs( x2_m - x2_c ) / fabs( m*x2_c );
#endif
}
output( "zdotc", diff, error );
total_diff += diff;
total_error += error;
total_error += error;
// ----- test ZDOTU
// dot columns, Aj^T * Bj
diff = 0;
error = 0;
for( int j = 0; j < k; ++j ) {
// MAGMA implementation, not just wrapper
x2_m = magma_cblas_zdotu( m, A(0,j), incx, B(0,j), incy );
// crashes on MKL 11.1.2, ILP64
#if ! defined( MAGMA_WITH_MKL )
#ifdef COMPLEX
cblas_zdotu_sub( m, A(0,j), incx, B(0,j), incy, &x2_c );
#else
x2_c = cblas_zdotu( m, A(0,j), incx, B(0,j), incy );
#endif
error += fabs( x2_m - x2_c ) / fabs( m*x2_c );
#endif
// crashes on MacOS 10.9
#if ! defined( __APPLE__ )
x2_c = blasf77_zdotu( &m, A(0,j), &incx, B(0,j), &incy );
error += fabs( x2_m - x2_c ) / fabs( m*x2_c );
#endif
}
output( "zdotu", diff, error );
total_diff += diff;
total_error += error;
// tell user about disabled functions
#if defined( MAGMA_WITH_MKL )
printf( "cblas_zdotc and cblas_zdotu disabled with MKL (segfaults)\n" );
#endif
#if defined( __APPLE__ )
printf( "blasf77_zdotc and blasf77_zdotu disabled on MacOS (segfaults)\n" );
#endif
// cleanup
magma_free_pinned( A );
magma_free_pinned( B );
fflush( stdout );
}}} // itest, incx, incy
// TODO use average error?
printf( "sum diffs = %8.2g, MAGMA wrapper compared to CBLAS and Fortran BLAS; should be exactly 0.\n"
"sum errors = %8.2e, MAGMA implementation compared to CBLAS and Fortran BLAS; should be ~ machine epsilon.\n\n",
total_diff, total_error );
if ( total_diff != 0. ) {
printf( "some tests failed diff == 0.; see above.\n" );
}
else {
printf( "all tests passed diff == 0.\n" );
}
TESTING_FINALIZE();
int status = (total_diff != 0.);
return status;
}
magma_int_t magma_zlatrsd(
magma_uplo_t uplo, magma_trans_t trans, magma_diag_t diag, magma_bool_t normin,
magma_int_t n, const magmaDoubleComplex *A, magma_int_t lda,
magmaDoubleComplex lambda,
magmaDoubleComplex *x,
double *scale, double *cnorm,
magma_int_t *info)
{
#define A(i,j) (A + (i) + (j)*lda)
/* constants */
const magma_int_t ione = 1;
const double d_half = 0.5;
const magmaDoubleComplex c_zero = MAGMA_Z_ZERO;
const magmaDoubleComplex c_one = MAGMA_Z_ONE;
/* System generated locals */
magma_int_t len;
magmaDoubleComplex ztmp;
/* Local variables */
magma_int_t i, j;
double xj, rec, tjj;
magma_int_t jinc;
double xbnd;
magma_int_t imax;
double tmax;
magmaDoubleComplex tjjs;
double xmax, grow;
double tscal;
magmaDoubleComplex uscal;
magma_int_t jlast;
magmaDoubleComplex csumj;
double bignum;
magma_int_t jfirst;
double smlnum;
/* Function Body */
*info = 0;
magma_int_t upper = (uplo == MagmaUpper);
magma_int_t notran = (trans == MagmaNoTrans);
magma_int_t nounit = (diag == MagmaNonUnit);
/* Test the input parameters. */
if ( ! upper && uplo != MagmaLower ) {
*info = -1;
}
else if (! notran &&
trans != MagmaTrans &&
trans != MagmaConjTrans) {
*info = -2;
}
else if ( ! nounit && diag != MagmaUnit ) {
*info = -3;
}
else if ( ! (normin == MagmaTrue) &&
! (normin == MagmaFalse) ) {
*info = -4;
}
else if ( n < 0 ) {
*info = -5;
}
else if ( lda < max(1,n) ) {
*info = -7;
}
if ( *info != 0 ) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( n == 0 ) {
return *info;
}
/* Determine machine dependent parameters to control overflow. */
smlnum = lapackf77_dlamch( "Safe minimum" );
bignum = 1. / smlnum;
lapackf77_dlabad( &smlnum, &bignum );
smlnum /= lapackf77_dlamch( "Precision" );
bignum = 1. / smlnum;
*scale = 1.;
if ( normin == MagmaFalse ) {
/* Compute the 1-norm of each column, not including the diagonal. */
if ( upper ) {
/* A is upper triangular. */
cnorm[0] = 0.;
for( j = 1; j < n; ++j ) {
cnorm[j] = magma_cblas_dzasum( j, A(0,j), ione );
}
}
else {
/* A is lower triangular. */
for( j = 0; j < n-1; ++j ) {
cnorm[j] = magma_cblas_dzasum( n-(j+1), A(j+1,j), ione );
}
cnorm[n-1] = 0.;
}
}
/* Scale the column norms by TSCAL if the maximum element in CNORM is */
/* greater than BIGNUM/2. */
imax = blasf77_idamax( &n, &cnorm[0], &ione ) - 1;
tmax = cnorm[imax];
if ( tmax <= bignum * 0.5 ) {
tscal = 1.;
}
else {
tscal = 0.5 / (smlnum * tmax);
blasf77_dscal( &n, &tscal, &cnorm[0], &ione );
}
/* ================================================================= */
/* Compute a bound on the computed solution vector to see if the */
/* Level 2 BLAS routine ZTRSV can be used. */
xmax = 0.;
for( j = 0; j < n; ++j ) {
xmax = max( xmax, 0.5*MAGMA_Z_ABS1( x[j] ));
}
xbnd = xmax;
if ( notran ) {
/* ---------------------------------------- */
/* Compute the growth in A * x = b. */
if ( upper ) {
jfirst = n-1;
jlast = 0;
jinc = -1;
}
else {
jfirst = 0;
jlast = n;
jinc = 1;
}
if ( tscal != 1. ) {
grow = 0.;
goto L60;
}
/* A is non-unit triangular. */
/* Compute GROW = 1/G(j) and XBND = 1/M(j). */
/* Initially, G(0) = max{x(i), i=1,...,n}. */
grow = 0.5 / max( xbnd, smlnum );
xbnd = grow;
for( j = jfirst; (jinc < 0 ? j >= jlast : j < jlast); j += jinc ) {
/* Exit the loop if the growth factor is too small. */
if ( grow <= smlnum ) {
goto L60;
}
if ( nounit ) {
tjjs = *A(j,j) - lambda;
}
else {
tjjs = c_one - lambda;
}
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj >= smlnum ) {
/* M(j) = G(j-1) / abs(A(j,j)) */
xbnd = min( xbnd, min(1.,tjj)*grow );
}
else {
/* M(j) could overflow, set XBND to 0. */
xbnd = 0.;
}
if ( tjj + cnorm[j] >= smlnum ) {
/* G(j) = G(j-1)*( 1 + CNORM(j) / abs(A(j,j)) ) */
grow *= (tjj / (tjj + cnorm[j]));
}
else {
/* G(j) could overflow, set GROW to 0. */
grow = 0.;
}
}
grow = xbnd;
L60:
;
}
else {
/* ---------------------------------------- */
/* Compute the growth in A**T * x = b or A**H * x = b. */
if ( upper ) {
jfirst = 0;
jlast = n;
jinc = 1;
}
else {
jfirst = n-1;
jlast = 0;
jinc = -1;
}
if ( tscal != 1. ) {
grow = 0.;
goto L90;
}
/* A is non-unit triangular. */
/* Compute GROW = 1/G(j) and XBND = 1/M(j). */
/* Initially, M(0) = max{x(i), i=1,...,n}. */
grow = 0.5 / max( xbnd, smlnum );
xbnd = grow;
for( j = jfirst; (jinc < 0 ? j >= jlast : j < jlast); j += jinc ) {
/* Exit the loop if the growth factor is too small. */
if ( grow <= smlnum ) {
goto L90;
}
/* G(j) = max( G(j-1), M(j-1)*( 1 + CNORM(j) ) ) */
xj = 1. + cnorm[j];
grow = min( grow, xbnd / xj );
if ( nounit ) {
tjjs = *A(j,j) - lambda;
}
else {
tjjs = c_one - lambda;
}
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj >= smlnum ) {
/* M(j) = M(j-1)*( 1 + CNORM(j) ) / abs(A(j,j)) */
if ( xj > tjj ) {
xbnd *= (tjj / xj);
}
}
else {
/* M(j) could overflow, set XBND to 0. */
xbnd = 0.;
}
}
grow = min( grow, xbnd );
L90:
;
}
/* ================================================================= */
/* Due to modified diagonal, we can't use regular BLAS ztrsv. */
/* Use a Level 1 BLAS solve, scaling intermediate results. */
if ( xmax > bignum * 0.5 ) {
/* Scale X so that its components are less than or equal to */
/* BIGNUM in absolute value. */
*scale = (bignum * 0.5) / xmax;
blasf77_zdscal( &n, scale, &x[0], &ione );
xmax = bignum;
}
else {
xmax *= 2.;
}
if ( notran ) {
/* ---------------------------------------- */
/* Solve A * x = b */
for( j = jfirst; (jinc < 0 ? j >= jlast : j < jlast); j += jinc ) {
/* Compute x(j) = b(j) / A(j,j), scaling x if necessary. */
xj = MAGMA_Z_ABS1( x[j] );
if ( nounit ) {
tjjs = (*A(j,j) - lambda ) * tscal;
}
else {
tjjs = (c_one - lambda) * tscal;
if ( tscal == 1. ) {
goto L110;
}
}
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj > smlnum ) {
/* abs(A(j,j)) > SMLNUM: */
if ( tjj < 1. ) {
if ( xj > tjj * bignum ) {
/* Scale x by 1/b(j). */
rec = 1. / xj;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
}
x[j] = x[j] / tjjs;
xj = MAGMA_Z_ABS1( x[j] );
}
else if ( tjj > 0. ) {
/* 0 < abs(A(j,j)) <= SMLNUM: */
if ( xj > tjj * bignum ) {
/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM */
/* to avoid overflow when dividing by A(j,j). */
rec = (tjj * bignum) / xj;
if ( cnorm[j] > 1. ) {
/* Scale by 1/CNORM(j) to avoid overflow when */
/* multiplying x(j) times column j. */
rec /= cnorm[j];
}
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
x[j] = x[j] / tjjs;
xj = MAGMA_Z_ABS1( x[j] );
}
else {
/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */
/* scale = 0, and compute a solution to A*x = 0. */
for( i = 0; i < n; ++i ) {
x[i] = c_zero;
}
x[j] = c_one;
xj = 1.;
*scale = 0.;
xmax = 0.;
}
L110:
/* Scale x if necessary to avoid overflow when adding a */
/* multiple of column j of A. */
if ( xj > 1. ) {
rec = 1. / xj;
if ( cnorm[j] > (bignum - xmax) * rec ) {
/* Scale x by 1/(2*abs(x(j))). */
rec *= 0.5;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
}
}
else if ( xj * cnorm[j] > bignum - xmax ) {
/* Scale x by 1/2. */
blasf77_zdscal( &n, &d_half, &x[0], &ione );
*scale *= 0.5;
}
if ( upper ) {
if ( j > 0 ) {
/* Compute the update */
/* x(1:j-1) := x(1:j-1) - x(j) * A(1:j-1,j) */
len = j;
ztmp = -tscal * x[j];
blasf77_zaxpy( &len, &ztmp, A(0,j), &ione, &x[0], &ione );
i = blasf77_izamax( &len, &x[0], &ione ) - 1;
xmax = MAGMA_Z_ABS1( x[i] );
}
}
else {
if ( j < n-1 ) {
/* Compute the update */
/* x(j+1:n) := x(j+1:n) - x(j) * A(j+1:n,j) */
len = n - (j+1);
ztmp = -tscal * x[j];
blasf77_zaxpy( &len, &ztmp, A(j+1,j), &ione, &x[j + 1], &ione );
i = j + blasf77_izamax( &len, &x[j + 1], &ione );
xmax = MAGMA_Z_ABS1( x[i] );
}
}
}
}
else if ( trans == MagmaTrans ) {
/* ---------------------------------------- */
/* Solve A**T * x = b */
for( j = jfirst; (jinc < 0 ? j >= jlast : j < jlast); j += jinc ) {
/* Compute x(j) = b(j) - sum A(k,j)*x(k). */
/* k<>j */
xj = MAGMA_Z_ABS1( x[j] );
uscal = MAGMA_Z_MAKE( tscal, 0. );
rec = 1. / max( xmax, 1. );
if ( cnorm[j] > (bignum - xj) * rec ) {
/* If x(j) could overflow, scale x by 1/(2*XMAX). */
rec *= 0.5;
if ( nounit ) {
tjjs = (*A(j,j) - lambda) * tscal;
}
else {
tjjs = (c_one - lambda) * tscal;
}
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj > 1. ) {
/* Divide by A(j,j) when scaling x if A(j,j) > 1. */
rec = min( 1., rec * tjj );
uscal = uscal / tjjs;
}
if ( rec < 1. ) {
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
}
csumj = c_zero;
if ( uscal == c_one ) {
/* If the scaling needed for A in the dot product is 1, */
/* call ZDOTU to perform the dot product. */
if ( upper ) {
csumj = magma_cblas_zdotu( j, A(0,j), ione, &x[0], ione );
}
else if ( j < n-1 ) {
csumj = magma_cblas_zdotu( n-(j+1), A(j+1,j), ione, &x[j+1], ione );
}
}
else {
/* Otherwise, use in-line code for the dot product. */
if ( upper ) {
for( i = 0; i < j; ++i ) {
csumj += (*A(i,j) * uscal) * x[i];
}
}
else if ( j < n-1 ) {
for( i = j+1; i < n; ++i ) {
csumj += (*A(i,j) * uscal) * x[i];
}
}
}
if ( uscal == MAGMA_Z_MAKE( tscal, 0. )) {
/* Compute x(j) := ( x(j) - CSUMJ ) / A(j,j) if 1/A(j,j) */
/* was not used to scale the dotproduct. */
x[j] -= csumj;
xj = MAGMA_Z_ABS1( x[j] );
if ( nounit ) {
tjjs = (*A(j,j) - lambda) * tscal;
}
else {
tjjs = (c_one - lambda) * tscal;
if ( tscal == 1. ) {
goto L160;
}
}
/* Compute x(j) = x(j) / A(j,j), scaling if necessary. */
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj > smlnum ) {
/* abs(A(j,j)) > SMLNUM: */
if ( tjj < 1. ) {
if ( xj > tjj * bignum ) {
/* Scale X by 1/abs(x(j)). */
rec = 1. / xj;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
}
x[j] = x[j] / tjjs;
}
else if ( tjj > 0. ) {
/* 0 < abs(A(j,j)) <= SMLNUM: */
if ( xj > tjj * bignum ) {
/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM. */
rec = (tjj * bignum) / xj;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
x[j] = x[j] / tjjs;
}
else {
/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */
/* scale = 0 and compute a solution to A**T *x = 0. */
for( i = 0; i < n; ++i ) {
x[i] = c_zero;
}
x[j] = c_one;
*scale = 0.;
xmax = 0.;
}
L160:
;
}
else {
/* Compute x(j) := x(j) / A(j,j) - CSUMJ if the dot */
/* product has already been divided by 1/A(j,j). */
x[j] = (x[j] / tjjs) - csumj;
}
xmax = max( xmax, MAGMA_Z_ABS1( x[j] ));
}
}
else {
/* ---------------------------------------- */
/* Solve A**H * x = b */
for( j = jfirst; (jinc < 0 ? j >= jlast : j < jlast); j += jinc ) {
/* Compute x(j) = b(j) - sum A(k,j)*x(k). */
/* k<>j */
xj = MAGMA_Z_ABS1( x[j] );
uscal = MAGMA_Z_MAKE( tscal, 0. );
rec = 1. / max(xmax, 1.);
if ( cnorm[j] > (bignum - xj) * rec ) {
/* If x(j) could overflow, scale x by 1/(2*XMAX). */
rec *= 0.5;
if ( nounit ) {
tjjs = MAGMA_Z_CONJ( *A(j,j) - lambda ) * tscal;
}
else {
tjjs = (c_one - lambda) * tscal;
}
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj > 1. ) {
/* Divide by A(j,j) when scaling x if A(j,j) > 1. */
rec = min( 1., rec * tjj );
uscal = uscal / tjjs;
}
if ( rec < 1. ) {
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
}
csumj = c_zero;
if ( uscal == c_one ) {
/* If the scaling needed for A in the dot product is 1, */
/* call ZDOTC to perform the dot product. */
if ( upper ) {
csumj = magma_cblas_zdotc( j, A(0,j), ione, &x[0], ione );
}
else if ( j < n-1 ) {
csumj = magma_cblas_zdotc( n-(j+1), A(j+1,j), ione, &x[j+1], ione );
}
}
else {
/* Otherwise, use in-line code for the dot product. */
if ( upper ) {
for( i = 0; i < j; ++i ) {
csumj += (MAGMA_Z_CONJ( *A(i,j) ) * uscal) * x[i];
}
}
else if ( j < n-1 ) {
for( i = j + 1; i < n; ++i ) {
csumj += (MAGMA_Z_CONJ( *A(i,j) ) * uscal) * x[i];
}
}
}
if ( uscal == tscal ) {
/* Compute x(j) := ( x(j) - CSUMJ ) / A(j,j) if 1/A(j,j) */
/* was not used to scale the dotproduct. */
x[j] -= csumj;
xj = MAGMA_Z_ABS1( x[j] );
if ( nounit ) {
tjjs = MAGMA_Z_CONJ( *A(j,j) - lambda ) * tscal;
}
else {
tjjs = (c_one - lambda) * tscal;
if ( tscal == 1. ) {
goto L210;
}
}
/* Compute x(j) = x(j) / A(j,j), scaling if necessary. */
tjj = MAGMA_Z_ABS1( tjjs );
if ( tjj > smlnum ) {
/* abs(A(j,j)) > SMLNUM: */
if ( tjj < 1. ) {
if ( xj > tjj * bignum ) {
/* Scale X by 1/abs(x(j)). */
rec = 1. / xj;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
}
x[j] = x[j] / tjjs;
}
else if ( tjj > 0. ) {
/* 0 < abs(A(j,j)) <= SMLNUM: */
if ( xj > tjj * bignum ) {
/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM. */
rec = (tjj * bignum) / xj;
blasf77_zdscal( &n, &rec, &x[0], &ione );
*scale *= rec;
xmax *= rec;
}
x[j] = x[j] / tjjs;
}
else {
/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */
/* scale = 0 and compute a solution to A**H *x = 0. */
for( i = 0; i < n; ++i ) {
x[i] = c_zero;
}
x[j] = c_one;
*scale = 0.;
xmax = 0.;
}
L210:
;
}
else {
/* Compute x(j) := x(j) / A(j,j) - CSUMJ if the dot */
/* product has already been divided by 1/A(j,j). */
x[j] = (x[j] / tjjs) - csumj;
}
xmax = max( xmax, MAGMA_Z_ABS1( x[j] ));
}
}
*scale /= tscal;
/* Scale the column norms by 1/TSCAL for return. */
if ( tscal != 1. ) {
double d = 1. / tscal;
blasf77_dscal( &n, &d, &cnorm[0], &ione );
}
return *info;
} /* end zlatrsd */