# scipy.spatial.distance.is_valid_y

scipy.spatial.distance.is_valid_y(y, warning=False, throw=False, name=None)

  Return True if the input array is a valid condensed distance matrix.

  Condensed distance matrices must be 1-dimensional numpy arrays. Their length must be a binomial coefficient \({n \choose 2}\) for some positive integer n.

  Parameters:
    y array_like

      The condensed distance matrix.

    warning bool, optional

      Invokes a warning if the variable passed is not a valid condensed distance matrix. The warning message explains why the distance matrix is not valid. name is used when referencing the offending variable.

    throw bool, optional

      Throws an exception if the variable passed is not a valid condensed distance matrix.

    name bool, optional

      Used when referencing the offending variable in the warning or exception message.

  Returns:
    bool

      True if the input array is a valid condensed distance matrix, False otherwise.

  Examples

      >>> from scipy.spatial.distance import is_valid_y

  This vector is a valid condensed distance matrix. The length is 6, which corresponds to `n = 4`, since `4*(4 - 1)/2` is 6.

      >>> v = [1.0, 1.2, 1.0, 0.5, 1.3, 0.9]
      >>> is_valid_y(v)
      True

  An input vector with length, say, 7, is not a valid condensed distance matrix.

      >>> is_valid_y([1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7])
      False