FLA_Tevd_compute_scaling.c File Reference

(r)

Functions
FLA_Error	FLA_Tevd_compute_scaling_ops (int m_A, float *buff_d, int inc_d, float *buff_e, int inc_e, float *sigma)
FLA_Error	FLA_Tevd_compute_scaling_opd (int m_A, double *buff_d, int inc_d, double *buff_e, int inc_e, double *sigma)

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Function Documentation

FLA_Error FLA_Tevd_compute_scaling_opd	(	int	m_A,
		double *	buff_d,
		int	inc_d,
		double *	buff_e,
		int	inc_e,
		double *	sigma
	)

References bli_d1(), FLA_Mach_params_opd(), and FLA_Norm1_tridiag_opd().

{
    double one   = bli_d1();
    double three = 3.0;
    double norm;
    double eps2;
    double safmin;
    double safmax;
    double ssfmin;
    double ssfmax;

    // Query some constants.
    eps2   = FLA_Mach_params_opd( FLA_MACH_EPS2 );
    safmin = FLA_Mach_params_opd( FLA_MACH_SFMIN );
    safmax = one / safmin;

    // Compute the acceptable range for the 1-norm;
    ssfmax = sqrt( safmax ) / three;
    ssfmin = sqrt( safmin ) / eps2;

    // Compute the 1-norm of the tridiagonal matrix.
    FLA_Norm1_tridiag_opd( m_A,
                           buff_d, inc_d,
                           buff_e, inc_e,
                           &norm );

    // Compute sigma accordingly if norm is outside of the range.
    if ( norm > ssfmax )
    {
        *sigma = ssfmax / norm;
    }
    else if ( norm < ssfmin )
    {
        *sigma = ssfmin / norm;
    }
    else
    {
        *sigma = one;
    }

    return FLA_SUCCESS;
}

FLA_Error FLA_Tevd_compute_scaling_ops	(	int	m_A,
		float *	buff_d,
		int	inc_d,
		float *	buff_e,
		int	inc_e,
		float *	sigma
	)

References bli_s1(), FLA_Mach_params_ops(), and FLA_Norm1_tridiag_ops().

{
    float  one   = bli_s1();
    float  three = 3.0F;
    float  norm;
    float  eps2;
    float  safmin;
    float  safmax;
    float  ssfmin;
    float  ssfmax;

    // Query some constants.
    eps2   = FLA_Mach_params_ops( FLA_MACH_EPS2 );
    safmin = FLA_Mach_params_ops( FLA_MACH_SFMIN );
    safmax = one / safmin;

    // Compute the acceptable range for the 1-norm;
    ssfmax = sqrt( safmax ) / three;
    ssfmin = sqrt( safmin ) / eps2;

    // Compute the 1-norm of the tridiagonal matrix.
    FLA_Norm1_tridiag_ops( m_A,
                           buff_d, inc_d,
                           buff_e, inc_e,
                           &norm );

    // Compute sigma accordingly if norm is outside of the range.
    if ( norm > ssfmax )
    {
        *sigma = ssfmax / norm;
    }
    else if ( norm < ssfmin )
    {
        *sigma = ssfmin / norm;
    }
    else
    {
        *sigma = one;
    }

    return FLA_SUCCESS;
}