示例#1
0
/* ////////////////////////////////////////////////////////////////////////////
   -- Testing ssygvdx
*/
int main( int argc, char** argv)
{

    TESTING_INIT_MGPU();

    real_Double_t   mgpu_time;
    float *h_A, *h_Ainit, *h_B, *h_Binit, *h_work;

#if defined(PRECISION_z) || defined(PRECISION_c)
    float *rwork;
    magma_int_t lrwork;
#endif

    float *w1, result=0;
    magma_int_t *iwork;
    magma_int_t N, n2, info, lwork, liwork;
    float c_zero    = MAGMA_S_ZERO;
    float c_one     = MAGMA_S_ONE;
    float c_neg_one = MAGMA_S_NEG_ONE;
    magma_int_t ione     = 1;
    magma_int_t ISEED[4] = {0,0,0,1};
    magma_int_t status = 0;

    magma_opts opts;
    parse_opts( argc, argv, &opts );
    
    float tol = opts.tolerance * lapackf77_slamch("E");

    magma_range_t range = MagmaRangeAll;
    if (opts.fraction != 1)
        range = MagmaRangeI;

    if ( opts.check && opts.jobz == MagmaNoVec ) {
        fprintf( stderr, "checking results requires vectors; setting jobz=V (option -JV)\n" );
        opts.jobz = MagmaVec;
    }

    printf("using: ngpu = %d, itype = %d, jobz = %s, range = %s, uplo = %s, opts.check = %d, fraction = %6.4f\n",
           (int) opts.ngpu, (int) opts.itype,
           lapack_vec_const(opts.jobz), lapack_range_const(range), lapack_uplo_const(opts.uplo),
           (int) opts.check, opts.fraction);
    
    printf("    N     M   ngpu   MGPU Time (sec)\n");
    printf("====================================\n");
    magma_int_t threads = magma_get_parallel_numthreads();
    for( int itest = 0; itest < opts.ntest; ++itest ) {
        for( int iter = 0; iter < opts.niter; ++iter ) {
            N = opts.nsize[itest];
            n2     = N*N;
            #if defined(PRECISION_z) || defined(PRECISION_c)
            lwork  = magma_sbulge_get_lq2(N, threads) + 2*N + N*N;
            lrwork = 1 + 5*N +2*N*N;
            #else
            lwork  = magma_sbulge_get_lq2(N, threads) + 1 + 6*N + 2*N*N;
            #endif
            liwork = 3 + 5*N;


            //magma_int_t NB = 96;//magma_bulge_get_nb(N);
            //magma_int_t sizvblg = magma_sbulge_get_lq2(N, threads);        
            //magma_int_t siz = max(sizvblg,n2)+2*(N*NB+N)+24*N; 
            /* Allocate host memory for the matrix */
            TESTING_MALLOC_PIN( h_A,    float, n2 );
            TESTING_MALLOC_PIN( h_B,    float, n2 );
            TESTING_MALLOC_PIN( h_work, float, lwork );
            #if defined(PRECISION_z) || defined(PRECISION_c)
            TESTING_MALLOC_PIN( rwork,  float, lrwork);
            #endif

            TESTING_MALLOC_CPU( w1,     float, N );
            TESTING_MALLOC_CPU( iwork,  magma_int_t, liwork);
            
            /* Initialize the matrix */
            lapackf77_slarnv( &ione, ISEED, &n2, h_A );
            lapackf77_slarnv( &ione, ISEED, &n2, h_B );
            magma_smake_hpd( N, h_B, N );
            magma_smake_symmetric( N, h_A, N );

            if ( opts.warmup || opts.check ) {
                TESTING_MALLOC_CPU( h_Ainit, float, n2 );
                TESTING_MALLOC_CPU( h_Binit, float, n2 );
                lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_A, &N, h_Ainit, &N );
                lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_B, &N, h_Binit, &N );
            }



            magma_int_t m1 = 0;
            float vl = 0;
            float vu = 0;
            magma_int_t il = 0;
            magma_int_t iu = 0;

            if (range == MagmaRangeI) {
                il = 1;
                iu = (int) (opts.fraction*N);
            }

            if ( opts.warmup ) {

                // ==================================================================
                // Warmup using MAGMA. I prefer to use smalltest to warmup A-
                // ==================================================================
                magma_ssygvdx_2stage_m(opts.ngpu, opts.itype, opts.jobz, range, opts.uplo,
                                       N, h_A, N, h_B, N, vl, vu, il, iu, &m1, w1,
                                       h_work, lwork,
                                       #if defined(PRECISION_z) || defined(PRECISION_c)
                                       rwork, lrwork,
                                       #endif
                                       iwork, liwork,
                                       &info);
                lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_Ainit, &N, h_A, &N );
                lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_Binit, &N, h_B, &N );
            }

            // ===================================================================
            // Performs operation using MAGMA
            // ===================================================================

            mgpu_time = magma_wtime();
            magma_ssygvdx_2stage_m(opts.ngpu, opts.itype, opts.jobz, range, opts.uplo,
                                   N, h_A, N, h_B, N, vl, vu, il, iu, &m1, w1,
                                   h_work, lwork,
                                       #if defined(PRECISION_z) || defined(PRECISION_c)
                                   rwork, lrwork,
                                       #endif
                                   iwork, liwork,
                                   &info);
            mgpu_time = magma_wtime() - mgpu_time;

            if ( opts.check ) {
                // ===================================================================
                // Check the results following the LAPACK's [zc]hegvdx routine.
                // A x = lambda B x is solved
                // and the following 3 tests computed:
                // (1)    | A Z - B Z D | / ( |A||Z| N )  (itype = 1)
                // | A B Z - Z D | / ( |A||Z| N )  (itype = 2)
                // | B A Z - Z D | / ( |A||Z| N )  (itype = 3)
                // ===================================================================
                #if defined(PRECISION_d) || defined(PRECISION_s)
                float *rwork = h_work + N*N;
                #endif
                result = 1.;
                result /= lapackf77_slansy("1", lapack_uplo_const(opts.uplo), &N, h_Ainit, &N, rwork);
                result /= lapackf77_slange("1", &N , &m1, h_A, &N, rwork);

                if (opts.itype == 1) {
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_one, h_Ainit, &N, h_A, &N, &c_zero, h_work, &N);
                    for(int i=0; i<m1; ++i)
                        blasf77_sscal(&N, &w1[i], &h_A[i*N], &ione);
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_neg_one, h_Binit, &N, h_A, &N, &c_one, h_work, &N);
                    result *= lapackf77_slange("1", &N, &m1, h_work, &N, rwork)/N;
                }
                else if (opts.itype == 2) {
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_one, h_Binit, &N, h_A, &N, &c_zero, h_work, &N);
                    for(int i=0; i<m1; ++i)
                        blasf77_sscal(&N, &w1[i], &h_A[i*N], &ione);
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_one, h_Ainit, &N, h_work, &N, &c_neg_one, h_A, &N);
                    result *= lapackf77_slange("1", &N, &m1, h_A, &N, rwork)/N;
                }
                else if (opts.itype == 3) {
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_one, h_Ainit, &N, h_A, &N, &c_zero, h_work, &N);
                    for(int i=0; i<m1; ++i)
                        blasf77_sscal(&N, &w1[i], &h_A[i*N], &ione);
                    blasf77_ssymm("L", lapack_uplo_const(opts.uplo), &N, &m1, &c_one, h_Binit, &N, h_work, &N, &c_neg_one, h_A, &N);
                    result *= lapackf77_slange("1", &N, &m1, h_A, &N, rwork)/N;
                }
            }

            // ===================================================================
            // Print execution time
            // ===================================================================
            printf("%5d %5d   %4d   %7.2f\n",
                   (int) N, (int) m1, (int) opts.ngpu, mgpu_time);
            if ( opts.check ) {
                printf("Testing the eigenvalues and eigenvectors for correctness:\n");
                if (opts.itype==1) {
                    printf("(1)    | A Z - B Z D | / (|A| |Z| N) = %8.2e   %s\n", result, (result < tol ? "ok" : "failed") );
                }
                else if (opts.itype==2) {
                    printf("(1)    | A B Z - Z D | / (|A| |Z| N) = %8.2e   %s\n", result, (result < tol ? "ok" : "failed") );
                }
                else if (opts.itype==3) {
                    printf("(1)    | B A Z - Z D | / (|A| |Z| N) = %8.2e   %s\n", result, (result < tol ? "ok" : "failed") );
                }
                printf("\n");
                status += ! (result < tol);
            }

            TESTING_FREE_PIN( h_A    );
            TESTING_FREE_PIN( h_B    );
            TESTING_FREE_PIN( h_work );
            #if defined(PRECISION_z) || defined(PRECISION_c)
            TESTING_FREE_PIN( rwork  );
            #endif

            TESTING_FREE_CPU( w1    );
            TESTING_FREE_CPU( iwork );
            if ( opts.warmup || opts.check ) {
                TESTING_FREE_CPU( h_Ainit );
                TESTING_FREE_CPU( h_Binit );
            }
            fflush( stdout );
        }
        if ( opts.niter > 1 ) {
            printf( "\n" );
        }
    }

    /* Shutdown */
    TESTING_FINALIZE_MGPU();
    return status;
}
示例#2
0
extern "C" magma_int_t
magma_ssygvdx_2stage(magma_int_t itype, char jobz, char range, char uplo, magma_int_t n,
                     float *a, magma_int_t lda, float *b, magma_int_t ldb,
                     float vl, float vu, magma_int_t il, magma_int_t iu,
                     magma_int_t *m, float *w, float *work, magma_int_t lwork,
                     magma_int_t *iwork, magma_int_t liwork, magma_int_t *info)
{
/*  -- MAGMA (version 1.4.0) --
       Univ. of Tennessee, Knoxville
       Univ. of California, Berkeley
       Univ. of Colorado, Denver
       August 2013

    Purpose
    =======
    SSYGVDX_2STAGE computes all the eigenvalues, and optionally, the eigenvectors
    of a complex generalized Hermitian-definite eigenproblem, of the form
    A*x=(lambda)*B*x,  A*Bx=(lambda)*x,  or B*A*x=(lambda)*x.  Here A and
    B are assumed to be Hermitian and B is also positive definite.
    It uses a two-stage algorithm for the tridiagonalization.
    If eigenvectors are desired, it uses a divide and conquer algorithm.

    The divide and conquer algorithm makes very mild assumptions about
    floating point arithmetic. It will work on machines with a guard
    digit in add/subtract, or on those binary machines without guard
    digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or
    Cray-2. It could conceivably fail on hexadecimal or decimal machines
    without guard digits, but we know of none.

    Arguments
    =========
    ITYPE   (input) INTEGER
            Specifies the problem type to be solved:
            = 1:  A*x = (lambda)*B*x
            = 2:  A*B*x = (lambda)*x
            = 3:  B*A*x = (lambda)*x

    RANGE   (input) CHARACTER*1
            = 'A': all eigenvalues will be found.
            = 'V': all eigenvalues in the half-open interval (VL,VU]
                   will be found.
            = 'I': the IL-th through IU-th eigenvalues will be found.

    JOBZ    (input) CHARACTER*1
            = 'N':  Compute eigenvalues only;
            = 'V':  Compute eigenvalues and eigenvectors.

    UPLO    (input) CHARACTER*1
            = 'U':  Upper triangles of A and B are stored;
            = 'L':  Lower triangles of A and B are stored.

    N       (input) INTEGER
            The order of the matrices A and B.  N >= 0.

    A       (input/output) DOUBLE PRECISION array, dimension (LDA, N)
            On entry, the Hermitian matrix A.  If UPLO = 'U', the
            leading N-by-N upper triangular part of A contains the
            upper triangular part of the matrix A.  If UPLO = 'L',
            the leading N-by-N lower triangular part of A contains
            the lower triangular part of the matrix A.

            On exit, if JOBZ = 'V', then if INFO = 0, A contains the
            matrix Z of eigenvectors.  The eigenvectors are normalized
            as follows:
            if ITYPE = 1 or 2, Z**H*B*Z = I;
            if ITYPE = 3, Z**H*inv(B)*Z = I.
            If JOBZ = 'N', then on exit the upper triangle (if UPLO='U')
            or the lower triangle (if UPLO='L') of A, including the
            diagonal, is destroyed.

    LDA     (input) INTEGER
            The leading dimension of the array A.  LDA >= max(1,N).

    B       (input/output) DOUBLE PRECISION array, dimension (LDB, N)
            On entry, the Hermitian matrix B.  If UPLO = 'U', the
            leading N-by-N upper triangular part of B contains the
            upper triangular part of the matrix B.  If UPLO = 'L',
            the leading N-by-N lower triangular part of B contains
            the lower triangular part of the matrix B.

            On exit, if INFO <= N, the part of B containing the matrix is
            overwritten by the triangular factor U or L from the Cholesky
            factorization B = U**H*U or B = L*L**H.

    LDB     (input) INTEGER
            The leading dimension of the array B.  LDB >= max(1,N).

    VL      (input) DOUBLE PRECISION
    VU      (input) DOUBLE PRECISION
            If RANGE='V', the lower and upper bounds of the interval to
            be searched for eigenvalues. VL < VU.
            Not referenced if RANGE = 'A' or 'I'.

    IL      (input) INTEGER
    IU      (input) INTEGER
            If RANGE='I', the indices (in ascending order) of the
            smallest and largest eigenvalues to be returned.
            1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0.
            Not referenced if RANGE = 'A' or 'V'.

    M       (output) INTEGER
            The total number of eigenvalues found.  0 <= M <= N.
            If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.

    W       (output) DOUBLE PRECISION array, dimension (N)
            If INFO = 0, the eigenvalues in ascending order.

    WORK    (workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK))
            On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

    LWORK   (input) INTEGER
            The length of the array WORK.
            If N <= 1,                LWORK >= 1.
            If JOBZ  = 'N' and N > 1, LWORK >= LQ2 + N * (NB + 2).
            If JOBZ  = 'V' and N > 1, LWORK >= LQ2 + 1 + 6*N + 2*N**2.
                                      where LQ2 is the size needed to store
                                      the Q2 matrix and is returned by
                                      MAGMA_BULGE_GET_LQ2.

            If LWORK = -1, then a workspace query is assumed; the routine
            only calculates the optimal sizes of the WORK, RWORK and
            IWORK arrays, returns these values as the first entries of
            the WORK, RWORK and IWORK arrays, and no error message
            related to LWORK or LRWORK or LIWORK is issued by XERBLA.

    IWORK   (workspace/output) INTEGER array, dimension (MAX(1,LIWORK))
            On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK.

    LIWORK  (input) INTEGER
            The dimension of the array IWORK.
            If N <= 1,                LIWORK >= 1.
            If JOBZ  = 'N' and N > 1, LIWORK >= 1.
            If JOBZ  = 'V' and N > 1, LIWORK >= 3 + 5*N.

            If LIWORK = -1, then a workspace query is assumed; the
            routine only calculates the optimal sizes of the WORK, RWORK
            and IWORK arrays, returns these values as the first entries
            of the WORK, RWORK and IWORK arrays, and no error message
            related to LWORK or LRWORK or LIWORK is issued by XERBLA.

    INFO    (output) INTEGER
            = 0:  successful exit
            < 0:  if INFO = -i, the i-th argument had an illegal value
            > 0:  ZPOTRF or ZHEEVD returned an error code:
               <= N:  if INFO = i and JOBZ = 'N', then the algorithm
                      failed to converge; i off-diagonal elements of an
                      intermediate tridiagonal form did not converge to
                      zero;
                      if INFO = i and JOBZ = 'V', then the algorithm
                      failed to compute an eigenvalue while working on
                      the submatrix lying in rows and columns INFO/(N+1)
                      through mod(INFO,N+1);
               > N:   if INFO = N + i, for 1 <= i <= N, then the leading
                      minor of order i of B is not positive definite.
                      The factorization of B could not be completed and
                      no eigenvalues or eigenvectors were computed.

    Further Details
    ===============
    Based on contributions by
       Mark Fahey, Department of Mathematics, Univ. of Kentucky, USA

    Modified so that no backsubstitution is performed if ZHEEVD fails to
    converge (NEIG in old code could be greater than N causing out of
    bounds reference to A - reported by Ralf Meyer).  Also corrected the
    description of INFO and the test on ITYPE. Sven, 16 Feb 05.
    =====================================================================  */

    char uplo_[2] = {uplo, 0};
    char jobz_[2] = {jobz, 0};
    char range_[2] = {range, 0};

    float d_one = MAGMA_S_ONE;

    float *da;
    float *db;
    magma_int_t ldda = n;
    magma_int_t lddb = n;

    magma_int_t lower;
    char trans[1];
    magma_int_t wantz;
    magma_int_t lquery;
    magma_int_t alleig, valeig, indeig;

    magma_int_t lwmin;
    magma_int_t liwmin;

    magma_queue_t stream;
    magma_queue_create( &stream );

    /* determine the number of threads */
    magma_int_t threads = magma_get_numthreads();
    magma_setlapack_numthreads(threads);

    wantz = lapackf77_lsame(jobz_, MagmaVecStr);
    lower = lapackf77_lsame(uplo_, MagmaLowerStr);
    alleig = lapackf77_lsame(range_, "A");
    valeig = lapackf77_lsame(range_, "V");
    indeig = lapackf77_lsame(range_, "I");
    lquery = lwork == -1 || liwork == -1;

    *info = 0;
    if (itype < 1 || itype > 3) {
        *info = -1;
    } else if (! (alleig || valeig || indeig)) {
        *info = -2;
    } else if (! (wantz || lapackf77_lsame(jobz_, MagmaNoVecStr))) {
        *info = -3;
    } else if (! (lower || lapackf77_lsame(uplo_, MagmaUpperStr))) {
        *info = -4;
    } else if (n < 0) {
        *info = -5;
    } else if (lda < max(1,n)) {
        *info = -7;
    } else if (ldb < max(1,n)) {
        *info = -9;
    } else {
        if (valeig) {
            if (n > 0 && vu <= vl) {
                *info = -11;
            }
        } else if (indeig) {
            if (il < 1 || il > max(1,n)) {
                *info = -12;
            } else if (iu < min(n,il) || iu > n) {
                *info = -13;
            }
        }
    }

    magma_int_t nb = magma_get_sbulge_nb(n, threads);
    magma_int_t lq2 = magma_sbulge_get_lq2(n, threads);

    if (wantz) {
        lwmin = lq2 + 1 + 6*n + 2*n*n;
        liwmin = 3 + 5*n;
    } else {
        lwmin = n * (nb + 2);
        liwmin = 1;
    }

    work[0] = lwmin * (1. + lapackf77_slamch("Epsilon"));
    iwork[0] = liwmin;

    if (lwork < lwmin && ! lquery) {
        *info = -17;
    } else if (liwork < liwmin && ! lquery) {
        *info = -19;
    }

    if (*info != 0) {
        magma_xerbla( __func__, -(*info));
        return *info;
    } else if (lquery) {
        return *info;
    }

    /* Quick return if possible */
    if (n == 0) {
        return *info;
    }

    /* Check if matrix is very small then just call LAPACK on CPU, no need for GPU */
    if (n <= 128){
        #ifdef ENABLE_DEBUG
        printf("--------------------------------------------------------------\n");
        printf("  warning matrix too small N=%d NB=%d, calling lapack on CPU  \n", (int) n, (int) nb);
        printf("--------------------------------------------------------------\n");
        #endif
        lapackf77_ssygvd(&itype, jobz_, uplo_,
                         &n, a, &lda, b, &ldb,
                         w, work, &lwork,
                         iwork, &liwork, info);
        *m = n;
        return *info;
    }

    if (MAGMA_SUCCESS != magma_smalloc( &da, n*ldda ) ||
        MAGMA_SUCCESS != magma_smalloc( &db, n*lddb )) {
        *info = MAGMA_ERR_DEVICE_ALLOC;
        return *info;
    }

    /* Form a Cholesky factorization of B. */
    magma_ssetmatrix( n, n, b, ldb, db, lddb );
    magma_ssetmatrix_async( n, n,
                            a,  lda,
                            da, ldda, stream );

#ifdef ENABLE_TIMER
    magma_timestr_t start, end;
    start = get_current_time();
#endif

    magma_spotrf_gpu(uplo_[0], n, db, lddb, info);
    if (*info != 0) {
        *info = n + *info;
        return *info;
    }

#ifdef ENABLE_TIMER
    end = get_current_time();
    printf("time spotrf_gpu = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif

    magma_queue_sync( stream );
    magma_sgetmatrix_async( n, n,
                            db, lddb,
                            b,  ldb, stream );

#ifdef ENABLE_TIMER
    start = get_current_time();
#endif

    /* Transform problem to standard eigenvalue problem and solve. */
    magma_ssygst_gpu(itype, uplo, n, da, ldda, db, lddb, info);

#ifdef ENABLE_TIMER
    end = get_current_time();
    printf("time ssygst_gpu = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif

    magma_sgetmatrix( n, n, da, ldda, a, lda );
    magma_queue_sync( stream );
    magma_free( da );
    magma_free( db );

#ifdef ENABLE_TIMER
    start = get_current_time();
#endif

    magma_ssyevdx_2stage(jobz, range, uplo, n, a, lda, vl, vu, il, iu, m, w, work, lwork, iwork, liwork, info);

#ifdef ENABLE_TIMER
    end = get_current_time();
    printf("time ssyevdx_2stage = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif

    if (wantz && *info == 0) {

        if (MAGMA_SUCCESS != magma_smalloc( &da, n*ldda ) ||
            MAGMA_SUCCESS != magma_smalloc( &db, n*lddb )) {
            *info = MAGMA_ERR_DEVICE_ALLOC;
            return *info;
        }

#ifdef ENABLE_TIMER
        start = get_current_time();
#endif

        magma_ssetmatrix( n, *m, a, lda, da, ldda );
        magma_ssetmatrix( n,  n, b, ldb, db, lddb );

        /* Backtransform eigenvectors to the original problem. */
        if (itype == 1 || itype == 2) {
            /* For A*x=(lambda)*B*x and A*B*x=(lambda)*x;
               backtransform eigenvectors: x = inv(L)'*y or inv(U)*y */
            if (lower) {
                *(unsigned char *)trans = MagmaConjTrans;
            } else {
                *(unsigned char *)trans = MagmaNoTrans;
            }

            magma_strsm(MagmaLeft, uplo, *trans, MagmaNonUnit, n, *m, d_one, db, lddb, da, ldda);
        }
        else if (itype == 3) {
            /* For B*A*x=(lambda)*x;
               backtransform eigenvectors: x = L*y or U'*y */
            if (lower) {
                *(unsigned char *)trans = MagmaNoTrans;
            } else {
                *(unsigned char *)trans = MagmaConjTrans;
            }

            magma_strmm(MagmaLeft, uplo, *trans, MagmaNonUnit, n, *m, d_one, db, lddb, da, ldda);
        }

        magma_sgetmatrix( n, *m, da, ldda, a, lda );

#ifdef ENABLE_TIMER
        end = get_current_time();
        printf("time strsm/mm + getmatrix = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif

        magma_free( da );
        magma_free( db );
    }

    magma_queue_destroy( stream );

    work[0] = lwmin * (1. + lapackf77_slamch("Epsilon"));
    iwork[0] = liwmin;

    return *info;
} /* ssygvdx_2stage */
示例#3
0
extern "C" magma_int_t
magma_ssyevdx_2stage(char jobz, char range, char uplo,
                     magma_int_t n,
                     float *a, magma_int_t lda,
                     float vl, float vu, magma_int_t il, magma_int_t iu,
                     magma_int_t *m, float *w,
                     float *work, magma_int_t lwork,
                     magma_int_t *iwork, magma_int_t liwork,
                     magma_int_t *info)
{
/*  -- MAGMA (version 1.4.1) --
       Univ. of Tennessee, Knoxville
       Univ. of California, Berkeley
       Univ. of Colorado, Denver
       December 2013

    Purpose
    =======
    ZHEEVD_2STAGE computes all eigenvalues and, optionally, eigenvectors of a
    complex Hermitian matrix A. It uses a two-stage algorithm for the tridiagonalization.
    If eigenvectors are desired, it uses a divide and conquer algorithm.

    The divide and conquer algorithm makes very mild assumptions about
    floating point arithmetic. It will work on machines with a guard
    digit in add/subtract, or on those binary machines without guard
    digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or
    Cray-2. It could conceivably fail on hexadecimal or decimal machines
    without guard digits, but we know of none.

    Arguments
    =========
    JOBZ    (input) CHARACTER*1
            = 'N':  Compute eigenvalues only;
            = 'V':  Compute eigenvalues and eigenvectors.

    RANGE   (input) CHARACTER*1
            = 'A': all eigenvalues will be found.
            = 'V': all eigenvalues in the half-open interval (VL,VU]
                   will be found.
            = 'I': the IL-th through IU-th eigenvalues will be found.

    UPLO    (input) CHARACTER*1
            = 'U':  Upper triangle of A is stored;
            = 'L':  Lower triangle of A is stored.

    N       (input) INTEGER
            The order of the matrix A.  N >= 0.

    A       (input/output) COMPLEX_16 array, dimension (LDA, N)
            On entry, the Hermitian matrix A.  If UPLO = 'U', the
            leading N-by-N upper triangular part of A contains the
            upper triangular part of the matrix A.  If UPLO = 'L',
            the leading N-by-N lower triangular part of A contains
            the lower triangular part of the matrix A.
            On exit, if JOBZ = 'V', then if INFO = 0, the first m columns
            of A contains the required
            orthonormal eigenvectors of the matrix A.
            If JOBZ = 'N', then on exit the lower triangle (if UPLO='L')
            or the upper triangle (if UPLO='U') of A, including the
            diagonal, is destroyed.

    LDA     (input) INTEGER
            The leading dimension of the array A.  LDA >= max(1,N).

    VL      (input) REAL
    VU      (input) REAL
            If RANGE='V', the lower and upper bounds of the interval to
            be searched for eigenvalues. VL < VU.
            Not referenced if RANGE = 'A' or 'I'.

    IL      (input) INTEGER
    IU      (input) INTEGER
            If RANGE='I', the indices (in ascending order) of the
            smallest and largest eigenvalues to be returned.
            1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0.
            Not referenced if RANGE = 'A' or 'V'.

    M       (output) INTEGER
            The total number of eigenvalues found.  0 <= M <= N.
            If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.

    W       (output) REAL array, dimension (N)
            If INFO = 0, the required m eigenvalues in ascending order.

    WORK    (workspace/output) COMPLEX_16 array, dimension (MAX(1,LWORK))
            On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

    LWORK   (input) INTEGER
            The length of the array WORK.
            If N <= 1,                LWORK >= 1.
            If JOBZ  = 'N' and N > 1, LWORK >= LQ2 + N * (NB + 2).
            If JOBZ  = 'V' and N > 1, LWORK >= LQ2 + 1 + 6*N + 2*N**2.
                                      where LQ2 is the size needed to store
                                      the Q2 matrix and is returned by
                                      MAGMA_BULGE_GET_LQ2.

            If LWORK = -1, then a workspace query is assumed; the routine
            only calculates the optimal sizes of the WORK, RWORK and
            IWORK arrays, returns these values as the first entries of
            the WORK, RWORK and IWORK arrays, and no error message
            related to LWORK or LRWORK or LIWORK is issued by XERBLA.

    IWORK   (workspace/output) INTEGER array, dimension (MAX(1,LIWORK))
            On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK.

    LIWORK  (input) INTEGER
            The dimension of the array IWORK.
            If N <= 1,                LIWORK >= 1.
            If JOBZ  = 'N' and N > 1, LIWORK >= 1.
            If JOBZ  = 'V' and N > 1, LIWORK >= 3 + 5*N.

            If LIWORK = -1, then a workspace query is assumed; the
            routine only calculates the optimal sizes of the WORK, RWORK
            and IWORK arrays, returns these values as the first entries
            of the WORK, RWORK and IWORK arrays, and no error message
            related to LWORK or LRWORK or LIWORK is issued by XERBLA.

    INFO    (output) INTEGER
            = 0:  successful exit
            < 0:  if INFO = -i, the i-th argument had an illegal value
            > 0:  if INFO = i and JOBZ = 'N', then the algorithm failed
                  to converge; i off-diagonal elements of an intermediate
                  tridiagonal form did not converge to zero;
                  if INFO = i and JOBZ = 'V', then the algorithm failed
                  to compute an eigenvalue while working on the submatrix
                  lying in rows and columns INFO/(N+1) through
                  mod(INFO,N+1).

    Further Details
    ===============
    Based on contributions by
       Jeff Rutter, Computer Science Division, University of California
       at Berkeley, USA

    Modified description of INFO. Sven, 16 Feb 05.
    =====================================================================   */

    char uplo_[2] = {uplo, 0};
    char jobz_[2] = {jobz, 0};
    char range_[2] = {range, 0};
    float d_one  = 1.;
    magma_int_t ione = 1;
    magma_int_t izero = 0;

    float d__1;

    float eps;
    float anrm;
    magma_int_t imax;
    float rmin, rmax;
    float sigma;
    magma_int_t lwmin, liwmin;
    magma_int_t lower;
    magma_int_t wantz;
    magma_int_t iscale;
    float safmin;
    float bignum;
    float smlnum;
    magma_int_t lquery;
    magma_int_t alleig, valeig, indeig;

    float* dwork;

    /* determine the number of threads */
    magma_int_t threads = magma_get_numthreads();
    magma_setlapack_numthreads(threads);

    wantz = lapackf77_lsame(jobz_, MagmaVecStr);
    lower = lapackf77_lsame(uplo_, MagmaLowerStr);

    alleig = lapackf77_lsame( range_, "A" );
    valeig = lapackf77_lsame( range_, "V" );
    indeig = lapackf77_lsame( range_, "I" );

    lquery = lwork == -1 || liwork == -1;

    *info = 0;
    if (! (wantz || lapackf77_lsame(jobz_, MagmaNoVecStr))) {
        *info = -1;
    } else if (! (alleig || valeig || indeig)) {
        *info = -2;
    } else if (! (lower || lapackf77_lsame(uplo_, MagmaUpperStr))) {
        *info = -3;
    } else if (n < 0) {
        *info = -4;
    } else if (lda < max(1,n)) {
        *info = -6;
    } else {
        if (valeig) {
            if (n > 0 && vu <= vl) {
                *info = -8;
            }
        } else if (indeig) {
            if (il < 1 || il > max(1,n)) {
                *info = -9;
            } else if (iu < min(n,il) || iu > n) {
                *info = -10;
            }
        }
    }

    magma_int_t nb = magma_get_sbulge_nb(n, threads);
    magma_int_t Vblksiz = magma_sbulge_get_Vblksiz(n, nb, threads);

    magma_int_t ldt = Vblksiz;
    magma_int_t ldv = nb + Vblksiz;
    magma_int_t blkcnt = magma_bulge_get_blkcnt(n, nb, Vblksiz);
    magma_int_t lq2 = magma_sbulge_get_lq2(n, threads);

    if (wantz) {
        lwmin = lq2 + 1 + 6 * n + 2 * n * n;
        liwmin = 5 * n + 3;
    } else {
        lwmin = lq2 + n * (nb + 1);
        liwmin = 1;
    }

    work[0] = lwmin * (1. + lapackf77_slamch("Epsilon"));
    iwork[0] = liwmin;

    if ((lwork < lwmin) && !lquery) {
        *info = -14;
    } else if ((liwork < liwmin) && ! lquery) {
        *info = -16;
    }

    if (*info != 0) {
        magma_xerbla( __func__, -(*info) );
        return *info;
    }
    else if (lquery) {
        return *info;
    }
    /* Quick return if possible */
    if (n == 0) {
        return *info;
    }

    if (n == 1) {
        w[0] = a[0];
        if (wantz) {
            a[0] = MAGMA_S_ONE;
        }
        return *info;
    }

#ifdef ENABLE_TIMER
    printf("using %d threads\n", threads);
#endif
    /* Check if matrix is very small then just call LAPACK on CPU, no need for GPU */
    magma_int_t ntiles = n/nb;
    if( ( ntiles < 2 ) || ( n <= 128 ) ){
        #ifdef ENABLE_DEBUG
        printf("--------------------------------------------------------------\n");
        printf("  warning matrix too small N=%d NB=%d, calling lapack on CPU  \n", (int) n, (int ) nb);
        printf("--------------------------------------------------------------\n");
        #endif
        lapackf77_ssyevd(jobz_, uplo_, &n, 
                        a, &lda, w, 
                        work, &lwork, 
                        iwork, &liwork, 
                        info);
        *m = n; 
        return *info;
    }

    /* Get machine constants. */
    safmin = lapackf77_slamch("Safe minimum");
    eps = lapackf77_slamch("Precision");
    smlnum = safmin / eps;
    bignum = 1. / smlnum;
    rmin = magma_ssqrt(smlnum);
    rmax = magma_ssqrt(bignum);

    /* Scale matrix to allowable range, if necessary. */
    anrm = lapackf77_slansy("M", uplo_, &n, a, &lda, work);
    iscale = 0;
    if (anrm > 0. && anrm < rmin) {
        iscale = 1;
        sigma = rmin / anrm;
    } else if (anrm > rmax) {
        iscale = 1;
        sigma = rmax / anrm;
    }
    if (iscale == 1) {
        lapackf77_slascl(uplo_, &izero, &izero, &d_one, &sigma, &n, &n, a,
                         &lda, info);
    }

    magma_int_t inde    = 0;
    magma_int_t indT2   = inde + n;
    magma_int_t indTAU2 = indT2  + blkcnt*ldt*Vblksiz;
    magma_int_t indV2   = indTAU2+ blkcnt*Vblksiz;
    magma_int_t indtau1 = indV2  + blkcnt*ldv*Vblksiz;
    magma_int_t indwrk  = indtau1+ n;
    magma_int_t indwk2  = indwrk + n * n;

    magma_int_t llwork = lwork - indwrk;
    magma_int_t llwrk2 = lwork - indwk2;

#ifdef ENABLE_TIMER
    magma_timestr_t start, st1, st2, end;
    start = get_current_time();
#endif

    float *dT1;

    if (MAGMA_SUCCESS != magma_smalloc( &dT1, n*nb)) {
        *info = MAGMA_ERR_DEVICE_ALLOC;
        return *info;
    }

    magma_ssytrd_sy2sb(uplo, n, nb, a, lda, &work[indtau1], &work[indwrk], llwork, dT1, threads, info);

#ifdef ENABLE_TIMER
    st1 = get_current_time();
    printf("  time ssytrd_sy2sb = %6.2f\n" , GetTimerValue(start,st1)/1000.);
#endif

    /* copy the input matrix into WORK(INDWRK) with band storage */
    /* PAY ATTENTION THAT work[indwrk] should be able to be of size lda2*n which it should be checked in any future modification of lwork.*/
    magma_int_t lda2 = 2*nb; //nb+1+(nb-1);
    float* A2 = &work[indwrk];
    memset(A2 , 0, n*lda2*sizeof(float));

    for (magma_int_t j = 0; j < n-nb; j++)
    {
        cblas_scopy(nb+1, &a[j*(lda+1)], 1, &A2[j*lda2], 1);
        memset(&a[j*(lda+1)], 0, (nb+1)*sizeof(float));
        a[nb + j*(lda+1)] = d_one;
    }
    for (magma_int_t j = 0; j < nb; j++)
    {
        cblas_scopy(nb-j, &a[(j+n-nb)*(lda+1)], 1, &A2[(j+n-nb)*lda2], 1);
        memset(&a[(j+n-nb)*(lda+1)], 0, (nb-j)*sizeof(float));
    }

#ifdef ENABLE_TIMER
    st2 = get_current_time();
    printf("  time ssytrd_convert = %6.2f\n" , GetTimerValue(st1,st2)/1000.);
#endif

    magma_ssytrd_sb2st(threads, uplo, n, nb, Vblksiz, A2, lda2, w, &work[inde], &work[indV2], ldv, &work[indTAU2], wantz, &work[indT2], ldt);

#ifdef ENABLE_TIMER
    end = get_current_time();
    printf("  time ssytrd_sy2st = %6.2f\n" , GetTimerValue(st2,end)/1000.);
    printf("  time ssytrd = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif

    /* For eigenvalues only, call SSTERF.  For eigenvectors, first call
     ZSTEDC to generate the eigenvector matrix, WORK(INDWRK), of the
     tridiagonal matrix, then call ZUNMTR to multiply it to the Householder
     transformations represented as Householder vectors in A. */
    if (! wantz) {
#ifdef ENABLE_TIMER
        start = get_current_time();
#endif

        lapackf77_ssterf(&n, w, &work[inde], info);
        magma_smove_eig(range, n, w, &il, &iu, vl, vu, m);

#ifdef ENABLE_TIMER
        end = get_current_time();
        printf("  time sstedc = %6.2f\n", GetTimerValue(start,end)/1000.);
#endif
    } else {

#ifdef ENABLE_TIMER
        start = get_current_time();
#endif

        if (MAGMA_SUCCESS != magma_smalloc( &dwork, 3*n*(n/2 + 1) )) {
            *info = MAGMA_ERR_DEVICE_ALLOC;
            return *info;
        }

        magma_sstedx(range, n, vl, vu, il, iu, w, &work[inde],
                     &work[indwrk], n, &work[indwk2],
                     llwrk2, iwork, liwork, dwork, info);

        magma_free( dwork );

#ifdef ENABLE_TIMER
        end = get_current_time();
        printf("  time sstedx = %6.2f\n", GetTimerValue(start,end)/1000.);
        start = get_current_time();
#endif
        float *dZ;
        magma_int_t lddz = n;

        float *da;
        magma_int_t ldda = n;

        magma_smove_eig(range, n, w, &il, &iu, vl, vu, m);

        if (MAGMA_SUCCESS != magma_smalloc( &dZ, *m*lddz)) {
            *info = MAGMA_ERR_DEVICE_ALLOC;
            return *info;
        }
        if (MAGMA_SUCCESS != magma_smalloc( &da, n*ldda )) {
            *info = MAGMA_ERR_DEVICE_ALLOC;
            return *info;
        }

        magma_sbulge_back(threads, uplo, n, nb, *m, Vblksiz, &work[indwrk + n * (il-1)], n, dZ, lddz,
                          &work[indV2], ldv, &work[indTAU2], &work[indT2], ldt, info);

#ifdef ENABLE_TIMER
        st1 = get_current_time();

        printf("  time sbulge_back = %6.2f\n" , GetTimerValue(start,st1)/1000.);
#endif

        magma_ssetmatrix( n, n, a, lda, da, ldda );

        magma_sormqr_gpu_2stages(MagmaLeft, MagmaNoTrans, n-nb, *m, n-nb, da+nb, ldda,
                                 dZ+nb, n, dT1, nb, info);

        magma_sgetmatrix( n, *m, dZ, lddz, a, lda );
        magma_free(dT1);
        magma_free(dZ);
        magma_free(da);

#ifdef ENABLE_TIMER
        end = get_current_time();
        printf("  time sormqr + copy = %6.2f\n", GetTimerValue(st1,end)/1000.);

        printf("  time eigenvectors backtransf. = %6.2f\n" , GetTimerValue(start,end)/1000.);
#endif

    }

    /* If matrix was scaled, then rescale eigenvalues appropriately. */
    if (iscale == 1) {
        if (*info == 0) {
            imax = n;
        } else {
            imax = *info - 1;
        }
        d__1 = 1. / sigma;
        blasf77_sscal(&imax, &d__1, w, &ione);
    }

    work[0] = lwmin * (1. + lapackf77_slamch("Epsilon"));
    iwork[0] = liwmin;

    return *info;
} /* magma_zheevdx_2stage */
/* ////////////////////////////////////////////////////////////////////////////
   -- Testing ssygvdx
*/
int main( int argc, char** argv)
{

    TESTING_INIT();

    real_Double_t gpu_time;

    float *h_A, *h_R, *h_work;

#if defined(PRECISION_z) || defined(PRECISION_c)
    float *rwork;
    magma_int_t lrwork;
#endif

    /* Matrix size */
    float *w1, *w2;
    magma_int_t *iwork;
    magma_int_t N, n2, info, lwork, liwork;
    magma_int_t ione     = 1;
    magma_int_t ISEED[4] = {0,0,0,1};;
    magma_int_t info_ortho     = 0;
    magma_int_t info_solution  = 0;
    magma_int_t info_reduction = 0;

    magma_timestr_t start, end;

    magma_opts opts;
    parse_opts( argc, argv, &opts );

    magma_int_t ngpu = opts.ngpu;
    char jobz = opts.jobz;
    magma_int_t checkres = opts.check;

    char range = 'A';
    char uplo = opts.uplo;
    magma_int_t itype = opts.itype;
    float f = opts.fraction;

    if (f != 1)
        range='I';

    if ( checkres && jobz == MagmaNoVec ) {
        fprintf( stderr, "checking results requires vectors; setting jobz=V (option -JV)\n" );
        jobz = MagmaVec;
    }

    printf("using: itype = %d, jobz = %c, range = %c, uplo = %c, checkres = %d, fraction = %6.4f\n",
           (int) itype, jobz, range, uplo, (int) checkres, f);

    printf("  N     M     GPU Time(s) \n");
    printf("==========================\n");
    magma_int_t threads = magma_get_numthreads();
    for( magma_int_t i = 0; i < opts.ntest; ++i ) {
        for( magma_int_t iter = 0; iter < opts.niter; ++iter ) {
            N = opts.nsize[i];
            n2     = N*N;
#if defined(PRECISION_z) || defined(PRECISION_c)
            lwork  = magma_sbulge_get_lq2(N, threads) + 2*N + N*N;
            lrwork = 1 + 5*N +2*N*N;
#else
            lwork  = magma_sbulge_get_lq2(N, threads) + 1 + 6*N + 2*N*N;
#endif
            liwork = 3 + 5*N;

            /* Allocate host memory for the matrix */
            TESTING_MALLOC(   h_A, float, n2);
            TESTING_MALLOC(    w1, float         ,  N);
            TESTING_MALLOC(    w2, float         ,  N);
            TESTING_HOSTALLOC(h_R, float, n2);
            TESTING_HOSTALLOC(h_work, float,  lwork);
#if defined(PRECISION_z) || defined(PRECISION_c)
            TESTING_HOSTALLOC( rwork,          float, lrwork);
#endif
            TESTING_MALLOC(    iwork,     magma_int_t, liwork);


            /* Initialize the matrix */
            lapackf77_slarnv( &ione, ISEED, &n2, h_A );
            /* Make diagonal real */
            for(int i=0; i<N; i++) {
                MAGMA_S_SET2REAL( h_A[i*N+i], MAGMA_S_REAL(h_A[i*N+i]) );
            }


            magma_int_t m1 = 0;
            float vl = 0;
            float vu = 0;
            magma_int_t il = 0;
            magma_int_t iu = 0;
            if (range == 'I'){
                il = 1;
                iu = (int) (f*N);
            }

            if(opts.warmup){
                // ==================================================================
                // Warmup using MAGMA
                // ==================================================================
                lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_A, &N, h_R, &N );
                if(ngpu==1){
                    printf("calling ssyevdx_2stage 1 GPU\n");
                    magma_ssyevdx_2stage(jobz, range, uplo, N, 
                                    h_R, N, 
                                    vl, vu, il, iu, 
                                    &m1, w1, 
                                    h_work, lwork, 
#if defined(PRECISION_z) || defined(PRECISION_c)
                                    rwork, lrwork, 
#endif         
                                    iwork, liwork, 
                                    &info);
               
                }else{
                    printf("calling ssyevdx_2stage_m %d GPU\n", (int) ngpu);
                    magma_ssyevdx_2stage_m(ngpu, jobz, range, uplo, N, 
                                    h_R, N, 
                                    vl, vu, il, iu, 
                                    &m1, w1, 
                                    h_work, lwork, 
#if defined(PRECISION_z) || defined(PRECISION_c)
                                    rwork, lrwork, 
#endif         
                                    iwork, liwork, 
                                    &info);
                }
            }


            // ===================================================================
            // Performs operation using MAGMA
            // ===================================================================
            lapackf77_slacpy( MagmaUpperLowerStr, &N, &N, h_A, &N, h_R, &N );
            start = get_current_time();
            if(ngpu==1){
                printf("calling ssyevdx_2stage 1 GPU\n");
                magma_ssyevdx_2stage(jobz, range, uplo, N, 
                                h_R, N, 
                                vl, vu, il, iu, 
                                &m1, w1, 
                                h_work, lwork, 
#if defined(PRECISION_z) || defined(PRECISION_c)
                                rwork, lrwork, 
#endif     
                                iwork, liwork, 
                                &info);
           
            }else{
                printf("calling ssyevdx_2stage_m %d GPU\n", (int) ngpu);
                magma_ssyevdx_2stage_m(ngpu, jobz, range, uplo, N, 
                                h_R, N, 
                                vl, vu, il, iu, 
                                &m1, w1, 
                                h_work, lwork, 
#if defined(PRECISION_z) || defined(PRECISION_c)
                                rwork, lrwork, 
#endif     
                                iwork, liwork, 
                                &info);
            }
            end = get_current_time();
            gpu_time = GetTimerValue(start,end)/1000.;

            if ( checkres ) {
                float eps   = lapackf77_slamch("E");
                printf("\n");
                printf("------ TESTS FOR MAGMA SSYEVD ROUTINE -------  \n");
                printf("        Size of the Matrix %d by %d\n", (int) N, (int) N);
                printf("\n");
                printf(" The matrix A is randomly generated for each test.\n");
                printf("============\n");
                printf(" The relative machine precision (eps) is %8.2e\n",eps);
                printf(" Computational tests pass if scaled residuals are less than 60.\n");
              
                /* Check the orthogonality, reduction and the eigen solutions */
                if (jobz == MagmaVec) {
                    info_ortho = check_orthogonality(N, N, h_R, N, eps);
                    info_reduction = check_reduction(uplo, N, 1, h_A, w1, N, h_R, eps);
                }
                printf("------ CALLING LAPACK SSYEVD TO COMPUTE only eigenvalue and verify elementswise -------  \n");
                lapackf77_ssyevd("N", "L", &N, 
                                h_A, &N, w2, 
                                h_work, &lwork, 
#if defined(PRECISION_z) || defined(PRECISION_c)
                                rwork, &lrwork, 
#endif     
                                iwork, &liwork, 
                                &info);
                info_solution = check_solution(N, w2, w1, eps);
              
                if ( (info_solution == 0) & (info_ortho == 0) & (info_reduction == 0) ) {
                    printf("***************************************************\n");
                    printf(" ---- TESTING SSYEVD ...................... PASSED !\n");
                    printf("***************************************************\n");
                }
                else {
                    printf("************************************************\n");
                    printf(" - TESTING SSYEVD ... FAILED !\n");
                    printf("************************************************\n");
                }
            }


            /* =====================================================================
             Print execution time
             =================================================================== */
            printf("%5d %5d     %6.2f\n",
                   (int) N, (int) m1, gpu_time);

            TESTING_FREE(       h_A);
            TESTING_FREE(        w1);
            TESTING_FREE(        w2);
#if defined(PRECISION_z) || defined(PRECISION_c)
            TESTING_HOSTFREE( rwork);
#endif
            TESTING_FREE(     iwork);
            TESTING_HOSTFREE(h_work);
            TESTING_HOSTFREE(   h_R);
        }
        if ( opts.niter > 1 ) {
            printf( "\n" );
        }
    }

    /* Shutdown */
    TESTING_FINALIZE();

    return 0;
}