Example #1
0
def norm(x, p=2, axis=None):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.
    p : int or str, optional
        The type of norm.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    # Norms for scalars same as absolute value.
    if p == 1 or x.is_scalar():
        return pnorm(x, 1, axis)
    elif p == "inf":
        return pnorm(x, 'inf', axis)
    elif p == "nuc":
        return normNuc(x)
    elif p == "fro":
        return pnorm(x, 2, axis)
    elif p == 2:
        if axis is None and x.is_matrix():
            return sigma_max(x)
        else:
            return pnorm(x, 2, axis)
    else:
        return pnorm(x, p, axis)
Example #2
0
def norm(x, p=2):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.
    p : int or str, optional
        The type of norm.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    if p == 1:
        return norm1(x)
    elif p == "inf":
        return normInf(x)
    elif p == "nuc":
        return normNuc(x)
    elif p == "fro":
        return norm2(x)
    elif p == 2:
        if x.is_matrix():
            return sigma_max(x)
        else:
            return norm2(x)
    else:
        raise Exception("Invalid value %s for p." % p)
Example #3
0
File: norm.py Project: giserh/cvxpy
def norm(x, p=2, axis=None):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.
    p : int or str, optional
        The type of norm.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    if p == 1:
        return pnorm(x, 1, axis)
    elif p == "inf":
        return pnorm(x, 'inf', axis)
    elif p == "nuc":
        return normNuc(x)
    elif p == "fro":
        return pnorm(x, 2, axis)
    elif p == 2:
        if x.is_matrix():
            return sigma_max(x)
        else:
            return pnorm(x, 2, axis)
    else:
        return pnorm(x, p, axis)
Example #4
0
def norm(x, p=2):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.
    p : int or str, optional
        The type of norm.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    if p == 1:
        return norm1(x)
    elif p == "inf":
        return normInf(x)
    elif p == "nuc":
        return normNuc(x)
    elif p == "fro":
        return norm2(x)
    elif p == 2:
        if x.is_matrix():
            return sigma_max(x)
        else:
            return norm2(x)
    else:
        raise Exception("Invalid value %s for p." % p)
Example #5
0
def norm(x, p=2, axis=None):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.  If `x` is 2D and `axis` is None,
        this function constructs a matrix norm.
    p : int or str, optional
        The type of norm. Valid options include any positive integer,
        'fro' (for frobenius), 'nuc' (sum of singular values), np.inf or
        'inf' (infinity norm).
    axis : The axis along which to apply the norm, if any.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    # matrix norms take precedence
    num_nontrivial_idxs = sum([d > 1 for d in x.shape])
    if axis is None and x.ndim == 2:
        if p == 1:  # matrix 1-norm
            return cvxpy.atoms.max(norm1(x, axis=0))
        # Frobenius norm
        elif p == 'fro' or (p == 2 and num_nontrivial_idxs == 1):
            return pnorm(vec(x), 2)
        elif p == 2:  # matrix 2-norm is largest singular value
            return sigma_max(x)
        elif p == 'nuc':  # the nuclear norm (sum of singular values)
            return normNuc(x)
        elif p in [np.inf, "inf", "Inf"]:  # the matrix infinity-norm
            return cvxpy.atoms.max(norm1(x, axis=1))
        else:
            raise RuntimeError('Unsupported matrix norm.')
    else:
        if p == 1 or x.is_scalar():
            return norm1(x, axis=axis)
        elif p in [np.inf, "inf", "Inf"]:
            return norm_inf(x, axis)
        else:
            return pnorm(x, p, axis)
Example #6
0
def norm(x, p=2, axis=None):
    """Wrapper on the different norm atoms.

    Parameters
    ----------
    x : Expression or numeric constant
        The value to take the norm of.
    p : int or str, optional
        The type of norm.

    Returns
    -------
    Expression
        An Expression representing the norm.
    """
    x = Expression.cast_to_const(x)
    # matrix norms take precedence
    if axis is None and x.ndim == 2:
        if p == 1:  # matrix 1-norm
            return cvxpy.atoms.max(norm1(x, axis=0))
        elif p == 2:  # matrix 2-norm is largest singular value
            return sigma_max(x)
        elif p == 'nuc':  # the nuclear norm (sum of singular values)
            return normNuc(x)
        elif p == 'fro':  # Frobenius norm
            return pnorm(vec(x), 2)
        elif p in [np.inf, "inf", "Inf"]:  # the matrix infinity-norm
            return cvxpy.atoms.max(norm1(x, axis=1))
        else:
            raise RuntimeError('Unsupported matrix norm.')
    else:
        if p == 1 or x.is_scalar():
            return norm1(x, axis=axis)
        elif p in [np.inf, "inf", "Inf"]:
            return norm_inf(x, axis)
        else:
            return pnorm(x, p, axis)