Example #1
0
extern "C" magma_int_t
magma_scgs(
    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_CGS;
    solver_par->numiter = 0;
    solver_par->spmv_count = 0;
    
    // constants
    const float c_zero    = MAGMA_S_ZERO;
    const float c_one     = MAGMA_S_ONE;
    const float c_neg_one = MAGMA_S_NEG_ONE;
    
    // solver variables
    float nom0, r0, res=0, nomb;
    float rho, rho_l = c_one, alpha, beta;
    
    magma_int_t dofs = A.num_rows* b.num_cols;

    // GPU workspace
    magma_s_matrix r={Magma_CSR}, rt={Magma_CSR}, r_tld={Magma_CSR},
                    p={Magma_CSR}, q={Magma_CSR}, u={Magma_CSR}, v={Magma_CSR},  t={Magma_CSR},
                    p_hat={Magma_CSR}, q_hat={Magma_CSR}, u_hat={Magma_CSR}, v_hat={Magma_CSR};
    CHECK( magma_svinit( &r, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &rt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &r_tld,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &p, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &p_hat, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &q, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &q_hat, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &u, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &u_hat, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &v, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &v_hat, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &t, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));

    // solver setup
    CHECK(  magma_sresidualvec( A, b, *x, &r, &nom0, queue));
    magma_scopy( dofs, r.dval, 1, r_tld.dval, 1, queue );   

    solver_par->init_res = nom0;
            
    nomb = magma_snrm2( dofs, b.dval, 1, queue );
    if ( nomb == 0.0 ){
        nomb=1.0;
    }       
    if ( (r0 = nomb * solver_par->rtol) < ATOLERANCE ){
        r0 = ATOLERANCE;
    }
    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)nom0;
        solver_par->timing[0] = 0.0;
    }
    if ( nom0 < r0 ) {
        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++;
        
        rho = magma_sdot( dofs, r.dval, 1, r_tld.dval, 1, queue );
                                                            // rho = < r,r_tld>    
        if( magma_s_isnan_inf( rho ) ){
            info = MAGMA_DIVERGENCE;
            break;
        }
        
        if ( solver_par->numiter > 1 ) {                        // direction vectors
            beta = rho / rho_l;            
            magma_scopy( dofs, r.dval, 1, u.dval, 1, queue );          // u = r
            magma_saxpy( dofs,  beta, q.dval, 1, u.dval, 1, queue );     // u = u + beta q
            magma_sscal( dofs, beta, p.dval, 1, queue );                 // p = beta*p
            magma_saxpy( dofs, c_one, q.dval, 1, p.dval, 1, queue );      // p = q + beta*p
            magma_sscal( dofs, beta, p.dval, 1, queue );                 // p = beta*(q + beta*p)
            magma_saxpy( dofs, c_one, u.dval, 1, p.dval, 1, queue );     // p = u + beta*(q + beta*p)
        //u = r + beta*q;
        //p = u + beta*( q + beta*p );
        }
        else{
            magma_scopy( dofs, r.dval, 1, u.dval, 1, queue );          // u = r
            magma_scopy( dofs, r.dval, 1, p.dval, 1, queue );          // p = r
        }
        
        CHECK( magma_s_spmv( c_one, A, p, c_zero, v_hat, queue ));   // v = A p
        solver_par->spmv_count++;
        alpha = rho / magma_sdot( dofs, r_tld.dval, 1, v_hat.dval, 1, queue );
        magma_scopy( dofs, u.dval, 1, q.dval, 1, queue );              // q = u
        magma_saxpy( dofs,  -alpha, v_hat.dval, 1, q.dval, 1, queue );   // q = u - alpha v_hat
        
        magma_scopy( dofs, u.dval, 1, t.dval, 1, queue );             // t = q
        magma_saxpy( dofs,  c_one, q.dval, 1, t.dval, 1, queue );       // t = u + q


        CHECK( magma_s_spmv( c_one, A, t, c_zero, rt, queue ));   // t = A u_hat
        solver_par->spmv_count++;
        magma_saxpy( dofs,  c_neg_one*alpha, rt.dval, 1, r.dval, 1, queue );       // r = r -alpha*A u_hat
        magma_saxpy( dofs,  alpha, t.dval, 1, x->dval, 1, queue );      // x = x + alpha u_hat
        rho_l = rho;
        
        res = magma_snrm2( dofs, r.dval, 1, queue );
        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) res;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }

        if ( res/nomb <= solver_par->rtol || res <= solver_par->atol ){
            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 = res;
    solver_par->final_res = residual;

    if ( solver_par->numiter < solver_par->maxiter && info == MAGMA_SUCCESS ) {
        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) res;
                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->rtol*solver_par->init_res ||
            solver_par->iter_res < solver_par->atol ) {
            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) res;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        info = MAGMA_DIVERGENCE;
    }
    
cleanup:
    magma_smfree(&r, queue );
    magma_smfree(&rt, queue );
    magma_smfree(&r_tld, queue );
    magma_smfree(&p, queue );
    magma_smfree(&q, queue );
    magma_smfree(&u, queue );
    magma_smfree(&v, queue );
    magma_smfree(&t, queue );
    magma_smfree(&p_hat, queue );
    magma_smfree(&q_hat, queue );
    magma_smfree(&u_hat, queue );
    magma_smfree(&v_hat, queue );

    solver_par->info = info;
    return info;
}   /* magma_scgs */
Example #2
0
extern "C" magma_int_t
magma_sbicg(
    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_BICG;
    solver_par->numiter = 0;
    solver_par->spmv_count = 0;

    // some useful variables
    float c_zero = MAGMA_S_ZERO;
    float c_one  = MAGMA_S_ONE;
    float c_neg_one = MAGMA_S_NEG_ONE;
    
    magma_int_t dofs = A.num_rows * b.num_cols;

    // workspace
    magma_s_matrix r={Magma_CSR}, rt={Magma_CSR}, p={Magma_CSR}, pt={Magma_CSR}, 
                z={Magma_CSR}, zt={Magma_CSR}, q={Magma_CSR}, y={Magma_CSR}, 
                yt={Magma_CSR},  qt={Magma_CSR};
                
    // need to transpose the matrix
    magma_s_matrix AT={Magma_CSR}, Ah1={Magma_CSR}, Ah2={Magma_CSR};
    
    CHECK( magma_svinit( &r, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &rt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &p, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &pt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &q, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &qt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &y, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &yt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &z, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &zt,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));

    
    // solver variables
    float alpha, rho, beta, rho_new, ptq;
    float res, nomb, nom0, r0;

        // transpose the matrix
    magma_smtransfer( A, &Ah1, Magma_DEV, Magma_CPU, queue );
    magma_smconvert( Ah1, &Ah2, A.storage_type, Magma_CSR, queue );
    magma_smfree(&Ah1, queue );
    magma_smtransposeconjugate( Ah2, &Ah1, queue );
    magma_smfree(&Ah2, queue );
    Ah2.blocksize = A.blocksize;
    Ah2.alignment = A.alignment;
    magma_smconvert( Ah1, &Ah2, Magma_CSR, A.storage_type, queue );
    magma_smfree(&Ah1, queue );
    magma_smtransfer( Ah2, &AT, Magma_CPU, Magma_DEV, queue );
    magma_smfree(&Ah2, queue );
    
    // solver setup
    CHECK(  magma_sresidualvec( A, b, *x, &r, &nom0, queue));
    res = nom0;
    solver_par->init_res = nom0;
    magma_scopy( dofs, r.dval, 1, rt.dval, 1, queue );                  // rr = r
    rho_new = magma_sdot( dofs, rt.dval, 1, r.dval, 1, queue );             // rho=<rr,r>
    rho = alpha = MAGMA_S_MAKE( 1.0, 0. );

    nomb = magma_snrm2( dofs, b.dval, 1, queue );
    if ( nomb == 0.0 ){
        nomb=1.0;
    }       
    if ( (r0 = nomb * solver_par->rtol) < ATOLERANCE ){
        r0 = ATOLERANCE;
    }
    
    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;
    }
    if ( nom0 < r0 ) {
        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++;

        magma_scopy( dofs, r.dval, 1 , y.dval, 1, queue );             // y=r
        magma_scopy( dofs, y.dval, 1 , z.dval, 1, queue );             // z=y
        magma_scopy( dofs, rt.dval, 1 , yt.dval, 1, queue );           // yt=rt
        magma_scopy( dofs, yt.dval, 1 , zt.dval, 1, queue );           // zt=yt
        
        rho= rho_new;
        rho_new = magma_sdot( dofs, rt.dval, 1, z.dval, 1, queue );  // rho=<rt,z>
        if( magma_s_isnan_inf( rho_new ) ){
            info = MAGMA_DIVERGENCE;
            break;
        }
        
        if( solver_par->numiter==1 ){
            magma_scopy( dofs, z.dval, 1 , p.dval, 1, queue );           // yt=rt
            magma_scopy( dofs, zt.dval, 1 , pt.dval, 1, queue );           // zt=yt
        } else {
            beta = rho_new/rho;
            magma_sscal( dofs, beta, p.dval, 1, queue );                 // p = beta*p
            magma_saxpy( dofs, c_one , z.dval, 1 , p.dval, 1, queue );   // p = z+beta*p
            magma_sscal( dofs, MAGMA_S_CONJ(beta), pt.dval, 1, queue );   // pt = beta*pt
            magma_saxpy( dofs, c_one , zt.dval, 1 , pt.dval, 1, queue );  // pt = zt+beta*pt
        }
        CHECK( magma_s_spmv( c_one, A, p, c_zero, q, queue ));      // v = Ap
        CHECK( magma_s_spmv( c_one, AT, pt, c_zero, qt, queue ));   // v = Ap
        solver_par->spmv_count++;
        solver_par->spmv_count++;
        ptq = magma_sdot( dofs, pt.dval, 1, q.dval, 1, queue );
        alpha = rho_new /ptq;
        
        
        magma_saxpy( dofs, alpha, p.dval, 1 , x->dval, 1, queue );                // x=x+alpha*p
        magma_saxpy( dofs, c_neg_one * alpha, q.dval, 1 , r.dval, 1, queue );     // r=r+alpha*q
        magma_saxpy( dofs, c_neg_one * MAGMA_S_CONJ(alpha), qt.dval, 1 , rt.dval, 1, queue );     // r=r+alpha*q

        res = magma_snrm2( dofs, r.dval, 1, queue );

        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) res;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }

        if ( res/nomb <= solver_par->rtol || res <= solver_par->atol ){
            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 = res;
    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) res;
                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->rtol*solver_par->init_res ||
            solver_par->iter_res < solver_par->atol ) {
            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) res;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }
        info = MAGMA_DIVERGENCE;
    }
    
cleanup:
    magma_smfree(&r, queue );
    magma_smfree(&rt, queue );
    magma_smfree(&p, queue );
    magma_smfree(&pt, queue );
    magma_smfree(&q, queue );
    magma_smfree(&qt, queue );
    magma_smfree(&y, queue );
    magma_smfree(&yt, queue );
    magma_smfree(&z, queue );
    magma_smfree(&zt, queue );
    magma_smfree(&AT, queue );
    magma_smfree(&Ah1, queue );
    magma_smfree(&Ah2, queue );

    solver_par->info = info;
    return info;
}   /* magma_sbicg */
Example #3
0
extern "C" magma_int_t
magma_sbicgstab_merge(
    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_BICGSTAB;
    solver_par->numiter = 0;
    solver_par->spmv_count = 0;

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

    // workspace
    magma_s_matrix r={Magma_CSR}, rr={Magma_CSR}, p={Magma_CSR}, v={Magma_CSR}, 
    s={Magma_CSR}, t={Magma_CSR}, d1={Magma_CSR}, d2={Magma_CSR};
    CHECK( magma_svinit( &r, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &rr,Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &p, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &v, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &s, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &t, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &d1, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));
    CHECK( magma_svinit( &d2, Magma_DEV, A.num_rows, b.num_cols, c_zero, queue ));

    
    // solver variables
    float alpha, beta, omega, rho_old, rho_new;
    float betanom, nom0, r0, res, nomb;
    res=0;
    //float nom;
    //float den;

    // solver setup
    CHECK(  magma_sresidualvec( A, b, *x, &r, &nom0, queue));
    magma_scopy( dofs, r.dval, 1, rr.dval, 1, queue );                  // rr = 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. );
    solver_par->init_res = nom0;

    CHECK( magma_s_spmv( c_one, A, r, c_zero, v, queue ));              // z = A r
    //den = MAGMA_S_REAL( magma_sdot( dofs, v.dval, 1, r.dval, 1), queue ); // den = z' * r

    nomb = magma_snrm2( dofs, b.dval, 1, queue );
    if ( nomb == 0.0 ){
        nomb=1.0;
    }       
    if ( (r0 = nomb * solver_par->rtol) < ATOLERANCE ){
        r0 = ATOLERANCE;
    }
    
    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;
    }
    if ( nomb < r0 ) {
        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++;
        rho_old = rho_new;                                    // rho_old=rho

        rho_new = magma_sdot( dofs, rr.dval, 1, r.dval, 1, queue );  // rho=<rr,r>
        beta = rho_new/rho_old * alpha/omega;   // beta=rho/rho_old *alpha/omega
        if( magma_s_isnan_inf( beta ) ){
            info = MAGMA_DIVERGENCE;
            break;
        }
        
        // p = r + beta * ( p - omega * v )
        magma_sbicgstab_1(  
        r.num_rows, 
        r.num_cols, 
        beta,
        omega,
        r.dval, 
        v.dval,
        p.dval,
        queue );

        CHECK( magma_s_spmv( c_one, A, p, c_zero, v, queue ));      // v = Ap
        solver_par->spmv_count++;
        //alpha = rho_new / tmpval;
        alpha = rho_new /magma_sdot( dofs, rr.dval, 1, v.dval, 1, queue );
        if( magma_s_isnan_inf( alpha ) ){
            info = MAGMA_DIVERGENCE;
            break;
        }
        // s = r - alpha v
        magma_sbicgstab_2(  
        r.num_rows, 
        r.num_cols, 
        alpha,
        r.dval,
        v.dval,
        s.dval, 
        queue );

        CHECK( magma_s_spmv( c_one, A, s, c_zero, t, queue ));       // t=As
        solver_par->spmv_count++;
        omega = magma_sdot( dofs, t.dval, 1, s.dval, 1, queue )   // omega = <s,t>/<t,t>
                   / magma_sdot( dofs, t.dval, 1, t.dval, 1, queue );
                        
        // x = x + alpha * p + omega * s
        // r = s - omega * t
        magma_sbicgstab_3(  
        r.num_rows, 
        r.num_cols, 
        alpha,
        omega,
        p.dval,
        s.dval,
        t.dval,
        x->dval,
        r.dval,
        queue );

        res = betanom = magma_snrm2( dofs, r.dval, 1, queue );

        //nom = betanom*betanom;

        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) res;
                solver_par->timing[(solver_par->numiter)/solver_par->verbose]
                        = (real_Double_t) tempo2-tempo1;
            }
        }

        if ( res/nomb <= solver_par->rtol || res <= solver_par->atol ){
            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 = res;
    solver_par->final_res = residual;

    if ( solver_par->numiter < solver_par->maxiter && info == MAGMA_SUCCESS ) {
        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->rtol*solver_par->init_res ||
            solver_par->iter_res < solver_par->atol ) {
            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(&r, queue );
    magma_smfree(&rr, queue );
    magma_smfree(&p, queue );
    magma_smfree(&v, queue );
    magma_smfree(&s, queue );
    magma_smfree(&t, queue );
    magma_smfree(&d1, queue );
    magma_smfree(&d2, queue );

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