예제 #1
0
extern "C" magma_int_t
magma_scg_merge(
    magma_s_sparse_matrix A, magma_s_vector b, magma_s_vector *x,  
    magma_s_solver_par *solver_par,
    magma_queue_t queue )
{
    // set queue for old dense routines
    magma_queue_t orig_queue;
    magmablasGetKernelStream( &orig_queue );

    // prepare solver feedback
    solver_par->solver = Magma_CGMERGE;
    solver_par->numiter = 0;
    solver_par->info = MAGMA_SUCCESS; 

    // some useful variables
    float c_zero = MAGMA_S_ZERO, c_one = MAGMA_S_ONE;
    magma_int_t dofs = A.num_rows;

    // GPU stream
    magma_queue_t stream[2];
    magma_event_t event[1];
    magma_queue_create( &stream[0] );
    magma_queue_create( &stream[1] );
    magma_event_create( &event[0] );

    // GPU workspace
    magma_s_vector r, d, z;
    magma_s_vinit( &r, Magma_DEV, dofs, c_zero, queue );
    magma_s_vinit( &d, Magma_DEV, dofs, c_zero, queue );
    magma_s_vinit( &z, Magma_DEV, dofs, c_zero, queue );
    
    float *d1, *d2, *skp;
    d1 = NULL;
    d2 = NULL;
    skp = NULL;
    magma_int_t stat_dev = 0, stat_cpu = 0;
    stat_dev += magma_smalloc( &d1, dofs*(1) );
    stat_dev += magma_smalloc( &d2, dofs*(1) );
    // array for the parameters
    stat_dev += magma_smalloc( &skp, 6 );       
    // skp = [alpha|beta|gamma|rho|tmp1|tmp2]
    if( stat_dev != 0 ){
        magma_free( d1 );
        magma_free( d2 );
        magma_free( skp );
        printf("error: memory allocation.\n");
        return MAGMA_ERR_DEVICE_ALLOC;
    }

    // solver variables
    float alpha, beta, gamma, rho, tmp1, *skp_h;
    float nom, nom0, r0, betanom, den;

    // solver setup
    magma_sscal( dofs, c_zero, x->dval, 1) ;                     // x = 0
    magma_scopy( dofs, b.dval, 1, r.dval, 1 );                    // r = b
    magma_scopy( dofs, b.dval, 1, d.dval, 1 );                    // d = b
    nom0 = betanom = magma_snrm2( dofs, r.dval, 1 );               
    nom = nom0 * nom0;                                           // nom = r' * r
    magma_s_spmv( c_one, A, d, c_zero, z, queue );                      // z = A d
    den = MAGMA_S_REAL( magma_sdot(dofs, d.dval, 1, z.dval, 1) ); // den = d'* z
    solver_par->init_res = nom0;
    
    // array on host for the parameters
    stat_cpu += magma_smalloc_cpu( &skp_h, 6 );
    if( stat_cpu != 0 ){
        magma_free( d1 );
        magma_free( d2 );
        magma_free( skp );
        magma_free_cpu( skp_h );
        printf("error: memory allocation.\n");
        return MAGMA_ERR_HOST_ALLOC;
    }
    
    alpha = rho = gamma = tmp1 = c_one; 
    beta =  magma_sdot(dofs, r.dval, 1, r.dval, 1);
    skp_h[0]=alpha; 
    skp_h[1]=beta; 
    skp_h[2]=gamma; 
    skp_h[3]=rho; 
    skp_h[4]=tmp1; 
    skp_h[5]=MAGMA_S_MAKE(nom, 0.0);

    magma_ssetvector( 6, skp_h, 1, skp, 1 );
    
    if ( (r0 = nom * solver_par->epsilon) < ATOLERANCE ) 
        r0 = ATOLERANCE;
    if ( nom < r0 ) {
        magmablasSetKernelStream( orig_queue );
        return MAGMA_SUCCESS;
    }
    // check positive definite
    if (den <= 0.0) {
        printf("Operator A is not postive definite. (Ar,r) = %f\n", den);
        magmablasSetKernelStream( orig_queue );
        return MAGMA_NONSPD;
        solver_par->info = MAGMA_NONSPD;;
    }
    
    //Chronometry
    real_Double_t tempo1, tempo2;
    tempo1 = magma_sync_wtime( queue );
    if ( solver_par->verbose > 0 ) {
        solver_par->res_vec[0] = (real_Double_t) nom0;
        solver_par->timing[0] = 0.0;
    }
    
    // start iteration
    for( solver_par->numiter= 1; solver_par->numiter<solver_par->maxiter; 
                                                    solver_par->numiter++ ) {

        magmablasSetKernelStream(stream[0]);
        
        // computes SpMV and dot product
        magma_scgmerge_spmv1(  A, d1, d2, d.dval, z.dval, skp, queue ); 
            
        // updates x, r, computes scalars and updates d
        magma_scgmerge_xrbeta( dofs, d1, d2, x->dval, r.dval, d.dval, z.dval, skp, queue ); 

        // check stopping criterion (asynchronous copy)
        magma_sgetvector_async( 1 , skp+1, 1, 
                                                    skp_h+1, 1, stream[1] );
        betanom = sqrt(MAGMA_S_REAL(skp_h[1]));

        if ( solver_par->verbose > 0 ) {
            tempo2 = magma_sync_wtime( queue );
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }

        if (  betanom  < r0 ) {
            break;
        }

    } 
    tempo2 = magma_sync_wtime( queue );
    solver_par->runtime = (real_Double_t) tempo2-tempo1;
    float residual;
    magma_sresidual( A, b, *x, &residual, queue );
    solver_par->iter_res = betanom;
    solver_par->final_res = residual;

    if ( solver_par->numiter < solver_par->maxiter) {
        solver_par->info = MAGMA_SUCCESS;
    } else if ( solver_par->init_res > solver_par->final_res ) {
        if ( solver_par->verbose > 0 ) {
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        solver_par->info = MAGMA_SLOW_CONVERGENCE;
    }
    else {
        if ( solver_par->verbose > 0 ) {
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        solver_par->info = MAGMA_DIVERGENCE;
    }
    magma_s_vfree(&r, queue );
    magma_s_vfree(&z, queue );
    magma_s_vfree(&d, queue );

    magma_free( d1 );
    magma_free( d2 );
    magma_free( skp );
    magma_free_cpu( skp_h );

    magmablasSetKernelStream( orig_queue );
    return MAGMA_SUCCESS;
}   /* magma_scg_merge */
예제 #2
0
magma_int_t
magma_sbicgstab_merge( magma_s_sparse_matrix A, magma_s_vector b, 
        magma_s_vector *x, magma_s_solver_par *solver_par ){

    // prepare solver feedback
    solver_par->solver = Magma_BICGSTABMERGE;
    solver_par->numiter = 0;
    solver_par->info = 0;

    // some useful variables
    float c_zero = MAGMA_S_ZERO, c_one = MAGMA_S_ONE;
    
    magma_int_t dofs = A.num_rows;

    // GPU stream
    magma_queue_t stream[2];
    magma_event_t event[1];
    magma_queue_create( &stream[0] );
    magma_queue_create( &stream[1] );
    magma_event_create( &event[0] );

    // workspace
    magma_s_vector q, r,rr,p,v,s,t;
    float *d1, *d2, *skp;
    magma_smalloc( &d1, dofs*(2) );
    magma_smalloc( &d2, dofs*(2) );
    // array for the parameters
    magma_smalloc( &skp, 8 );       
    // skp = [alpha|beta|omega|rho_old|rho|nom|tmp1|tmp2]
    magma_s_vinit( &q, Magma_DEV, dofs*6, c_zero );

    // q = rr|r|p|v|s|t
    rr.memory_location = Magma_DEV; rr.val = NULL; rr.num_rows = rr.nnz = dofs;
    r.memory_location = Magma_DEV; r.val = NULL; r.num_rows = r.nnz = dofs;
    p.memory_location = Magma_DEV; p.val = NULL; p.num_rows = p.nnz = dofs;
    v.memory_location = Magma_DEV; v.val = NULL; v.num_rows = v.nnz = dofs;
    s.memory_location = Magma_DEV; s.val = NULL; s.num_rows = s.nnz = dofs;
    t.memory_location = Magma_DEV; t.val = NULL; t.num_rows = t.nnz = dofs;

    rr.val = q(0);
    r.val = q(1);
    p.val = q(2);
    v.val = q(3);
    s.val = q(4);
    t.val = q(5);
    
    // solver variables
    float alpha, beta, omega, rho_old, rho_new, *skp_h;
    float nom, nom0, betanom, r0, den;

    // solver setup
    magma_sscal( dofs, c_zero, x->val, 1) ;                            // x = 0
    magma_scopy( dofs, b.val, 1, q(0), 1 );                            // rr = b
    magma_scopy( dofs, b.val, 1, q(1), 1 );                            // r = b

    rho_new = magma_sdot( dofs, r.val, 1, r.val, 1 );             // rho=<rr,r>
    nom = MAGMA_S_REAL(magma_sdot( dofs, r.val, 1, r.val, 1 ));    
    nom0 = betanom = sqrt(nom);                                 // nom = || r ||                            
    rho_old = omega = alpha = MAGMA_S_MAKE( 1.0, 0. );
    beta = rho_new;
    solver_par->init_res = nom0;
    // array on host for the parameters    
    magma_smalloc_cpu( &skp_h, 8 );
    skp_h[0]=alpha; 
    skp_h[1]=beta; 
    skp_h[2]=omega; 
    skp_h[3]=rho_old; 
    skp_h[4]=rho_new; 
    skp_h[5]=MAGMA_S_MAKE(nom, 0.0);
    magma_ssetvector( 8, skp_h, 1, skp, 1 );
    magma_s_spmv( c_one, A, r, c_zero, v );                     // z = A r
    den = MAGMA_S_REAL( magma_sdot(dofs, v.val, 1, r.val, 1) );// den = z dot r

    if ( (r0 = nom * solver_par->epsilon) < ATOLERANCE ) 
        r0 = ATOLERANCE;
    if ( nom < r0 )
        return MAGMA_SUCCESS;
    // check positive definite  
    if (den <= 0.0) {
        printf("Operator A is not postive definite. (Ar,r) = %f\n", den);
        return -100;
    }

    //Chronometry
    real_Double_t tempo1, tempo2;
    magma_device_sync(); tempo1=magma_wtime();
    if( solver_par->verbose > 0 ){
        solver_par->res_vec[0] = nom0;
        solver_par->timing[0] = 0.0;
    }

    // start iteration
    for( solver_par->numiter= 1; solver_par->numiter<solver_par->maxiter; 
                                                    solver_par->numiter++ ){

        magmablasSetKernelStream(stream[0]);

        // computes p=r+beta*(p-omega*v)
        magma_sbicgmerge1( dofs, skp, v.val, r.val, p.val );

        magma_s_spmv( c_one, A, p, c_zero, v );                 // v = Ap

        magma_smdotc( dofs, 1, q.val, v.val, d1, d2, skp );                     
        magma_sbicgmerge4(  1, skp );
        magma_sbicgmerge2( dofs, skp, r.val, v.val, s.val );    // s=r-alpha*v

        magma_s_spmv( c_one, A, s, c_zero, t );                 // t=As

        magma_smdotc( dofs, 2, q.val+4*dofs, t.val, d1, d2, skp+6 );
        magma_sbicgmerge4(  2, skp );
        magma_sbicgmerge3( dofs, skp, p.val, s.val,     // x=x+alpha*p+omega*s
                            t.val, x->val, r.val );     // r=s-omega*t
        magma_smdotc( dofs, 2, q.val, r.val, d1, d2, skp+4);
        magma_sbicgmerge4(  3, skp );

        // check stopping criterion (asynchronous copy)
        magma_sgetvector_async( 1 , skp+5, 1, 
                                                        skp_h+5, 1, stream[1] );
        betanom = sqrt(MAGMA_S_REAL(skp_h[5]));

        if( solver_par->verbose > 0 ){
            magma_device_sync(); tempo2=magma_wtime();
            if( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        
        if (  betanom  < r0 ) {
            break;
        }
    }
    magma_device_sync(); tempo2=magma_wtime();
    solver_par->runtime = (real_Double_t) tempo2-tempo1;
    float residual;
    magma_sresidual( A, b, *x, &residual );
    solver_par->iter_res = betanom;
    solver_par->final_res = residual;

    if( solver_par->numiter < solver_par->maxiter){
        solver_par->info = 0;
    }else if( solver_par->init_res > solver_par->final_res ){
        if( solver_par->verbose > 0 ){
            if( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        solver_par->info = -2;
    }
    else{
        if( solver_par->verbose > 0 ){
            if( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose] 
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        solver_par->info = -1;
    }
    magma_s_vfree(&q);  // frees all vectors

    magma_free(d1);
    magma_free(d2);
    magma_free( skp );
    magma_free_cpu( skp_h );

    return MAGMA_SUCCESS;
}   /* sbicgstab_merge */
예제 #3
0
/**
    Purpose
    -------
    SLAHR2 reduces the first NB columns of a real general n-BY-(n-k+1)
    matrix A so that elements below the k-th subdiagonal are zero. The
    reduction is performed by an orthogonal similarity transformation
    Q' * A * Q. The routine returns the matrices V and T which determine
    Q as a block reflector I - V*T*V', and also the matrix Y = A * V.
    (Note this is different than LAPACK, which computes Y = A * V * T.)

    This is an auxiliary routine called by SGEHRD.

    Arguments
    ---------
    @param[in]
    n       INTEGER
            The order of the matrix A.

    @param[in]
    k       INTEGER
            The offset for the reduction. Elements below the k-th
            subdiagonal in the first NB columns are reduced to zero.
            K < N.

    @param[in]
    nb      INTEGER
            The number of columns to be reduced.

    @param[in,out]
    A       REAL array, dimension (LDA,N-K+1)
            On entry, the n-by-(n-k+1) general matrix A.
            On exit, the elements on and above the k-th subdiagonal in
            the first NB columns are overwritten with the corresponding
            elements of the reduced matrix; the elements below the k-th
            subdiagonal, with the array TAU, represent the matrix Q as a
            product of elementary reflectors. The other columns of A are
            unchanged. See Further Details.

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

    @param[out]
    tau     REAL array, dimension (NB)
            The scalar factors of the elementary reflectors. See Further
            Details.

    @param[out]
    T       REAL array, dimension (LDT,NB)
            The upper triangular matrix T.

    @param[in]
    ldt     INTEGER
            The leading dimension of the array T.  LDT >= NB.

    @param[out]
    Y       REAL array, dimension (LDY,NB)
            The n-by-nb matrix Y.

    @param[in]
    ldy     INTEGER
            The leading dimension of the array Y. LDY >= N.

    @param[in,out]
    data    Structure with pointers to dA, dT, dV, dW, dY
            which are distributed across multiple GPUs.

    Further Details
    ---------------
    The matrix Q is represented as a product of nb elementary reflectors

       Q = H(1) H(2) . . . H(nb).

    Each H(i) has the form

       H(i) = I - tau * v * v'

    where tau is a real scalar, and v is a real vector with
    v(1:i+k-1) = 0, v(i+k) = 1; v(i+k+1:n) is stored on exit in
    A(i+k+1:n,i), and tau in TAU(i).

    The elements of the vectors v together form the (n-k+1)-by-nb matrix
    V which is needed, with T and Y, to apply the transformation to the
    unreduced part of the matrix, using an update of the form:
    A := (I - V*T*V') * (A - Y*T*V').

    The contents of A on exit are illustrated by the following example
    with n = 7, k = 3 and nb = 2:

    @verbatim
       ( a   a   a   a   a )
       ( a   a   a   a   a )
       ( a   a   a   a   a )
       ( h   h   a   a   a )
       ( v1  h   a   a   a )
       ( v1  v2  a   a   a )
       ( v1  v2  a   a   a )
    @endverbatim

    where "a" denotes an element of the original matrix A, h denotes a
    modified element of the upper Hessenberg matrix H, and vi denotes an
    element of the vector defining H(i).

    This implementation follows the hybrid algorithm and notations described in

    S. Tomov and J. Dongarra, "Accelerating the reduction to upper Hessenberg
    form through hybrid GPU-based computing," University of Tennessee Computer
    Science Technical Report, UT-CS-09-642 (also LAPACK Working Note 219),
    May 24, 2009.

    @ingroup magma_sgeev_aux
    ********************************************************************/
extern "C" magma_int_t
magma_slahr2_m(
    magma_int_t n, magma_int_t k, magma_int_t nb,
    float *A, magma_int_t lda,
    float *tau,
    float *T, magma_int_t ldt,
    float *Y, magma_int_t ldy,
    struct sgehrd_data *data )
{
    #define  A(  i, j ) ( A + (i) + (j)*lda)
    #define  Y(  i, j ) ( Y + (i) + (j)*ldy)
    #define  T(  i, j ) ( T + (i) + (j)*ldt)
    #define dA(  d, i, j ) (data->A [d] + (i) + (j)*ldda)
    #define dTi( d       ) (data->Ti[d])
    #define dV(  d, i, j ) (data->V [d] + (i) + (j)*ldv )
    #define dVd( d, i, j ) (data->Vd[d] + (i) + (j)*ldvd)
    #define dY(  d, i, j ) (data->Y [d] + (i) + (j)*ldda)

    float c_zero    = MAGMA_S_ZERO;
    float c_one     = MAGMA_S_ONE;
    float c_neg_one = MAGMA_S_NEG_ONE;
    float tmp;

    magma_int_t ngpu = data->ngpu;
    magma_int_t ldda = data->ldda;
    magma_int_t ldv  = data->ldv;
    magma_int_t ldvd = data->ldvd;
    
    magma_int_t ione = 1;
    
    magma_int_t d, dki1, dn, nblocks, gblock, lblock, lgid;
    magma_int_t n_k_i_1, n_k;
    float scale;

    magma_int_t i;
    float ei = MAGMA_S_ZERO;

    magma_int_t info_data = 0;
    magma_int_t *info = &info_data;
    if (n < 0) {
        *info = -1;
    } else if (k < 0 || k >= n) {
        *info = -2;
    } else if (nb < 1 || nb > n) {
        *info = -3;
    } else if (lda < max(1,n)) {
        *info = -5;
    } else if (ldt < nb) {
        *info = -8;
    } else if (ldy < max(1,n)) {
        *info = -10;
    }
    if (*info != 0) {
        magma_xerbla( __func__, -(*info) );
        return *info;
    }
    
    // adjust from 1-based indexing
    k -= 1;

    // Function Body
    if (n <= 1)
        return *info;
    
    magma_device_t orig_dev;
    magma_getdevice( &orig_dev );
    
    // zero out current top block of V on all GPUs
    for( d = 0; d < ngpu; ++d ) {
        magma_setdevice( d );
        magmablas_slaset( MagmaFull, nb, nb, c_zero, c_zero, dV(d,k,0), ldv, data->queues[d] );
    }
    
    // set all Y=0
    lapackf77_slaset( "Full", &n, &nb, &c_zero, &c_zero, Y, &ldy );
    
    for (i = 0; i < nb; ++i) {
        n_k_i_1 = n - k - i - 1;
        n_k     = n - k;
        
        if (i > 0) {
            // Finish applying I - V * T * V' on right
            tmp = MAGMA_S_NEGATE( tau[i-1] );
            blasf77_saxpy( &n_k, &tmp, Y(k,i-1), &ione, A(k,i), &ione );
            
            // Apply I - V * T' * V' to this column (call it b) from the
            // left, using the last column of T as workspace, w.
            //
            // Let  V = ( V1 )   and   b = ( b1 )   (first i-1 rows)
            //          ( V2 )             ( b2 )
            // where V1 is unit lower triangular
            
            // w := b1 = A(k+1:k+i, i)
            blasf77_scopy( &i,
                           A(k+1,i), &ione,
                           T(0,nb-1), &ione );
            
            // w := V1' * b1 = VA(k+1:k+i, 0:i-1)' * w
            blasf77_strmv( "Lower", "Conj", "Unit", &i,
                           A(k+1,0), &lda,
                           T(0,nb-1), &ione );
            
            // w := w + V2'*b2 = w + VA(k+i+1:n-1, 0:i-1)' * A(k+i+1:n-1, i)
            blasf77_sgemv( "Conj", &n_k_i_1, &i,
                           &c_one, A(k+i+1,0), &lda,
                                   A(k+i+1,i), &ione,
                           &c_one, T(0,nb-1), &ione );
            
            // w := T'*w = T(0:i-1, 0:i-1)' * w
            blasf77_strmv( "Upper", "Conj", "Non-unit", &i,
                           T(0,0), &ldt,
                           T(0,nb-1), &ione );
            
            // b2 := b2 - V2*w = A(k+i+1:n-1, i) - VA(k+i+1:n-1, 0:i-1) * w
            blasf77_sgemv( "No trans", &n_k_i_1, &i,
                           &c_neg_one, A(k+i+1,0), &lda,
                                       T(0,nb-1), &ione,
                           &c_one,     A(k+i+1,i), &ione );
            
            // w := V1*w = VA(k+1:k+i, 0:i-1) * w
            blasf77_strmv( "Lower", "No trans", "Unit", &i,
                           A(k+1,0), &lda,
                           T(0,nb-1), &ione );
            
            // b1 := b1 - w = A(k+1:k+i-1, i) - w
            blasf77_saxpy( &i,
                           &c_neg_one, T(0,nb-1), &ione,
                                       A(k+1,i), &ione );
            
            // Restore diagonal element, saved below during previous iteration
            *A(k+i,i-1) = ei;
        }
        
        // Generate the elementary reflector H(i) to annihilate A(k+i+1:n-1,i)
        lapackf77_slarfg( &n_k_i_1,
                          A(k+i+1,i),
                          A(k+i+2,i), &ione, &tau[i] );
        // Save diagonal element and set to one, to simplify multiplying by V
        ei = *A(k+i+1,i);
        *A(k+i+1,i) = c_one;

        // compute yi = A vi = sum_g A{d} vi{d}
        nblocks = (n-1) / nb / ngpu + 1;
        for( d = 0; d < ngpu; ++d ) {
            magma_setdevice( d );
            
            // dV(k+i+1:n-1, i) = VA(k+i:n, i)
            magma_ssetvector_async( n_k_i_1,
                                    A(k+i+1,i), 1,
                                    dV(d, k+i+1, i), 1, data->queues[d] );
            
            // copy column of dV -> dVd, using block cyclic distribution.
            // This assumes V and Vd have been padded so that
            // a 2D matrix copy doesn't access them out-of-bounds
            gblock = k / nb;
            lblock = gblock / ngpu;
            lgid   = gblock % ngpu;
            if ( d < lgid ) {
                lblock += 1;
            }
            // treat V as (nb*ngpu) x nblock matrix, and Vd as nb x nblock matrix
            magmablas_slacpy( MagmaFull, nb, nblocks-lblock,
                              dV (d, d*nb + lblock*nb*ngpu, i), nb*ngpu,
                              dVd(d, 0    + lblock*nb,      i), nb, data->queues[d] );
            
            // convert global indices (k) to local indices (dk)
            magma_indices_1D_bcyclic( nb, ngpu, d, k+i+1, n, &dki1, &dn );
            
            // dY(k:n, i) = dA(k:n, k+i+1:n) * dV(k+i+1:n, i)
            // skip if matrix is empty
            // each GPU copies to different temporary vector in Y,
            // which are summed in separate loop below
            if ( dn-dki1 > 0 ) {
                magma_sgemv( MagmaNoTrans, n-k, dn-dki1,
                             c_one,  dA (d, k,    dki1), ldda,
                                     dVd(d, dki1,    i), 1,
                             c_zero, dY (d, k,       i), 1, data->queues[d] );
                
                // copy vector to host, storing in column nb+d of Y
                // as temporary space (Y has >= nb+ngpu columns)
                magma_sgetvector_async( n-k,
                                        dY(d, k, i), 1,
                                        Y(k, nb+d),  1, data->queues[d] );
            }
        }
        
        // while GPU is doing above Ag*v...
        // Compute T(0:i,i) = [ -tau T V' vi ]
        //                    [  tau         ]
        // T(0:i-1, i) = -tau VA(k+i+1:n-1, 0:i-1)' VA(k+i+1:n-1, i)
        scale = MAGMA_S_NEGATE( tau[i] );
        blasf77_sgemv( "Conj", &n_k_i_1, &i,
                       &scale,  A(k+i+1,0), &lda,
                                A(k+i+1,i), &ione,
                       &c_zero, T(0,i), &ione );
        // T(0:i-1, i) = T(0:i-1, 0:i-1) * T(0:i-1, i)
        blasf77_strmv( "Upper", "No trans", "Non-unit", &i,
                       T(0,0), &ldt,
                       T(0,i), &ione );
        *T(i,i) = tau[i];
        
        // apply reflectors to next column, A(i+1), on right only.
        // one axpy will be required to finish this, in the next iteration above
        if ( i > 0 && i+1 < nb ) {
            // Update next column, A(k:n,i+1), applying Q on right.
            // One axpy will be required to finish this, in the next iteration
            // above, after yi is computed.
            // This updates one more row than LAPACK does (row k),
            // making block above panel an even multiple of nb.
            // Use last column of T as workspace, w.
            magma_int_t i1 = i+1;
            
            // If real, conjugate row of V, and undo afterwards
            #ifdef COMPLEX
            lapackf77_slacgv( &i1,  A(k+i1,0), &lda );
            #endif
            // w = T(0:i, 0:i+1) * VA(k+i+1, 0:i+1)'
            // T is now rectangular, so we use gemv instead of trmv as in lapack.
            blasf77_sgemv( "No trans", &i, &i1,
                           &c_one,  T(0,0), &ldt,
                                    A(k+i1,0), &lda,
                           &c_zero, T(0,nb-1), &ione );
            #ifdef COMPLEX
            lapackf77_slacgv( &i1,  A(k+i1,0), &lda );
            #endif
            
            // A(k:n, i+1) -= Y(k:n, 0:i) * w
            blasf77_sgemv( "No trans", &n_k, &i,
                           &c_neg_one, Y(k,0), &ldy,
                                       T(0,nb-1), &ione,
                           &c_one,     A(k,i1), &ione );
        }
        
        // yi = sum_g yi{d}
        for( d = 0; d < ngpu; ++d ) {
            magma_setdevice( d );
            magma_queue_sync( data->queues[d] );
            magma_indices_1D_bcyclic( nb, ngpu, d, k+i+1, n, &dki1, &dn );
            if ( dn-dki1 > 0 ) {
                // yi = yi + yi{d}
                blasf77_saxpy( &n_k, &c_one, Y(k,nb+d), &ione, Y(k,i), &ione );
            }
        }
    }
    // Restore diagonal element
    *A(k+nb,nb-1) = ei;
    
    // compute Y = Am V = sum_g Am{d} V{d} --- top part, Y(0:k-1,:)
    for( d = 0; d < ngpu; ++d ) {
        magma_setdevice( d );
        
        // convert global indices (k) to local indices (dk)
        magma_indices_1D_bcyclic( nb, ngpu, d, k+1, n, &dki1, &dn );
        
        // dY(0:k, :) = dA(0:k, k+i+1:n-1) * dV(k+i+1:n-1, :)
        // skip if matrix is empty
        // each GPU copies to different temporary block in Y,
        // which are summed in separate loop below
        if ( dn-dki1 > 0 ) {
            magma_sgemm( MagmaNoTrans, MagmaNoTrans, k, nb, dn-dki1,
                         c_one,  dA (d, 0,    dki1), ldda,
                                 dVd(d, dki1,    0), ldvd,
                         c_zero, dY (d, 0,       0), ldda, data->queues[d] );
            
            // copy result to host, storing in columns [nb + nb*d : nb + nb*(d+1)] of Y
            // as temporary space (Y has nb + nb*ngpu columns)
            magma_sgetmatrix_async( k, nb,
                                    dY(d, 0, 0),  ldda,
                                    Y(0,nb+nb*d), ldy, data->queues[d] );
        }
    }
    
    // Y = sum_g Y{d}
    for( d = 0; d < ngpu; ++d ) {
        magma_setdevice( d );
        magma_queue_sync( 0 );
        magma_indices_1D_bcyclic( nb, ngpu, d, k+1, n, &dki1, &dn );
        if ( dn-dki1 > 0 ) {
            // Y = Y + Am V
            for( i = 0; i < nb; ++i ) {
                blasf77_saxpy( &k, &c_one, Y(0,nb+nb*d+i), &ione, Y(0,i), &ione );
            }
        }
    }
    
    // copy Y and T matrices to GPUs
    for( d = 0; d < ngpu; ++d ) {
        magma_setdevice( d );
        magma_ssetmatrix_async( n, nb, Y, ldy, dY(d, 0, 0), ldda, data->queues[d] );
        magma_ssetmatrix_async( nb, nb, T, nb, dTi(d),      nb,   data->queues[d] );
    }

    magma_setdevice( orig_dev );
    
    return *info;
} /* magma_slahr2 */
예제 #4
0
extern "C" magma_int_t
magma_sbicgstab_merge3(
    magma_s_matrix A, magma_s_matrix b,
    magma_s_matrix *x, magma_s_solver_par *solver_par,
    magma_queue_t queue )
{
    magma_int_t info = MAGMA_NOTCONVERGED;
    
    // prepare solver feedback
    solver_par->solver = Magma_BICGSTABMERGE;
    solver_par->numiter = 0;
    solver_par->spmv_count = 0;
    
    // solver variables
    float alpha, beta, omega, rho_old, rho_new, *skp_h={0};
    float nom, nom0, betanom, nomb;

    // some useful variables
    float c_zero = MAGMA_S_ZERO, c_one = MAGMA_S_ONE;
    
    magma_int_t dofs = A.num_rows;

    // workspace
    magma_s_matrix q={Magma_CSR}, r={Magma_CSR}, rr={Magma_CSR}, p={Magma_CSR}, v={Magma_CSR}, s={Magma_CSR}, t={Magma_CSR};
    float *d1=NULL, *d2=NULL, *skp=NULL;
    d1 = NULL;
    d2 = NULL;
    skp = NULL;
    CHECK( magma_smalloc( &d1, dofs*(2) ));
    CHECK( magma_smalloc( &d2, dofs*(2) ));
    // array for the parameters
    CHECK( magma_smalloc( &skp, 8 ));
    // skp = [alpha|beta|omega|rho_old|rho|nom|tmp1|tmp2]
    CHECK( magma_svinit( &q, Magma_DEV, dofs*6, 1, c_zero, queue ));

    // q = rr|r|p|v|s|t
    rr.memory_location = Magma_DEV; rr.dval = NULL; rr.num_rows = rr.nnz = dofs; rr.num_cols = 1; rr.storage_type = Magma_DENSE;
    r.memory_location = Magma_DEV; r.dval = NULL; r.num_rows = r.nnz = dofs; r.num_cols = 1; r.storage_type = Magma_DENSE;
    p.memory_location = Magma_DEV; p.dval = NULL; p.num_rows = p.nnz = dofs; p.num_cols = 1; p.storage_type = Magma_DENSE;
    v.memory_location = Magma_DEV; v.dval = NULL; v.num_rows = v.nnz = dofs; v.num_cols = 1; v.storage_type = Magma_DENSE;
    s.memory_location = Magma_DEV; s.dval = NULL; s.num_rows = s.nnz = dofs; s.num_cols = 1; s.storage_type = Magma_DENSE;
    t.memory_location = Magma_DEV; t.dval = NULL; t.num_rows = t.nnz = dofs; t.num_cols = 1; t.storage_type = Magma_DENSE;

    rr.dval = q(0);
    r.dval = q(1);
    p.dval = q(2);
    v.dval = q(3);
    s.dval = q(4);
    t.dval = q(5);

    // solver setup
    CHECK(  magma_sresidualvec( A, b, *x, &r, &nom0, queue));
    magma_scopy( dofs, r.dval, 1, q(0), 1, queue );                            // rr = r
    magma_scopy( dofs, r.dval, 1, q(1), 1, queue );                            // q = r
    betanom = nom0;
    nom = nom0*nom0;
    rho_new = magma_sdot( dofs, r.dval, 1, r.dval, 1, queue );             // rho=<rr,r>
    rho_old = omega = alpha = MAGMA_S_MAKE( 1.0, 0. );
    beta = rho_new;
    solver_par->init_res = nom0;
    // array on host for the parameters
    CHECK( magma_smalloc_cpu( &skp_h, 8 ));
    
    nomb = magma_snrm2( dofs, b.dval, 1, queue );
    if ( nomb == 0.0 ){
        nomb=1.0;
    }       
    solver_par->final_res = solver_par->init_res;
    solver_par->iter_res = solver_par->init_res;
    if ( solver_par->verbose > 0 ) {
        solver_par->res_vec[0] = nom0;
        solver_par->timing[0] = 0.0;
    }
    
    skp_h[0]=alpha;
    skp_h[1]=beta;
    skp_h[2]=omega;
    skp_h[3]=rho_old;
    skp_h[4]=rho_new;
    skp_h[5]=MAGMA_S_MAKE(nom, 0.0);
    magma_ssetvector( 8, skp_h, 1, skp, 1, queue );
    CHECK( magma_s_spmv( c_one, A, r, c_zero, v, queue ));             // z = A r
    nomb = magma_snrm2( dofs, b.dval, 1, queue );
    if( nom0 < solver_par->atol ||
        nom0/nomb < solver_par->rtol ){
        info = MAGMA_SUCCESS;
        goto cleanup;
    }

    //Chronometry
    real_Double_t tempo1, tempo2;
    tempo1 = magma_sync_wtime( queue );

    solver_par->numiter = 0;
    solver_par->spmv_count = 0;
    // start iteration
    do
    {
        solver_par->numiter++;

        // computes p=r+beta*(p-omega*v)
        CHECK( magma_sbicgmerge1( dofs, skp, v.dval, r.dval, p.dval, queue ));

        CHECK( magma_s_spmv( c_one, A, p, c_zero, v, queue ));         // v = Ap
        solver_par->spmv_count++;
        CHECK( magma_smdotc( dofs, 1, q.dval, v.dval, d1, d2, skp, queue ));
        CHECK( magma_sbicgmerge4(  1, skp, queue ));
        CHECK( magma_sbicgmerge2( dofs, skp, r.dval, v.dval, s.dval, queue )); // s=r-alpha*v

        CHECK( magma_s_spmv( c_one, A, s, c_zero, t, queue ));         // t=As
        solver_par->spmv_count++;
        CHECK( magma_smdotc( dofs, 2, q.dval+4*dofs, t.dval, d1, d2, skp+6, queue ));
        CHECK( magma_sbicgmerge4(  2, skp, queue ));

        CHECK( magma_sbicgmerge_xrbeta( dofs, d1, d2, q.dval, r.dval, p.dval,
                                                    s.dval, t.dval, x->dval, skp, queue ));

        // check stopping criterion
        magma_sgetvector_async( 1 , skp+5, 1, skp_h+5, 1, queue );
        betanom = sqrt(MAGMA_S_REAL(skp_h[5]));

        if ( solver_par->verbose > 0 ) {
            tempo2 = magma_sync_wtime( queue );
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        
        if (  betanom  < solver_par->atol || 
              betanom/nomb < solver_par->rtol ) {
            break;
        }
    }
    while ( solver_par->numiter+1 <= solver_par->maxiter );
    
    tempo2 = magma_sync_wtime( queue );
    solver_par->runtime = (real_Double_t) tempo2-tempo1;
    float residual;
    CHECK(  magma_sresidualvec( A, b, *x, &r, &residual, queue));
    solver_par->iter_res = betanom;
    solver_par->final_res = residual;

    if ( solver_par->numiter < solver_par->maxiter ) {
        info = MAGMA_SUCCESS;
    } else if ( solver_par->init_res > solver_par->final_res ) {
        if ( solver_par->verbose > 0 ) {
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        info = MAGMA_SLOW_CONVERGENCE;
        if( solver_par->iter_res < solver_par->atol ||
            solver_par->iter_res/solver_par->init_res < solver_par->rtol ){
            info = MAGMA_SUCCESS;
        }
    }
    else {
        if ( solver_par->verbose > 0 ) {
            if ( (solver_par->numiter)%solver_par->verbose==0 ) {
                solver_par->res_vec[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) betanom;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        info = MAGMA_DIVERGENCE;
    }
    
cleanup:
    magma_smfree(&q, queue );  // frees all vectors
    magma_free(d1);
    magma_free(d2);
    magma_free( skp );
    magma_free_cpu( skp_h );

    solver_par->info = info;
    return info;
}   /* sbicgstab_merge */
예제 #5
0
extern "C" magma_int_t
magma_sidr_strms(
    magma_s_matrix A, magma_s_matrix b, magma_s_matrix *x,
    magma_s_solver_par *solver_par,
    magma_queue_t queue )
{
    magma_int_t info = MAGMA_NOTCONVERGED;

    // prepare solver feedback
    solver_par->solver = Magma_IDRMERGE;
    solver_par->numiter = 0;
    solver_par->spmv_count = 0;
    solver_par->init_res = 0.0;
    solver_par->final_res = 0.0;
    solver_par->iter_res = 0.0;
    solver_par->runtime = 0.0;

    // constants
    const float c_zero = MAGMA_S_ZERO;
    const float c_one = MAGMA_S_ONE;
    const float c_n_one = MAGMA_S_NEG_ONE;

    // internal user options
    const magma_int_t smoothing = 1;   // 0 = disable, 1 = enable
    const float angle = 0.7;          // [0-1]

    // local variables
    magma_int_t iseed[4] = {0, 0, 0, 1};
    magma_int_t dof;
    magma_int_t s;
    magma_int_t distr;
    magma_int_t k, i, sk;
    magma_int_t innerflag;
    magma_int_t ldd;
    magma_int_t q;
    float residual;
    float nrm;
    float nrmb;
    float nrmr;
    float nrmt;
    float rho;
    float om;
    float gamma;

    // matrices and vectors
    magma_s_matrix dxs = {Magma_CSR};
    magma_s_matrix dr = {Magma_CSR}, drs = {Magma_CSR};
    magma_s_matrix dP = {Magma_CSR}, dP1 = {Magma_CSR};
    magma_s_matrix dG = {Magma_CSR}, dGcol = {Magma_CSR};
    magma_s_matrix dU = {Magma_CSR};
    magma_s_matrix dM = {Magma_CSR};
    magma_s_matrix df = {Magma_CSR};
    magma_s_matrix dt = {Magma_CSR}, dtt = {Magma_CSR};
    magma_s_matrix dc = {Magma_CSR};
    magma_s_matrix dv = {Magma_CSR};
    magma_s_matrix dskp = {Magma_CSR};
    magma_s_matrix dalpha = {Magma_CSR};
    magma_s_matrix dbeta = {Magma_CSR};
    float *hMdiag = NULL;
    float *hskp = NULL;
    float *halpha = NULL;
    float *hbeta = NULL;
    float *d1 = NULL, *d2 = NULL;
    
    // queue variables
    const magma_int_t nqueues = 3;     // number of queues
    magma_queue_t queues[nqueues];    

    // chronometry
    real_Double_t tempo1, tempo2;

    // create additional queues
    queues[0] = queue;
    for ( q = 1; q < nqueues; q++ ) {
        magma_queue_create( queue->device(), &(queues[q]) );
    }

    // initial s space
    // TODO: add option for 's' (shadow space number)
    // Hack: uses '--restart' option as the shadow space number.
    //       This is not a good idea because the default value of restart option is used to detect
    //       if the user provided a custom restart. This means that if the default restart value
    //       is changed then the code will think it was the user (unless the default value is
    //       also updated in the 'if' statement below.
    s = 1;
    if ( solver_par->restart != 50 ) {
        if ( solver_par->restart > A.num_cols ) {
            s = A.num_cols;
        } else {
            s = solver_par->restart;
        }
    }
    solver_par->restart = s;

    // set max iterations
    solver_par->maxiter = min( 2 * A.num_cols, solver_par->maxiter );

    // check if matrix A is square
    if ( A.num_rows != A.num_cols ) {
        //printf("Matrix A is not square.\n");
        info = MAGMA_ERR_NOT_SUPPORTED;
        goto cleanup;
    }

    // |b|
    nrmb = magma_snrm2( b.num_rows, b.dval, 1, queue );
    if ( nrmb == 0.0 ) {
        magma_sscal( x->num_rows, MAGMA_S_ZERO, x->dval, 1, queue );
        info = MAGMA_SUCCESS;
        goto cleanup;
    }

    // t = 0
    // make t twice as large to contain both, dt and dr
    ldd = magma_roundup( b.num_rows, 32 );
    CHECK( magma_svinit( &dt, Magma_DEV, ldd, 2, c_zero, queue ));
    dt.num_rows = b.num_rows;
    dt.num_cols = 1;
    dt.nnz = dt.num_rows;

    // redirect the dr.dval to the second part of dt
    CHECK( magma_svinit( &dr, Magma_DEV, b.num_rows, 1, c_zero, queue ));
    magma_free( dr.dval );
    dr.dval = dt.dval + ldd;

    // r = b - A x
    CHECK( magma_sresidualvec( A, b, *x, &dr, &nrmr, queue ));
    
    // |r|
    solver_par->init_res = nrmr;
    solver_par->final_res = solver_par->init_res;
    solver_par->iter_res = solver_par->init_res;
    if ( solver_par->verbose > 0 ) {
        solver_par->res_vec[0] = (real_Double_t)nrmr;
    }

    // check if initial is guess good enough
    if ( nrmr <= solver_par->atol ||
        nrmr/nrmb <= solver_par->rtol ) {
        info = MAGMA_SUCCESS;
        goto cleanup;
    }

    // P = randn(n, s)
    // P = ortho(P)
//---------------------------------------
    // P = 0.0
    CHECK( magma_svinit( &dP, Magma_CPU, A.num_cols, s, c_zero, queue ));

    // P = randn(n, s)
    distr = 3;        // 1 = unif (0,1), 2 = unif (-1,1), 3 = normal (0,1) 
    dof = dP.num_rows * dP.num_cols;
    lapackf77_slarnv( &distr, iseed, &dof, dP.val );

    // transfer P to device
    CHECK( magma_smtransfer( dP, &dP1, Magma_CPU, Magma_DEV, queue ));
    magma_smfree( &dP, queue );

    // P = ortho(P1)
    if ( dP1.num_cols > 1 ) {
        // P = magma_sqr(P1), QR factorization
        CHECK( magma_sqr( dP1.num_rows, dP1.num_cols, dP1, dP1.ld, &dP, NULL, queue ));
    } else {
        // P = P1 / |P1|
        nrm = magma_snrm2( dof, dP1.dval, 1, queue );
        nrm = 1.0 / nrm;
        magma_sscal( dof, nrm, dP1.dval, 1, queue );
        CHECK( magma_smtransfer( dP1, &dP, Magma_DEV, Magma_DEV, queue ));
    }
    magma_smfree( &dP1, queue );
//---------------------------------------

    // allocate memory for the scalar products
    CHECK( magma_smalloc_pinned( &hskp, 5 ));
    CHECK( magma_svinit( &dskp, Magma_DEV, 4, 1, c_zero, queue ));

    CHECK( magma_smalloc_pinned( &halpha, s ));
    CHECK( magma_svinit( &dalpha, Magma_DEV, s, 1, c_zero, queue ));

    CHECK( magma_smalloc_pinned( &hbeta, s ));
    CHECK( magma_svinit( &dbeta, Magma_DEV, s, 1, c_zero, queue ));
    
    // workspace for merged dot product
    CHECK( magma_smalloc( &d1, max(2, s) * b.num_rows ));
    CHECK( magma_smalloc( &d2, max(2, s) * b.num_rows ));

    // smoothing enabled
    if ( smoothing > 0 ) {
        // set smoothing solution vector
        CHECK( magma_smtransfer( *x, &dxs, Magma_DEV, Magma_DEV, queue ));

        // tt = 0
        // make tt twice as large to contain both, dtt and drs
        ldd = magma_roundup( b.num_rows, 32 );
        CHECK( magma_svinit( &dtt, Magma_DEV, ldd, 2, c_zero, queue ));
        dtt.num_rows = dr.num_rows;
        dtt.num_cols = 1;
        dtt.nnz = dtt.num_rows;

        // redirect the drs.dval to the second part of dtt
        CHECK( magma_svinit( &drs, Magma_DEV, dr.num_rows, 1, c_zero, queue ));
        magma_free( drs.dval );
        drs.dval = dtt.dval + ldd;

        // set smoothing residual vector
        magma_scopyvector( dr.num_rows, dr.dval, 1, drs.dval, 1, queue );
    }

    // G(n,s) = 0
    if ( s > 1 ) {
        ldd = magma_roundup( A.num_rows, 32 );
        CHECK( magma_svinit( &dG, Magma_DEV, ldd, s, c_zero, queue ));
        dG.num_rows = A.num_rows;
    } else {
        CHECK( magma_svinit( &dG, Magma_DEV, A.num_rows, s, c_zero, queue ));
    }

    // dGcol represents a single column of dG, array pointer is set inside loop
    CHECK( magma_svinit( &dGcol, Magma_DEV, dG.num_rows, 1, c_zero, queue ));
    magma_free( dGcol.dval );

    // U(n,s) = 0
    if ( s > 1 ) {
        ldd = magma_roundup( A.num_cols, 32 );
        CHECK( magma_svinit( &dU, Magma_DEV, ldd, s, c_zero, queue ));
        dU.num_rows = A.num_cols;
    } else {
        CHECK( magma_svinit( &dU, Magma_DEV, A.num_cols, s, c_zero, queue ));
    }

    // M(s,s) = I
    CHECK( magma_svinit( &dM, Magma_DEV, s, s, c_zero, queue ));
    CHECK( magma_smalloc_pinned( &hMdiag, s ));
    magmablas_slaset( MagmaFull, dM.num_rows, dM.num_cols, c_zero, c_one, dM.dval, dM.ld, queue );

    // f = 0
    CHECK( magma_svinit( &df, Magma_DEV, dP.num_cols, 1, c_zero, queue ));

    // c = 0
    CHECK( magma_svinit( &dc, Magma_DEV, dM.num_cols, 1, c_zero, queue ));

    // v = r
    CHECK( magma_smtransfer( dr, &dv, Magma_DEV, Magma_DEV, queue ));

    //--------------START TIME---------------
    // chronometry
    tempo1 = magma_sync_wtime( queue );
    if ( solver_par->verbose > 0 ) {
        solver_par->timing[0] = 0.0;
    }

cudaProfilerStart();

    om = MAGMA_S_ONE;
    gamma = MAGMA_S_ZERO;
    innerflag = 0;

    // new RHS for small systems
    // f = P' r
    // Q1
    magma_sgemvmdot_shfl( dP.num_rows, dP.num_cols, dP.dval, dr.dval, d1, d2, df.dval, queues[1] );

    // skp[4] = f(k)
    // Q1
    magma_sgetvector_async( 1, df.dval, 1, &hskp[4], 1, queues[1] );

    // c(k:s) = f(k:s)
    // Q1
    magma_scopyvector_async( s, df.dval, 1, dc.dval, 1, queues[1] );

    // c(k:s) = M(k:s,k:s) \ f(k:s)
    // Q1
    magma_strsv( MagmaLower, MagmaNoTrans, MagmaNonUnit, s, dM.dval, dM.ld, dc.dval, 1, queues[1] );

    // start iteration
    do
    {
        solver_par->numiter++;

        // shadow space loop
        for ( k = 0; k < s; ++k ) {
            sk = s - k;
            dGcol.dval = dG.dval + k * dG.ld;

            // v = r - G(:,k:s) c(k:s)
            // Q1
            magmablas_sgemv( MagmaNoTrans, dG.num_rows, sk, c_n_one, dGcol.dval, dG.ld, &dc.dval[k], 1, c_one, dv.dval, 1, queues[1] );

            // U(:,k) = om * v + U(:,k:s) c(k:s)
            // Q1
            magmablas_sgemv( MagmaNoTrans, dU.num_rows, sk, c_one, &dU.dval[k*dU.ld], dU.ld, &dc.dval[k], 1, om, dv.dval, 1, queues[1] );

            // G(:,k) = A U(:,k)
            // Q1
            CHECK( magma_s_spmv( c_one, A, dv, c_zero, dGcol, queues[1] ));
            solver_par->spmv_count++;

            // bi-orthogonalize the new basis vectors
            for ( i = 0; i < k; ++i ) {
                // alpha = P(:,i)' G(:,k)
                // Q1
                halpha[i] = magma_sdot( dP.num_rows, &dP.dval[i*dP.ld], 1, dGcol.dval, 1, queues[1] );
                // implicit sync Q1 --> alpha = P(:,i)' G(:,k) 

                // alpha = alpha / M(i,i)
                halpha[i] = halpha[i] / hMdiag[i];
                    
                // G(:,k) = G(:,k) - alpha * G(:,i)
                // Q1
                magma_saxpy( dG.num_rows, -halpha[i], &dG.dval[i*dG.ld], 1, dGcol.dval, 1, queues[1] );
            }

            // sync Q1 --> G(:,k) = G(:,k) - alpha * G(:,i), skp[4] = f(k)
            magma_queue_sync( queues[1] );

            // new column of M = P'G, first k-1 entries are zero
            // M(k:s,k) = P(:,k:s)' G(:,k)
            // Q2
            magma_sgemvmdot_shfl( dP.num_rows, sk, &dP.dval[k*dP.ld], dGcol.dval, d1, d2, &dM.dval[k*dM.ld+k], queues[2] );

            // non-first s iteration
            if ( k > 0 ) {
                // alpha = dalpha
                // Q0
                magma_ssetvector_async( k, halpha, 1, dalpha.dval, 1, queues[0] );

                // U update outside of loop using GEMV
                // U(:,k) = U(:,k) - U(:,1:k) * alpha(1:k)
                // Q0
                magmablas_sgemv( MagmaNoTrans, dU.num_rows, k, c_n_one, dU.dval, dU.ld, dalpha.dval, 1, c_one, dv.dval, 1, queues[0] );
            }

            // Mdiag(k) = M(k,k)
            // Q2
            magma_sgetvector( 1, &dM.dval[k*dM.ld+k], 1, &hMdiag[k], 1, queues[2] );
            // implicit sync Q2 --> Mdiag(k) = M(k,k)

            // U(:,k) = v
            // Q0
            magma_scopyvector_async( dU.num_rows, dv.dval, 1, &dU.dval[k*dU.ld], 1, queues[0] );

            // check M(k,k) == 0
            if ( MAGMA_S_EQUAL(hMdiag[k], MAGMA_S_ZERO) ) {
                innerflag = 1;
                info = MAGMA_DIVERGENCE;
                break;
            }

            // beta = f(k) / M(k,k)
            hbeta[k] = hskp[4] / hMdiag[k];

            // check for nan
            if ( magma_s_isnan( hbeta[k] ) || magma_s_isinf( hbeta[k] )) {
                innerflag = 1;
                info = MAGMA_DIVERGENCE;
                break;
            }

            // r = r - beta * G(:,k)
            // Q2
            magma_saxpy( dr.num_rows, -hbeta[k], dGcol.dval, 1, dr.dval, 1, queues[2] );

            // non-last s iteration 
            if ( (k + 1) < s ) {
                // f(k+1:s) = f(k+1:s) - beta * M(k+1:s,k)
                // Q1
                magma_saxpy( sk-1, -hbeta[k], &dM.dval[k*dM.ld+(k+1)], 1, &df.dval[k+1], 1, queues[1] );

                // c(k+1:s) = f(k+1:s)
                // Q1
                magma_scopyvector_async( sk-1, &df.dval[k+1], 1, &dc.dval[k+1], 1, queues[1] );

                // c(k+1:s) = M(k+1:s,k+1:s) \ f(k+1:s)
                // Q1
                magma_strsv( MagmaLower, MagmaNoTrans, MagmaNonUnit, sk-1, &dM.dval[(k+1)*dM.ld+(k+1)], dM.ld, &dc.dval[k+1], 1, queues[1] );

                // skp[4] = f(k+1)
                // Q1
                magma_sgetvector_async( 1, &df.dval[k+1], 1, &hskp[4], 1, queues[1] ); 
            }

            // smoothing disabled
            if ( smoothing <= 0 ) {
                // |r|
                // Q2
                nrmr = magma_snrm2( dr.num_rows, dr.dval, 1, queues[2] );           
                // implicit sync Q2 --> |r|

            // smoothing enabled
            } else {
                // smoothing operation
//---------------------------------------
                // t = rs - r
                // Q2
                magma_sidr_smoothing_1( drs.num_rows, drs.num_cols, drs.dval, dr.dval, dtt.dval, queues[2] );

                // x = x + beta * U(:,k)
                // Q0
                magma_saxpy( x->num_rows, hbeta[k], &dU.dval[k*dU.ld], 1, x->dval, 1, queues[0] );

                // t't
                // t'rs
                // Q2
                CHECK( magma_sgemvmdot_shfl( dt.ld, 2, dtt.dval, dtt.dval, d1, d2, &dskp.dval[2], queues[2] ));

                // skp[2-3] = dskp[2-3]
                // Q2
                magma_sgetvector( 2, &dskp.dval[2], 1, &hskp[2], 1, queues[2] );
                // implicit sync Q2 --> skp = dskp

                // gamma = (t' * rs) / (t' * t)
                gamma = hskp[3] / hskp[2];
                
                // rs = rs - gamma * t 
                // Q1
                magma_saxpy( drs.num_rows, -gamma, dtt.dval, 1, drs.dval, 1, queues[1] );

                // xs = xs - gamma * (xs - x) 
                // Q0
                magma_sidr_smoothing_2( dxs.num_rows, dxs.num_cols, -gamma, x->dval, dxs.dval, queues[0] );

                // |rs|
                // Q1
                nrmr = magma_snrm2( drs.num_rows, drs.dval, 1, queues[1] );       
                // implicit sync Q0 --> |r|
//---------------------------------------
            }

            // v = r
            // Q1
            magma_scopyvector_async( dr.num_rows, dr.dval, 1, dv.dval, 1, queues[1] );

            // last s iteration
            if ( (k + 1) == s ) {
               // t = A r
               // Q2
               CHECK( magma_s_spmv( c_one, A, dr, c_zero, dt, queues[2] ));
               solver_par->spmv_count++;

               // t't
               // t'r
               // Q2
               CHECK( magma_sgemvmdot_shfl( dt.ld, 2, dt.dval, dt.dval, d1, d2, dskp.dval, queues[2] ));
            }

            // store current timing and residual
            if ( solver_par->verbose > 0 ) {
                tempo2 = magma_sync_wtime( queue );
                if ( (solver_par->numiter) % solver_par->verbose == 0 ) {
                    solver_par->res_vec[(solver_par->numiter) / solver_par->verbose]
                            = (real_Double_t)nrmr;
                    solver_par->timing[(solver_par->numiter) / solver_par->verbose]
                            = (real_Double_t)tempo2 - tempo1;
                }
            }

            // check convergence or iteration limit
            if ( nrmr <= solver_par->atol ||
                nrmr/nrmb <= solver_par->rtol ) { 
                s = k + 1; // for the x-update outside the loop
                innerflag = 2;
                info = MAGMA_SUCCESS;
                break;
            }
        }

        // smoothing disabled
        if ( smoothing <= 0 && innerflag != 1 ) {
            // dbeta(1:s) = beta(1:s)
            // Q0
            magma_ssetvector_async( s, hbeta, 1, dbeta.dval, 1, queues[0] );

            // x = x + U(:,1:s) * beta(1:s)
            // Q0
            magmablas_sgemv( MagmaNoTrans, dU.num_rows, s, c_one, dU.dval, dU.ld, dbeta.dval, 1, c_one, x->dval, 1, queues[0] );
        }

        // check convergence or iteration limit or invalid result of inner loop
        if ( innerflag > 0 ) {
            break;
        }

        // computation of a new omega
//---------------------------------------
        // skp[0-2] = dskp[0-2]
        // Q2
        magma_sgetvector( 2, dskp.dval, 1, hskp, 1, queues[2] );
        // implicit sync Q2 --> skp = dskp

        // |t|
        nrmt = magma_ssqrt( MAGMA_S_REAL(hskp[0]) );
        
        // rho = abs((t' * r) / (|t| * |r|))
        rho = MAGMA_D_ABS( MAGMA_S_REAL(hskp[1]) / (nrmt * nrmr) );

        // om = (t' * r) / (|t| * |t|)
        om = hskp[1] / hskp[0]; 
        if ( rho < angle ) {
            om = (om * angle) / rho;
        }
//---------------------------------------
        if ( MAGMA_S_EQUAL(om, MAGMA_S_ZERO) ) {
            info = MAGMA_DIVERGENCE;
            break;
        }

        // sync Q1 --> v = r
        magma_queue_sync( queues[1] );

        // r = r - om * t
        // Q2
        magma_saxpy( dr.num_rows, -om, dt.dval, 1, dr.dval, 1, queues[2] );

        // x = x + om * v
        // Q0
        magma_saxpy( x->num_rows, om, dv.dval, 1, x->dval, 1, queues[0] );

        // smoothing disabled
        if ( smoothing <= 0 ) {
            // |r|
            // Q2
            nrmr = magma_snrm2( dr.num_rows, dr.dval, 1, queues[2] );           
            // implicit sync Q2 --> |r|

            // v = r
            // Q0
            magma_scopyvector_async( dr.num_rows, dr.dval, 1, dv.dval, 1, queues[0] );

            // new RHS for small systems
            // f = P' r
            // Q1
            magma_sgemvmdot_shfl( dP.num_rows, dP.num_cols, dP.dval, dr.dval, d1, d2, df.dval, queues[1] );

            // skp[4] = f(k)
            // Q1
            magma_sgetvector_async( 1, df.dval, 1, &hskp[4], 1, queues[1] );

            // c(k:s) = f(k:s)
            // Q1
            magma_scopyvector_async( s, df.dval, 1, dc.dval, 1, queues[1] );

            // c(k:s) = M(k:s,k:s) \ f(k:s)
            // Q1
            magma_strsv( MagmaLower, MagmaNoTrans, MagmaNonUnit, s, dM.dval, dM.ld, dc.dval, 1, queues[1] );

        // smoothing enabled
        } else {
            // smoothing operation
//---------------------------------------
            // t = rs - r
            // Q2
            magma_sidr_smoothing_1( drs.num_rows, drs.num_cols, drs.dval, dr.dval, dtt.dval, queues[2] );

            // t't
            // t'rs
            // Q2
            CHECK( magma_sgemvmdot_shfl( dt.ld, 2, dtt.dval, dtt.dval, d1, d2, &dskp.dval[2], queues[2] ));

            // skp[2-3] = dskp[2-3]
            // Q2
            magma_sgetvector( 2, &dskp.dval[2], 1, &hskp[2], 1, queues[2] );
            // implicit sync Q2 --> skp = dskp

            // gamma = (t' * rs) / (t' * t)
            gamma = hskp[3] / hskp[2];

            // rs = rs - gamma * (rs - r) 
            // Q2
            magma_saxpy( drs.num_rows, -gamma, dtt.dval, 1, drs.dval, 1, queues[2] );

            // xs = xs - gamma * (xs - x) 
            // Q0
            magma_sidr_smoothing_2( dxs.num_rows, dxs.num_cols, -gamma, x->dval, dxs.dval, queues[0] );

            // v = r
            // Q0
            magma_scopyvector_async( dr.num_rows, dr.dval, 1, dv.dval, 1, queues[0] );

            // new RHS for small systems
            // f = P' r
            // Q1
            magma_sgemvmdot_shfl( dP.num_rows, dP.num_cols, dP.dval, dr.dval, d1, d2, df.dval, queues[1] );

            // skp[4] = f(k)
            // Q1
            magma_sgetvector_async( 1, df.dval, 1, &hskp[4], 1, queues[1] );

            // c(k:s) = f(k:s)
            // Q1
            magma_scopyvector_async( s, df.dval, 1, dc.dval, 1, queues[1] );

            // |rs|
            // Q2
            nrmr = magma_snrm2( drs.num_rows, drs.dval, 1, queues[2] );           
            // implicit sync Q2 --> |r|

            // c(k:s) = M(k:s,k:s) \ f(k:s)
            // Q1
            magma_strsv( MagmaLower, MagmaNoTrans, MagmaNonUnit, s, dM.dval, dM.ld, dc.dval, 1, queues[1] );
//---------------------------------------
        }

        // store current timing and residual
        if ( solver_par->verbose > 0 ) {
            tempo2 = magma_sync_wtime( queue );
            magma_queue_sync( queue );
            if ( (solver_par->numiter) % solver_par->verbose == 0 ) {
                solver_par->res_vec[(solver_par->numiter) / solver_par->verbose]
                        = (real_Double_t)nrmr;
                solver_par->timing[(solver_par->numiter) / solver_par->verbose]
                        = (real_Double_t)tempo2 - tempo1;
            }
        }

        // check convergence or iteration limit
        if ( nrmr <= solver_par->atol ||
            nrmr/nrmb <= solver_par->rtol ) { 
            info = MAGMA_SUCCESS;
            break;
        }

        // sync Q0 --> v = r
        magma_queue_sync( queues[0] );
    }
    while ( solver_par->numiter + 1 <= solver_par->maxiter );

    // sync all queues
    for ( q = 0; q < nqueues; q++ ) {
        magma_queue_sync( queues[q] );
    }

    // smoothing enabled
    if ( smoothing > 0 ) {
        // x = xs
        magma_scopyvector_async( x->num_rows, dxs.dval, 1, x->dval, 1, queue );

        // r = rs
        magma_scopyvector_async( dr.num_rows, drs.dval, 1, dr.dval, 1, queue );
    }

cudaProfilerStop();

    // get last iteration timing
    tempo2 = magma_sync_wtime( queue );
    magma_queue_sync( queue );
    solver_par->runtime = (real_Double_t)tempo2 - tempo1;
//--------------STOP TIME----------------

    // get final stats
    solver_par->iter_res = nrmr;
    CHECK( magma_sresidualvec( A, b, *x, &dr, &residual, queue ));
    solver_par->final_res = residual;

    // set solver conclusion
    if ( info != MAGMA_SUCCESS && info != MAGMA_DIVERGENCE ) {
        if ( solver_par->init_res > solver_par->final_res ) {
            info = MAGMA_SLOW_CONVERGENCE;
        }
    }


cleanup:
    // free resources
    // sync all queues, destory additional queues
    magma_queue_sync( queues[0] );
    for ( q = 1; q < nqueues; q++ ) {
        magma_queue_sync( queues[q] );
        magma_queue_destroy( queues[q] );
    }

    // smoothing enabled
    if ( smoothing > 0 ) {
        drs.dval = NULL;  // needed because its pointer is redirected to dtt
        magma_smfree( &dxs, queue );
        magma_smfree( &drs, queue ); 
        magma_smfree( &dtt, queue );
    }
    dr.dval = NULL;       // needed because its pointer is redirected to dt
    dGcol.dval = NULL;    // needed because its pointer is redirected to dG
    magma_smfree( &dr, queue );
    magma_smfree( &dP, queue );
    magma_smfree( &dP1, queue );
    magma_smfree( &dG, queue );
    magma_smfree( &dGcol, queue );
    magma_smfree( &dU, queue );
    magma_smfree( &dM, queue );
    magma_smfree( &df, queue );
    magma_smfree( &dt, queue );
    magma_smfree( &dc, queue );
    magma_smfree( &dv, queue );
    magma_smfree( &dskp, queue );
    magma_smfree( &dalpha, queue );
    magma_smfree( &dbeta, queue );
    magma_free_pinned( hMdiag );
    magma_free_pinned( hskp );
    magma_free_pinned( halpha );
    magma_free_pinned( hbeta );
    magma_free( d1 );
    magma_free( d2 );

    solver_par->info = info;
    return info;
    /* magma_sidr_strms */
}