diff --git a/pyttb/ktensor.py b/pyttb/ktensor.py index 622807fa..58b068d3 100644 --- a/pyttb/ktensor.py +++ b/pyttb/ktensor.py @@ -495,25 +495,27 @@ def from_vector(cls, data, shape, contains_weights): def arrange(self, weight_factor=None, permutation=None): """ - Arrange the rank-1 components of a :class:`pyttb.ktensor`. The - columns are permuted in place, so you must make a copy before calling - this method if you want to store the original :class:`pyttb.ktensor`. - One of the parameters, either `weight_factor` or `permutation` - must be passed, and passing both parameters leads to an error. + Arrange the rank-1 components of a :class:`pyttb.ktensor` in place. + If `permutation` is passed, the columns of `self.factor_matrices` are + arranged using the provided permutation, so you must make a copy + before calling this method if you want to store the original + :class:`pyttb.ktensor`. If `weight_factor` is passed, then the values + in `self.weights` are absorbed into + `self.factor_matrices[weight_factor]`. If no parameters are passed, + then the columns of `self.factor_matrices` are normalized and then + permuted such that the resulting `self.weights` are sorted by + magnitude, greatest to least. Passing both parameters leads to an + error. Parameters ---------- weight_factor: int, optional - The index of the factor that the weights will be absorbed into - permutation: :class:`tuple`, :class:`list`, :class:`numpy.ndarray`, optional + The index of the factor matrix that the weights will be absorbed into. + permutation: :class:`tuple`, :class:`list`, or :class:`numpy.ndarray`, optional The new order of the components of the :class:`pyttb.ktensor` into which to permute. The permutation must be of length equal to - the number of components of the :class:`pyttb.ktensor`, N, and - must be a permutation of 1 to N. - - Returns - ------- - :class:`pyttb.ktensor` + the number of components of the :class:`pyttb.ktensor`, `self.ncomponents` + and must be a permutation of [0,...,`self.ncomponents`-1]. Examples -------- @@ -546,13 +548,40 @@ def arrange(self, weight_factor=None, permutation=None): factor_matrices[1] = [[6. 5.] [8. 7.]] - """ + Normalize and permute columns such that `weights` are sorted in + decreasing order: + + >>> K.arrange() + >>> print(K) # doctest: +ELLIPSIS + ktensor of shape 2 x 2 + weights=[89.4427... 27.2029...] + factor_matrices[0] = + [[0.4472... 0.3162...] + [0.8944... 0.9486...]] + factor_matrices[1] = + [[0.6... 0.5812...] + [0.8... 0.8137...]] + + Absorb the weights into the second factor: + + >>> K.arrange(weight_factor=1) + >>> print(K) # doctest: +ELLIPSIS + ktensor of shape 2 x 2 + weights=[1. 1.] + factor_matrices[0] = + [[0.4472... 0.3162...] + [0.8944... 0.9486...]] + factor_matrices[1] = + [[53.6656... 15.8113...] + [71.5541... 22.1359...]] + """ if permutation is not None and weight_factor is not None: assert ( False ), "Weighting and permuting the ktensor at the same time is not allowed." + # arrange columns of factor matrices using the permutation provided if permutation is not None and isinstance( permutation, (tuple, list, np.ndarray) ): @@ -566,8 +595,8 @@ def arrange(self, weight_factor=None, permutation=None): False ), "Number of elements in permutation does not match number of components in ktensor." - # TODO there is a relationship here between normalize and arrange that repeats tasks. Can this be made to be more efficient? - # ensure that factor matrices are normalized + # TODO there is a relationship here between normalize and arrange that repeats tasks. + # Can this be made to be more efficient? ensure that factor matrices are normalized self.normalize() # sort @@ -576,16 +605,13 @@ def arrange(self, weight_factor=None, permutation=None): for i in range(self.ndims): self.factor_matrices[i] = self.factor_matrices[i][:, p] - # TODO is this necessary? Matlab only absorbs into the last factor, not factor N as is documented - # absorb weight into one factor if requested + # absorb the weights into one factor, optional if weight_factor is not None: - pass - # if exist('foo','var') - # r = length(X.lambda); - # X.u{end} = full(X.u{end} * spdiags(X.lambda,0,r,r)); - # X.lambda = ones(size(X.lambda)); - # end - return self + r = len(self.weights) + self.factor_matrices[weight_factor] *= self.weights + self.weights = np.ones_like(self.weights) + + return def copy(self): """ @@ -1260,7 +1286,7 @@ def norm(self): def normalize(self, weight_factor=None, sort=False, normtype=2, mode=None): """ Normalize the columns of the factor matrices of a - :class:`pyttb.ktensor`. + :class:`pyttb.ktensor` in place. Parameters ---------- @@ -1273,7 +1299,7 @@ def normalize(self, weight_factor=None, sort=False, normtype=2, mode=None): normtype: {non-negative int, -1, -2, np.inf, -np.inf}, optional Order of the norm (see :func:`numpy.linalg.norm` for possible values). - mode: {int, None}, optional + mode: int, optional Index of factor matrix to normalize. A value of `None` means normalize all factor matrices. @@ -1284,7 +1310,7 @@ def normalize(self, weight_factor=None, sort=False, normtype=2, mode=None): Examples -------- >>> K = ttb.ktensor.from_function(np.ones, (2, 3, 4), 2) - >>> print(K.normalize()) # doctest: +ELLIPSIS + >>> print(K.normalize()) # doctest: +ELLIPSIS ktensor of shape 2 x 3 x 4 weights=[4.898... 4.898...] factor_matrices[0] = @@ -1310,7 +1336,7 @@ def normalize(self, weight_factor=None, sort=False, normtype=2, mode=None): 1.0 / tmp * self.factor_matrices[mode][:, r] ) self.weights[r] = self.weights[r] * tmp - return + return self else: assert ( False @@ -1349,7 +1375,7 @@ def normalize(self, weight_factor=None, sort=False, normtype=2, mode=None): if self.ncomponents > 1: # indices of srting in descending order p = np.argsort(self.weights)[::-1] - self = self.arrange(permutation=p) + self.arrange(permutation=p) return self