Esempio n. 1
0
/**
    Purpose
    -------
    SGETRF computes an LU factorization of a general M-by-N matrix A
    using partial pivoting with row interchanges.

    The factorization has the form
        A = P * L * U
    where P is a permutation matrix, L is lower triangular with unit
    diagonal elements (lower trapezoidal if m > n), and U is upper
    triangular (upper trapezoidal if m < n).

    This is the right-looking Level 3 BLAS version of the algorithm.

    This is a batched version that factors batchCount M-by-N matrices in parallel.
    dA, ipiv, and info become arrays with one entry per matrix.

    Arguments
    ---------
    @param[in]
    m       INTEGER
            The number of rows of each matrix A.  M >= 0.

    @param[in]
    n       INTEGER
            The number of columns of each matrix A.  N >= 0.

    @param[in,out]
    dA_array    Array of pointers, dimension (batchCount).
            Each is a REAL array on the GPU, dimension (LDDA,N).
            On entry, each pointer is an M-by-N matrix to be factored.
            On exit, the factors L and U from the factorization
            A = P*L*U; the unit diagonal elements of L are not stored.

    @param[in]
    ldda    INTEGER
            The leading dimension of each array A.  LDDA >= max(1,M).

    @param[out]
    ipiv_array  Array of pointers, dimension (batchCount), for corresponding matrices.
            Each is an INTEGER array, dimension (min(M,N))
            The pivot indices; for 1 <= i <= min(M,N), row i of the
            matrix was interchanged with row IPIV(i).

    @param[out]
    info_array  Array of INTEGERs, dimension (batchCount), for corresponding matrices.
      -     = 0:  successful exit
      -     < 0:  if INFO = -i, the i-th argument had an illegal value
                  or another error occured, such as memory allocation failed.
      -     > 0:  if INFO = i, U(i,i) is exactly zero. The factorization
                  has been completed, but the factor U is exactly
                  singular, and division by zero will occur if it is used
                  to solve a system of equations.

    @param[in]
    batchCount  INTEGER
                The number of matrices to operate on.

    @param[in]
    queue   magma_queue_t
            Queue to execute in.

    @ingroup magma_sgesv_comp
    ********************************************************************/
extern "C" magma_int_t
magma_sgetrf_batched(
        magma_int_t m, magma_int_t n,
        float **dA_array, 
        magma_int_t ldda,
        magma_int_t **ipiv_array, 
        magma_int_t *info_array, 
        magma_int_t batchCount, magma_queue_t queue)
{
#define A(i_, j_)  (A + (i_) + (j_)*ldda)   

    magma_int_t min_mn = min(m, n);
    cudaMemset(info_array, 0, batchCount*sizeof(magma_int_t));

    /* Check arguments */
    magma_int_t arginfo = 0;
    if (m < 0)
        arginfo = -1;
    else if (n < 0)
        arginfo = -2;
    else if (ldda < max(1,m))
        arginfo = -4;

    if (arginfo != 0) {
        magma_xerbla( __func__, -(arginfo) );
        return arginfo;
    }

    /* Quick return if possible */
    if (m == 0 || n == 0)
        if (min_mn == 0 ) return arginfo;

    if ( m >  2048 || n > 2048 ) {
        #ifndef MAGMA_NOWARNING
        printf("=========================================================================================\n");
        printf("   WARNING batched routines are designed for small sizes it might be better to use the\n   Native/Hybrid classical routines if you want performance\n");
        printf("=========================================================================================\n");
        #endif
    }


//#define ENABLE_TIMER3

#if defined(ENABLE_TIMER3)
    real_Double_t   tall=0.0, tloop=0., talloc=0., tdalloc=0.;
    tall   = magma_sync_wtime(queue);
    talloc = magma_sync_wtime(queue);
#endif

    float c_neg_one = MAGMA_S_NEG_ONE;
    float c_one     = MAGMA_S_ONE;
    magma_int_t nb, recnb, ib, i, k, pm, use_stream;
    magma_get_sgetrf_batched_nbparam(n, &nb, &recnb);

    magma_int_t     **dipiv_displ   = NULL;
    float **dA_displ   = NULL;
    float **dW0_displ  = NULL;
    float **dW1_displ  = NULL;
    float **dW2_displ  = NULL;
    float **dW3_displ  = NULL;
    float **dW4_displ  = NULL;
    float **dinvA_array = NULL;
    float **dwork_array = NULL;


    magma_malloc((void**)&dipiv_displ,   batchCount * sizeof(*dipiv_displ));
    magma_malloc((void**)&dA_displ,   batchCount * sizeof(*dA_displ));
    magma_malloc((void**)&dW0_displ,  batchCount * sizeof(*dW0_displ));
    magma_malloc((void**)&dW1_displ,  batchCount * sizeof(*dW1_displ));
    magma_malloc((void**)&dW2_displ,  batchCount * sizeof(*dW2_displ));
    magma_malloc((void**)&dW3_displ,  batchCount * sizeof(*dW3_displ));
    magma_malloc((void**)&dW4_displ,  batchCount * sizeof(*dW4_displ));
    magma_malloc((void**)&dinvA_array, batchCount * sizeof(*dinvA_array));
    magma_malloc((void**)&dwork_array, batchCount * sizeof(*dwork_array));


    magma_int_t invA_msize = magma_roundup( n, TRI_NB )*TRI_NB;
    magma_int_t dwork_msize = n*nb;
    magma_int_t **pivinfo_array    = NULL;
    magma_int_t *pivinfo           = NULL; 
    float* dinvA      = NULL;
    float* dwork      = NULL; // dinvA and dwork are workspace in strsm
    float **cpuAarray = NULL;
    magma_smalloc( &dinvA, invA_msize * batchCount);
    magma_smalloc( &dwork, dwork_msize * batchCount );
    magma_malloc((void**)&pivinfo_array, batchCount * sizeof(*pivinfo_array));
    magma_malloc((void**)&pivinfo, batchCount * m * sizeof(magma_int_t));
    magma_malloc_cpu((void**) &cpuAarray, batchCount*sizeof(float*));

   /* check allocation */
    if ( dA_displ  == NULL || dW0_displ == NULL || dW1_displ   == NULL || dW2_displ   == NULL || 
         dW3_displ == NULL || dW4_displ == NULL || dinvA_array == NULL || dwork_array == NULL || 
         dinvA     == NULL || dwork     == NULL || cpuAarray   == NULL || 
         dipiv_displ == NULL || pivinfo_array == NULL || pivinfo == NULL) {
        magma_free(dA_displ);
        magma_free(dW0_displ);
        magma_free(dW1_displ);
        magma_free(dW2_displ);
        magma_free(dW3_displ);
        magma_free(dW4_displ);
        magma_free(dinvA_array);
        magma_free(dwork_array);
        magma_free( dinvA );
        magma_free( dwork );
        magma_free_cpu(cpuAarray);
        magma_free(dipiv_displ);
        magma_free(pivinfo_array);
        magma_free(pivinfo);
        magma_int_t info = MAGMA_ERR_DEVICE_ALLOC;
        magma_xerbla( __func__, -(info) );
        return info;
    }


    magmablas_slaset_q( MagmaFull, invA_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dinvA, invA_msize, queue );
    magmablas_slaset_q( MagmaFull, dwork_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dwork, dwork_msize, queue );
    magma_sset_pointer( dwork_array, dwork, 1, 0, 0, dwork_msize, batchCount, queue );
    magma_sset_pointer( dinvA_array, dinvA, TRI_NB, 0, 0, invA_msize, batchCount, queue );
    magma_iset_pointer( pivinfo_array, pivinfo, 1, 0, 0, m, batchCount, queue );

    magma_int_t streamid;
    const magma_int_t nbstreams=10;
    magma_queue_t queues[nbstreams];
    for (i=0; i < nbstreams; i++) {
        magma_device_t cdev;
        magma_getdevice( &cdev );
        magma_queue_create( cdev, &queues[i] );
    }
    magma_getvector( batchCount, sizeof(float*), dA_array, 1, cpuAarray, 1, queue);



#if defined(ENABLE_TIMER3)
    printf(" I am after malloc\n");
    talloc = magma_sync_wtime(queue) - talloc;
    tloop  = magma_sync_wtime(queue);
#endif


    for (i = 0; i < min_mn; i += nb) 
    {
        ib = min(nb, min_mn-i);
        pm = m-i;
        magma_idisplace_pointers(dipiv_displ, ipiv_array, ldda, i, 0, batchCount, queue);
        magma_sdisplace_pointers(dA_displ, dA_array, ldda, i, i, batchCount, queue);
        //===============================================
        //  panel factorization
        //===============================================
        if (recnb == nb)
        {
            arginfo = magma_sgetf2_batched(
                    pm, ib,
                    dA_displ, ldda,
                    dW1_displ, dW2_displ, dW3_displ,
                    dipiv_displ, 
                    info_array, i, batchCount, queue);   
        }
        else {
            arginfo = magma_sgetrf_recpanel_batched(
                    pm, ib, recnb,
                    dA_displ, ldda,
                    dipiv_displ, pivinfo_array,
                    dwork_array, nb, 
                    dinvA_array, invA_msize, 
                    dW0_displ, dW1_displ, dW2_displ, 
                    dW3_displ, dW4_displ,
                    info_array, i, 
                    batchCount, queue);  
        } 
        if (arginfo != 0 ) goto fin;
        //===============================================
        // end of panel
        //===============================================

#define RUN_ALL
#ifdef RUN_ALL
        // setup pivinfo before adjusting ipiv
        setup_pivinfo_batched(pivinfo_array, dipiv_displ, pm, ib, batchCount, queue);
        adjust_ipiv_batched(dipiv_displ, ib, i, batchCount, queue);

        // stepinit_ipiv(pivinfo_array, pm, batchCount); // for debug and check swap, it create an ipiv


#if 0
        slaswp_batched( i, dA_displ, ldda,
                i, i+ib,
                dipiv_displ, pivinfo_array, batchCount);
#else
        magma_sdisplace_pointers(dA_displ, dA_array, ldda, i, 0, batchCount, queue);
        magma_sdisplace_pointers(dW0_displ, dA_array, ldda, i, 0, batchCount, queue);
        magma_slaswp_rowparallel_batched( i, dA_displ, ldda,
                dW0_displ, ldda,
                i, i+ib,
                pivinfo_array, batchCount, queue );

#endif

        if ( (i + ib) < n)
        {
            // swap right side and trsm     
            magma_sdisplace_pointers(dA_displ, dA_array, ldda, i, i+ib, batchCount, queue);
            magma_sset_pointer( dwork_array, dwork, nb, 0, 0, dwork_msize, batchCount, queue ); // I don't think it is needed Azzam
            magma_slaswp_rowparallel_batched( n-(i+ib), dA_displ, ldda,
                    dwork_array, nb,
                    i, i+ib,
                    pivinfo_array, batchCount, queue );


            magma_sdisplace_pointers(dA_displ, dA_array, ldda, i, i, batchCount, queue);
            magma_sdisplace_pointers(dW0_displ, dA_array, ldda, i, i+ib, batchCount, queue);
            magmablas_strsm_outofplace_batched( MagmaLeft, MagmaLower, MagmaNoTrans, MagmaUnit, 1,
                    ib, n-i-ib,
                    MAGMA_S_ONE,
                    dA_displ,    ldda, // dA
                    dwork_array,  nb, // dB
                    dW0_displ,   ldda, // dX
                    dinvA_array,  invA_msize, 
                    dW1_displ,   dW2_displ, 
                    dW3_displ,   dW4_displ,
                    0, batchCount, queue );


            if ( (i + ib) < m)
            {    
                // if gemm size is > 160 use a streamed classical cublas gemm since it is faster
                // the batched is faster only when M=N <= 160 for K40c
                //-------------------------------------------
                //          USE STREAM  GEMM
                //-------------------------------------------
                use_stream = magma_srecommend_cublas_gemm_stream(MagmaNoTrans, MagmaNoTrans, m-i-ib, n-i-ib, ib);
                if (use_stream)
                { 
                    magma_queue_sync(queue); 
                    for (k=0; k < batchCount; k++)
                    {
                        streamid = k%nbstreams;                                       
                        magma_sgemm( MagmaNoTrans, MagmaNoTrans, 
                                m-i-ib, n-i-ib, ib,
                                c_neg_one, cpuAarray[k] + (i+ib)+i*ldda, ldda, 
                                           cpuAarray[k] + i+(i+ib)*ldda, ldda,
                                c_one,     cpuAarray[k] + (i+ib)+(i+ib)*ldda, ldda, queues[streamid] );
                    }
                    // need to synchronise to be sure that sgetf2 do not start before
                    // finishing the update at least of the next panel
                    // if queue is NULL, no need to sync
                    if ( queue != NULL ) {
                         for (magma_int_t s=0; s < nbstreams; s++)
                             magma_queue_sync(queues[s]);
                     }
                }
                //-------------------------------------------
                //          USE BATCHED GEMM
                //-------------------------------------------
                else
                {
                    magma_sdisplace_pointers(dA_displ, dA_array,  ldda, i+ib,    i, batchCount, queue);
                    magma_sdisplace_pointers(dW1_displ, dA_array, ldda,    i, i+ib, batchCount, queue);
                    magma_sdisplace_pointers(dW2_displ, dA_array, ldda, i+ib, i+ib, batchCount, queue);
                    //printf("caling batched dgemm %d %d %d \n", m-i-ib, n-i-ib, ib);
                    magma_sgemm_batched( MagmaNoTrans, MagmaNoTrans, m-i-ib, n-i-ib, ib, 
                                         c_neg_one, dA_displ,  ldda, 
                                                    dW1_displ, ldda, 
                                         c_one,     dW2_displ, ldda, 
                                         batchCount, queue );
                } // end of batched/streamed gemm
            } // end of  if ( (i + ib) < m) 
        } // end of if ( (i + ib) < n)
#endif
    }// end of for

fin:
    magma_queue_sync(queue);
#if defined(ENABLE_TIMER3)
    tloop   = magma_sync_wtime(queue) - tloop;
    tdalloc = magma_sync_wtime(queue);
#endif
    for (k=0; k < nbstreams; k++) {
        magma_queue_destroy( queues[k] );
    }

    magma_free(dA_displ);
    magma_free(dW0_displ);
    magma_free(dW1_displ);
    magma_free(dW2_displ);
    magma_free(dW3_displ);
    magma_free(dW4_displ);
    magma_free(dinvA_array);
    magma_free(dwork_array);
    magma_free( dinvA );
    magma_free( dwork );
    magma_free_cpu(cpuAarray);
    magma_free(dipiv_displ);
    magma_free(pivinfo_array);
    magma_free(pivinfo);

#if defined(ENABLE_TIMER3)
    tdalloc = magma_sync_wtime(queue) - tdalloc;
    tall = magma_sync_wtime(queue) - tall;
    printf("here is the timing from inside sgetrf_batched talloc: %10.5f  tloop: %10.5f tdalloc: %10.5f tall: %10.5f sum: %10.5f\n", talloc, tloop, tdalloc, tall, talloc+tloop+tdalloc );
#endif
    
    return arginfo;
}
Esempio n. 2
0
/**
    Purpose
    -------
    Solves a system of linear equations
      A * X = B,  A**T * X = B,  or  A**H * X = B
    with a general N-by-N matrix A using the LU factorization computed by SGETRF_GPU.

    Arguments
    ---------
    @param[in]
    trans   magma_trans_t
            Specifies the form of the system of equations:
      -     = MagmaNoTrans:    A    * X = B  (No transpose)
      -     = MagmaTrans:      A**T * X = B  (Transpose)
      -     = MagmaConjTrans:  A**H * X = B  (Conjugate transpose)

    @param[in]
    n       INTEGER
            The order of the matrix A.  N >= 0.

    @param[in]
    nrhs    INTEGER
            The number of right hand sides, i.e., the number of columns
            of the matrix B.  NRHS >= 0.

    @param[in]
    dA      REAL array on the GPU, dimension (LDA,N)
            The factors L and U from the factorization A = P*L*U as computed
            by SGETRF_GPU.

    @param[in]
    ldda    INTEGER
            The leading dimension of the array A.  LDA >= max(1,N).

    @param[in]
    ipiv    INTEGER array, dimension (N)
            The pivot indices from SGETRF; for 1 <= i <= N, row i of the
            matrix was interchanged with row IPIV(i).

    @param[in,out]
    dB      REAL array on the GPU, dimension (LDB,NRHS)
            On entry, the right hand side matrix B.
            On exit, the solution matrix X.

    @param[in]
    lddb    INTEGER
            The leading dimension of the array B.  LDB >= max(1,N).

    @param[out]
    info    INTEGER
      -     = 0:  successful exit
      -     < 0:  if INFO = -i, the i-th argument had an illegal value

    @ingroup magma_sgesv_comp
    ********************************************************************/
extern "C" magma_int_t
magma_sgetrs_batched(
                  magma_trans_t trans, magma_int_t n, magma_int_t nrhs,
                  float **dA_array, magma_int_t ldda,
                  magma_int_t **dipiv_array, 
                  float **dB_array, magma_int_t lddb,
                  magma_int_t batchCount, magma_queue_t queue)
{
    magma_int_t notran = (trans == MagmaNoTrans);
    magma_int_t info = 0;
    if ( (! notran) &&
         (trans != MagmaTrans) &&
         (trans != MagmaConjTrans) ) {
        info = -1;
    } else if (n < 0) {
        info = -2;
    } else if (nrhs < 0) {
        info = -3;
    } else if (ldda < max(1,n)) {
        info = -5;
    } else if (lddb < max(1,n)) {
        info = -8;
    }
    if (info != 0) {
        magma_xerbla( __func__, -(info) );
        return info;
    }

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



    float **dW1_displ  = NULL;
    float **dW2_displ  = NULL;
    float **dW3_displ  = NULL;
    float **dW4_displ  = NULL;
    float **dinvA_array = NULL;
    float **dwork_array = NULL;

    magma_malloc((void**)&dW1_displ,  batchCount * sizeof(*dW1_displ));
    magma_malloc((void**)&dW2_displ,  batchCount * sizeof(*dW2_displ));
    magma_malloc((void**)&dW3_displ,  batchCount * sizeof(*dW3_displ));
    magma_malloc((void**)&dW4_displ,  batchCount * sizeof(*dW4_displ));
    magma_malloc((void**)&dinvA_array, batchCount * sizeof(*dinvA_array));
    magma_malloc((void**)&dwork_array, batchCount * sizeof(*dwork_array));

    magma_int_t invA_msize = ((n+TRI_NB-1)/TRI_NB)*TRI_NB*TRI_NB;
    magma_int_t dwork_msize = n*nrhs;
    float* dinvA      = NULL;
    float* dwork      = NULL;// dinvA and dwork are workspace in strsm
    magma_smalloc( &dinvA, invA_msize * batchCount);
    magma_smalloc( &dwork, dwork_msize * batchCount );
   /* check allocation */
    if ( dW1_displ == NULL || dW2_displ == NULL || dW3_displ   == NULL || dW4_displ   == NULL || 
         dinvA_array == NULL || dwork_array == NULL || dinvA     == NULL || dwork     == NULL ) {
        magma_free(dW1_displ);
        magma_free(dW2_displ);
        magma_free(dW3_displ);
        magma_free(dW4_displ);
        magma_free(dinvA_array);
        magma_free(dwork_array);
        magma_free( dinvA );
        magma_free( dwork );
        info = MAGMA_ERR_DEVICE_ALLOC;
        magma_xerbla( __func__, -(info) );
        return info;
    }

    magmablas_slaset_q(MagmaFull, invA_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dinvA, invA_msize, queue);
    magmablas_slaset_q(MagmaFull, dwork_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dwork, dwork_msize, queue);
    sset_pointer(dwork_array, dwork, n, 0, 0, dwork_msize, batchCount, queue);
    sset_pointer(dinvA_array, dinvA, TRI_NB, 0, 0, invA_msize, batchCount, queue);


    magma_queue_t cstream;
    magmablasGetKernelStream(&cstream);


    if (notran) {
        magma_slaswp_rowserial_batched(nrhs, dB_array, lddb, 1, n, dipiv_array, batchCount, queue);
        // solve dwork = L^-1 * NRHS
        magmablas_strsm_outofplace_batched(MagmaLeft, MagmaLower, MagmaNoTrans, MagmaUnit, 1,
                n, nrhs,
                MAGMA_S_ONE,
                dA_array,       ldda, // dA
                dB_array,      lddb, // dB
                dwork_array,        n, // dX //output
                dinvA_array,  invA_msize, 
                dW1_displ,   dW2_displ, 
                dW3_displ,   dW4_displ,
                1, batchCount, queue);

        // solve X = U^-1 * dwork
        magmablas_strsm_outofplace_batched(MagmaLeft, MagmaUpper, MagmaNoTrans, MagmaNonUnit, 1,
                n, nrhs,
                MAGMA_S_ONE,
                dA_array,       ldda, // dA
                dwork_array,        n, // dB 
                dB_array,   lddb, // dX //output
                dinvA_array,  invA_msize, 
                dW1_displ,   dW2_displ, 
                dW3_displ,   dW4_displ,
                1, batchCount, queue);
    }
    else{
        /* Solve A**T * X = B  or  A**H * X = B. */
        // solve 
        magmablas_strsm_outofplace_batched(MagmaLeft, MagmaUpper, trans, MagmaUnit, 1,
                n, nrhs,
                MAGMA_S_ONE,
                dA_array,       ldda, // dA
                dB_array,      lddb, // dB
                dwork_array,        n, // dX //output
                dinvA_array,  invA_msize, 
                dW1_displ,   dW2_displ, 
                dW3_displ,   dW4_displ,
                1, batchCount, queue);

        // solve 
        magmablas_strsm_outofplace_batched(MagmaLeft, MagmaLower, trans, MagmaNonUnit, 1,
                n, nrhs,
                MAGMA_S_ONE,
                dA_array,       ldda, // dA
                dwork_array,        n, // dB 
                dB_array,   lddb, // dX //output
                dinvA_array,  invA_msize, 
                dW1_displ,   dW2_displ, 
                dW3_displ,   dW4_displ,
                1, batchCount, queue);
        magma_slaswp_rowserial_batched(nrhs, dB_array, lddb, 1, n, dipiv_array, batchCount, queue);
    }




    magma_queue_sync(cstream);

    magma_free(dW1_displ);
    magma_free(dW2_displ);
    magma_free(dW3_displ);
    magma_free(dW4_displ);
    magma_free(dinvA_array);
    magma_free(dwork_array);
    magma_free( dinvA );
    magma_free( dwork );

    
    return info;
}
Esempio n. 3
0
/***************************************************************************//**
    Purpose
    -------
    SPOTRF computes the Cholesky factorization of a real symmetric
    positive definite matrix dA.

    The factorization has the form
        dA = U**H * U,   if UPLO = MagmaUpper, or
        dA = L  * L**H,  if UPLO = MagmaLower,
    where U is an upper triangular matrix and L is lower triangular.

    This is the block version of the algorithm, calling Level 3 BLAS.

    Arguments
    ---------
    @param[in]
    uplo    magma_uplo_t
      -     = MagmaUpper:  Upper triangle of dA is stored;
      -     = MagmaLower:  Lower triangle of dA is stored.

    @param[in]
    n       INTEGER
            The order of the matrix dA.  N >= 0.

    @param[in,out]
    dA_array      Array of pointers, dimension (batchCount).
             Each is a REAL array on the GPU, dimension (LDDA,N)
             On entry, each pointer is a symmetric matrix dA.  
             If UPLO = MagmaUpper, the leading
             N-by-N upper triangular part of dA contains the upper
             triangular part of the matrix dA, and the strictly lower
             triangular part of dA is not referenced.  If UPLO = MagmaLower, the
             leading N-by-N lower triangular part of dA contains the lower
             triangular part of the matrix dA, and the strictly upper
             triangular part of dA is not referenced.
    \n
             On exit, if corresponding entry in info_array = 0, 
             each pointer is the factor U or L from the Cholesky
             factorization dA = U**H * U or dA = L * L**H.

    @param[in]
    ldda     INTEGER
            The leading dimension of each array dA.  LDDA >= max(1,N).
            To benefit from coalescent memory accesses LDDA must be
            divisible by 16.

    @param[out]
    info_array    Array of INTEGERs, dimension (batchCount), for corresponding matrices.
      -     = 0:  successful exit
      -     < 0:  if INFO = -i, the i-th argument had an illegal value
      -     > 0:  if INFO = i, the leading minor of order i is not
                  positive definite, and the factorization could not be
                  completed.
    
    @param[in]
    batchCount  INTEGER
                The number of matrices to operate on.

    @param[in]
    queue   magma_queue_t
            Queue to execute in.

    @ingroup magma_potrf_batched
*******************************************************************************/
extern "C" magma_int_t
magma_spotrf_lg_batched(
    magma_uplo_t uplo, magma_int_t n,
    float **dA_array, magma_int_t ldda,
    magma_int_t *info_array,  magma_int_t batchCount, magma_queue_t queue)
{
    magma_int_t arginfo = 0;

#define A(i_, j_)  (A + (i_) + (j_)*ldda)   
    float d_alpha = -1.0;
    float d_beta  = 1.0;

    if ( n > 2048 ) {
        #ifndef MAGMA_NOWARNING
        printf("=========================================================================================\n"
               "   WARNING batched routines are designed for small sizes. It might be better to use the\n"
               "   Native/Hybrid classical routines if you want good performance.\n"
               "=========================================================================================\n");
        #endif
    }

    magma_int_t j, k, ib, use_stream;
    magma_int_t nb, recnb;
    magma_get_spotrf_batched_nbparam(n, &nb, &recnb);

    float **dA_displ   = NULL;
    float **dW0_displ  = NULL;
    float **dW1_displ  = NULL;
    float **dW2_displ  = NULL;
    float **dW3_displ  = NULL;
    float **dW4_displ  = NULL;
    float **dinvA_array = NULL;
    float **dwork_array = NULL;

    magma_malloc((void**)&dA_displ,   batchCount * sizeof(*dA_displ));
    magma_malloc((void**)&dW0_displ,  batchCount * sizeof(*dW0_displ));
    magma_malloc((void**)&dW1_displ,  batchCount * sizeof(*dW1_displ));
    magma_malloc((void**)&dW2_displ,  batchCount * sizeof(*dW2_displ));
    magma_malloc((void**)&dW3_displ,  batchCount * sizeof(*dW3_displ));
    magma_malloc((void**)&dW4_displ,  batchCount * sizeof(*dW4_displ));
    magma_malloc((void**)&dinvA_array, batchCount * sizeof(*dinvA_array));
    magma_malloc((void**)&dwork_array,    batchCount * sizeof(*dwork_array));

    magma_int_t invA_msize = magma_roundup( n, STRTRI_BATCHED_NB )*STRTRI_BATCHED_NB;
    magma_int_t dwork_msize = n*nb;
    float* dinvA      = NULL;
    float* dwork      = NULL; // dinvA and dwork are workspace in strsm
    float **cpuAarray = NULL;
    magma_smalloc( &dinvA, invA_msize * batchCount);
    magma_smalloc( &dwork, dwork_msize * batchCount );
    magma_malloc_cpu((void**) &cpuAarray, batchCount*sizeof(float*));
   /* check allocation */
    if ( dA_displ  == NULL || dW0_displ == NULL || dW1_displ   == NULL || dW2_displ   == NULL || 
         dW3_displ == NULL || dW4_displ == NULL || dinvA_array == NULL || dwork_array == NULL || 
         dinvA     == NULL || dwork     == NULL || cpuAarray   == NULL ) {
        magma_free(dA_displ);
        magma_free(dW0_displ);
        magma_free(dW1_displ);
        magma_free(dW2_displ);
        magma_free(dW3_displ);
        magma_free(dW4_displ);
        magma_free(dinvA_array);
        magma_free(dwork_array);
        magma_free( dinvA );
        magma_free( dwork );
        magma_free_cpu(cpuAarray);
        magma_int_t info = MAGMA_ERR_DEVICE_ALLOC;
        magma_xerbla( __func__, -(info) );
        return info;
    }
    magmablas_slaset_q( MagmaFull, invA_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dinvA, invA_msize, queue );
    magmablas_slaset_q( MagmaFull, dwork_msize, batchCount, MAGMA_S_ZERO, MAGMA_S_ZERO, dwork, dwork_msize, queue );
    magma_sset_pointer( dwork_array, dwork, 1, 0, 0, dwork_msize, batchCount, queue );
    magma_sset_pointer( dinvA_array, dinvA, STRTRI_BATCHED_NB, 0, 0, invA_msize, batchCount, queue );


    magma_int_t streamid;
    const magma_int_t nbstreams=10;
    magma_queue_t queues[nbstreams];
    for (k=0; k < nbstreams; k++) {
        magma_device_t cdev;
        magma_getdevice( &cdev );
        magma_queue_create( cdev, &queues[k] );
    }
    magma_getvector( batchCount, sizeof(float*), dA_array, 1, cpuAarray, 1, queue);

    if (uplo == MagmaUpper) {
        printf("Upper side is unavailable\n");
        goto fin;
    }
    else {
        for (j = 0; j < n; j += nb) {
            ib = min(nb, n-j);
#if 1
            //===============================================
            //  panel factorization
            //===============================================
            magma_sdisplace_pointers(dA_displ, dA_array, ldda, j, j, batchCount, queue);
            magma_sset_pointer( dwork_array, dwork, 1, 0, 0, dwork_msize, batchCount, queue );
            magma_sset_pointer( dinvA_array, dinvA, STRTRI_BATCHED_NB, 0, 0, invA_msize, batchCount, queue );


            if (recnb == nb)
            {
                arginfo = magma_spotrf_panel_batched(
                                   uplo, n-j, ib,
                                   dA_displ, ldda,
                                   dwork_array, dwork_msize,
                                   dinvA_array, invA_msize,
                                   dW0_displ, dW1_displ, dW2_displ,
                                   dW3_displ, dW4_displ,
                                   info_array, j, batchCount, queue);
            }
            else {
                //arginfo = magma_spotrf_rectile_batched(
                arginfo = magma_spotrf_recpanel_batched(
                                   uplo, n-j, ib, recnb,
                                   dA_displ, ldda,
                                   dwork_array, dwork_msize,
                                   dinvA_array, invA_msize,
                                   dW0_displ, dW1_displ, dW2_displ,
                                   dW3_displ, dW4_displ, 
                                   info_array, j, batchCount, queue);
            }
            if (arginfo != 0 ) goto fin;
            //===============================================
            // end of panel
            //===============================================
#endif            
#if 1
            //real_Double_t gpu_time;
            //gpu_time = magma_sync_wtime(queue);
            if ( (n-j-ib) > 0) {
                use_stream = magma_srecommend_cublas_gemm_stream(MagmaNoTrans, MagmaConjTrans, n-j-ib, n-j-ib, ib);
                if (use_stream)
                { 
                    //-------------------------------------------
                    //          USE STREAM  HERK
                    //-------------------------------------------
                    // since it use different queue I need to wait the panel.
                    /* you must know the matrix layout inorder to do it */  
                    magma_queue_sync(queue); 
                    for (k=0; k < batchCount; k++)
                    {
                        streamid = k%nbstreams;                                       
                        // call herk, class ssyrk must call cpu pointer 
                        magma_ssyrk( MagmaLower, MagmaNoTrans, n-j-ib, ib, 
                            d_alpha, 
                            (const float*) cpuAarray[k] + j+ib+j*ldda, ldda, 
                            d_beta,
                            cpuAarray[k] + j+ib+(j+ib)*ldda, ldda, queues[streamid] );
                     }
                     // need to synchronise to be sure that panel do not start before
                     // finishing the update at least of the next panel
                     // if queue is NULL, no need to sync
                     if ( queue != NULL ) {
                         for (magma_int_t s=0; s < nbstreams; s++)
                             magma_queue_sync(queues[s]);
                     }
                }
                else
                {
                    //-------------------------------------------
                    //          USE BATCHED GEMM(which is a HERK in fact, since it only access the lower part)
                    //-------------------------------------------
                    magma_sdisplace_pointers(dA_displ, dA_array, ldda, j+ib, j, batchCount, queue);
                    magma_sdisplace_pointers(dW1_displ, dA_array, ldda, j+ib, j+ib, batchCount, queue);
                    magmablas_ssyrk_batched( uplo, MagmaNoTrans, n-j-ib, ib,
                                          d_alpha, dA_displ, ldda, 
                                          d_beta,  dW1_displ, ldda, 
                                          batchCount, queue );
                }
            } 
            //gpu_time = magma_sync_wtime(queue) - gpu_time;
            //real_Double_t flops = (n-j-ib) * (n-j-ib) * ib / 1e9 * batchCount;
            //real_Double_t gpu_perf = flops / gpu_time;
            //printf("Rows= %lld, Colum=%lld, herk time = %7.2fms, Gflops= %7.2f\n",
            //       (long long)(n-j-ib), (long long) ib, gpu_time*1000, gpu_perf);
#endif
        }
    }

fin:
    magma_queue_sync(queue);
    for (k=0; k < nbstreams; k++) {
        magma_queue_destroy( queues[k] );
    }

    magma_free(dA_displ);
    magma_free(dW0_displ);
    magma_free(dW1_displ);
    magma_free(dW2_displ);
    magma_free(dW3_displ);
    magma_free(dW4_displ);
    magma_free(dinvA_array);
    magma_free(dwork_array);
    magma_free( dinvA );
    magma_free( dwork );
    magma_free_cpu(cpuAarray);

    return arginfo;
}