ValueError: can only convert an array of size 1 to a Python scalar

[futtery]

Hi,I have found a problem in building the tree when dealing with some datasets, but I don't know why. When I run the initial code as following,

# Construct forest
forest = []
while len(forest) < num_trees:
# Select random subsets of points uniformly
ixs = np.random.choice(n, size=sample_size_range,
replace=False)
# Add sampled trees to forest
trees = [rrcf.RCTree(X[ix], index_labels=ix)
for ix in ixs]
forest.extend(trees)

the error happens ,and it display like this .

ValueError Traceback (most recent call last)
in
116 replace=False)
117 # Add sampled trees to forest
--> 118 trees = [rrcf.RCTree(X[ix], index_labels=ix)
119 for ix in ixs]
120 forest.extend(trees)

in (.0)
116 replace=False)
117 # Add sampled trees to forest
--> 118 trees = [rrcf.RCTree(X[ix], index_labels=ix)
119 for ix in ixs]
120 forest.extend(trees)

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in init(self, X, index_labels, precision, random_state)
104 # Create RRC Tree
105 S = np.ones(n, dtype=np.bool)
--> 106 self._mktree(X, S, N, I, parent=self)
107 # Remove parent of root
108 self.root.u = None

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in _mktree(self, X, S, N, I, parent, side, depth)
196 if S2.sum() > 1:
197 # Recursively construct tree on S2
--> 198 self._mktree(X, S2, N, I, parent=branch, side='r', depth=depth)
199 # Otherwise...
200 else:

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in _mktree(self, X, S, N, I, parent, side, depth)
174 if S1.sum() > 1:
175 # Recursively construct tree on S1
--> 176 self._mktree(X, S1, N, I, parent=branch, side='l', depth=depth)
177 # Otherwise...
178 else:

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in _mktree(self, X, S, N, I, parent, side, depth)
174 if S1.sum() > 1:
175 # Recursively construct tree on S1
--> 176 self._mktree(X, S1, N, I, parent=branch, side='l', depth=depth)
177 # Otherwise...
178 else:

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in _mktree(self, X, S, N, I, parent, side, depth)
174 if S1.sum() > 1:
175 # Recursively construct tree on S1
--> 176 self._mktree(X, S1, N, I, parent=branch, side='l', depth=depth)
177 # Otherwise...
178 else:

~/anaconda3/lib/python3.8/site-packages/rrcf/rrcf.py in _mktree(self, X, S, N, I, parent, side, depth)
200 else:
201 # Create a leaf node from isolated point
--> 202 i = np.asscalar(np.flatnonzero(S2))
203 leaf = Leaf(i=i, d=depth, u=branch, x=X[i, :], n=N[i])
204 # Link leaf node to parent

<array_function internals> in asscalar(*args, **kwargs)

~/anaconda3/lib/python3.8/site-packages/numpy/lib/type_check.py in asscalar(a)
579 24
580 """
--> 581 return a.item()
582
583 #-----------------------------------------------------------------------------

ValueError: can only convert an array of size 1 to a Python scalar

However, when I try to run the X[ix] and build again ,it run.

[AtanasGruev]

Hello, although the issue is already dated and the problem might have been solved by the author, I'd like to point out a possible hint for future users. Most probably the cause is that either S1 or S2 in the _cut() method is computed to be a False-only mask; in other words, either the left or right split resulting from the operation (X[:, q] <= p) is empty.

Check whether X in the constructor

rrcf/rrcf/rrcf.py

Line 84 in 1795a1b

X = np.around(X, decimals=precision)

and p in the _cut() method

rrcf/rrcf/rrcf.py

Line 156 in 1795a1b

p = self.rng.uniform(xmin[q], xmax[q])

are both cast to the same type / dtype. I had the case where e.g. the samples used to initialize instances of RCTree had dtype np.float32 whereas p was of dtype np.float64. Similar discrepancies have been reported w.r.t. numpy broadcasting, refer to e.g. numpy issue #10982.