Module « scipy.linalg »

Fonction get_blas_funcs - module scipy.linalg

Signature de la fonction get_blas_funcs

def get_blas_funcs(names, arrays=(), dtype=None, ilp64=False) 

Description

get_blas_funcs.__doc__

Return available BLAS function objects from names.

    Arrays are used to determine the optimal prefix of BLAS routines.

    Parameters
    ----------
    names : str or sequence of str
        Name(s) of BLAS functions without type prefix.

    arrays : sequence of ndarrays, optional
        Arrays can be given to determine optimal prefix of BLAS
        routines. If not given, double-precision routines will be
        used, otherwise the most generic type in arrays will be used.

    dtype : str or dtype, optional
        Data-type specifier. Not used if `arrays` is non-empty.

    ilp64 : {True, False, 'preferred'}, optional
        Whether to return ILP64 routine variant.
        Choosing 'preferred' returns ILP64 routine if available,
        and otherwise the 32-bit routine. Default: False

    Returns
    -------
    funcs : list
        List containing the found function(s).


    Notes
    -----
    This routine automatically chooses between Fortran/C
    interfaces. Fortran code is used whenever possible for arrays with
    column major order. In all other cases, C code is preferred.

    In BLAS, the naming convention is that all functions start with a
    type prefix, which depends on the type of the principal
    matrix. These can be one of {'s', 'd', 'c', 'z'} for the NumPy
    types {float32, float64, complex64, complex128} respectively.
    The code and the dtype are stored in attributes `typecode` and `dtype`
    of the returned functions.

    Examples
    --------
    >>> import scipy.linalg as LA
    >>> rng = np.random.default_rng()
    >>> a = rng.random((3,2))
    >>> x_gemv = LA.get_blas_funcs('gemv', (a,))
    >>> x_gemv.typecode
    'd'
    >>> x_gemv = LA.get_blas_funcs('gemv',(a*1j,))
    >>> x_gemv.typecode
    'z'