Tensor generator helpers (#93)

* TENONES: Add initial tenones support

* TENZEROS: Add initial tenzeros support

* TENDIAG: Add initial tendiag support

* SPTENDIAG: Add initial sptendiag support

Author: ntjohnson1

pyttb/__init__.py

@@ -15,13 +15,13 @@
 from pyttb.ktensor import ktensor
 from pyttb.pyttb_utils import *
 from pyttb.sptenmat import sptenmat
-from pyttb.sptensor import sptensor
+from pyttb.sptensor import sptendiag, sptensor
 from pyttb.sptensor3 import sptensor3
 from pyttb.sumtensor import sumtensor
 from pyttb.symktensor import symktensor
 from pyttb.symtensor import symtensor
 from pyttb.tenmat import tenmat
-from pyttb.tensor import tensor
+from pyttb.tensor import tendiag, tenones, tensor, tenzeros
 from pyttb.ttensor import ttensor
 from pyttb.tucker_als import tucker_als
 

pyttb/pyttb_utils.py

@@ -700,7 +700,7 @@ def tt_subscheck(subs, nargout=True):
         len(subs.shape) == 2
         and (np.isfinite(subs)).all()
         and issubclass(subs.dtype.type, np.integer)
-        and (subs > 0).all()
+        and (subs >= 0).all()
     ):
         ok = True
     else:

pyttb/sptensor.py

@@ -297,7 +297,7 @@ def from_aggregator(
 
         # Check for subscripts out of range
         for j, dim in enumerate(shape):
-            if subs.size > 0 and np.max(subs[:, j]) > dim:
+            if subs.size > 0 and np.max(subs[:, j]) >= dim:
                 assert False, "Subscript exceeds sptensor shape"
 
         if subs.size == 0:
@@ -2582,3 +2582,39 @@ def ttm(
         # TODO evaluate performance loss by casting into sptensor then tensor.
         #  I assume minimal since we are already using spare matrix representation
         return ttb.tensor.from_tensor_type(Ynt)
+
+
+def sptendiag(
+    elements: np.ndarray, shape: Optional[Tuple[int, ...]] = None
+) -> sptensor:
+    """
+    Creates a sparse tensor with elements along super diagonal
+    If provided shape is too small the tensor will be enlarged to accomodate
+
+    Parameters
+    ----------
+    elements: Elements to set along the diagonal
+    shape: Shape of resulting tensor
+
+    Returns
+    -------
+    Constructed tensor
+
+    Example
+    -------
+    >>> shape = (2,)
+    >>> values = np.ones(shape)
+    >>> X = ttb.sptendiag(values)
+    >>> Y = ttb.sptendiag(values, (2, 2))
+    >>> X.isequal(Y)
+    True
+    """
+    # Flatten provided elements
+    elements = np.ravel(elements)
+    N = len(elements)
+    if shape is None:
+        constructed_shape = (N,) * N
+    else:
+        constructed_shape = tuple(max(N, dim) for dim in shape)
+    subs = np.tile(np.arange(0, N).transpose(), (len(constructed_shape), 1)).transpose()
+    return sptensor.from_aggregator(subs, elements.reshape((N, 1)), constructed_shape)

pyttb/tensor.py

@@ -1835,6 +1835,80 @@ def __repr__(self):
     __str__ = __repr__
 
 
+def tenones(shape: Tuple[int, ...]) -> tensor:
+    """
+    Creates a tensor of all ones
+
+    Parameters
+    ----------
+    shape: Shape of resulting tensor
+
+    Returns
+    -------
+    Constructed tensor
+
+    Example
+    -------
+    >>> X = ttb.tenones((2,2))
+    """
+    return tensor.from_function(np.ones, shape)
+
+
+def tenzeros(shape: Tuple[int, ...]) -> tensor:
+    """
+    Creates a tensor of all zeros
+
+    Parameters
+    ----------
+    shape: Shape of resulting tensor
+
+    Returns
+    -------
+    Constructed tensor
+
+    Example
+    -------
+    >>> X = ttb.tenzeros((2,2))
+    """
+    return tensor.from_function(np.zeros, shape)
+
+
+def tendiag(elements: np.ndarray, shape: Optional[Tuple[int, ...]] = None) -> tensor:
+    """
+    Creates a tensor with elements along super diagonal
+    If provided shape is too small the tensor will be enlarged to accomodate
+
+    Parameters
+    ----------
+    elements: Elements to set along the diagonal
+    shape: Shape of resulting tensor
+
+    Returns
+    -------
+    Constructed tensor
+
+    Example
+    -------
+    >>> shape = (2,)
+    >>> values = np.ones(shape)
+    >>> X = ttb.tendiag(values)
+    >>> Y = ttb.tendiag(values, (2, 2))
+    >>> X.isequal(Y)
+    True
+    """
+    # Flatten provided elements
+    elements = np.ravel(elements)
+    N = len(elements)
+    if shape is None:
+        constructed_shape = (N,) * N
+    else:
+        constructed_shape = tuple(max(N, dim) for dim in shape)
+    X = tenzeros(constructed_shape)
+    subs = np.tile(np.arange(0, N).transpose(), (len(constructed_shape), 1))
+    X[subs] = elements
+    return X
+
+
 if __name__ == "__main__":
     import doctest  # pragma: no cover
 

tests/test_sptensor.py

@@ -1758,3 +1758,39 @@ def test_sptensor_from_sparse_matrix():
         Xnt = tt_to_sparse_matrix(sptensorCopy, mode, False)
         Ynt = tt_from_sparse_matrix(Xnt, sptensorCopy.shape, mode, 1)
         assert sptensorCopy.isequal(Ynt)
+
+
+def test_sptendiag():
+    N = 4
+    elements = np.arange(0, N)
+    exact_shape = [N] * N
+
+    # Inferred shape
+    X = ttb.sptendiag(elements)
+    for i in range(N):
+        diag_index = (i,) * N
+        assert (
+            X[diag_index] == i
+        ), f"Idx: {diag_index} expected: {i} got: {X[diag_index]}"
+
+    # Exact shape
+    X = ttb.sptendiag(elements, tuple(exact_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i
+
+    # Larger shape
+    larger_shape = exact_shape.copy()
+    larger_shape[0] += 1
+    X = ttb.sptendiag(elements, tuple(larger_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i
+
+    # Smaller Shape
+    smaller_shape = exact_shape.copy()
+    smaller_shape[0] -= 1
+    X = ttb.sptendiag(elements, tuple(smaller_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i

tests/test_tensor.py

@@ -1632,3 +1632,51 @@ def test_tensor_nvecs(sample_tensor_2way):
         "Greater than or equal to tensor.shape[n] - 1 eigenvectors requires cast to dense to solve"
         in str(record[0].message)
     )
+
+
+def test_tenones():
+    arbitrary_shape = (3, 3, 3)
+    ones_tensor = ttb.tenones(arbitrary_shape)
+    data_tensor = ttb.tensor.from_data(np.ones(arbitrary_shape))
+    assert np.equal(ones_tensor, data_tensor), "Tenones should match all ones tensor"
+
+
+def test_tenzeros():
+    arbitrary_shape = (3, 3, 3)
+    zeros_tensor = ttb.tenzeros(arbitrary_shape)
+    data_tensor = ttb.tensor.from_data(np.zeros(arbitrary_shape))
+    assert np.equal(zeros_tensor, data_tensor), "Tenzeros should match all zeros tensor"
+
+
+def test_tendiag():
+    N = 4
+    elements = np.arange(0, N)
+    exact_shape = [N] * N
+
+    # Inferred shape
+    X = ttb.tendiag(elements)
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i
+
+    # Exact shape
+    X = ttb.tendiag(elements, tuple(exact_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i
+
+    # Larger shape
+    larger_shape = exact_shape.copy()
+    larger_shape[0] += 1
+    X = ttb.tendiag(elements, tuple(larger_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i
+
+    # Smaller Shape
+    smaller_shape = exact_shape.copy()
+    smaller_shape[0] -= 1
+    X = ttb.tendiag(elements, tuple(smaller_shape))
+    for i in range(N):
+        diag_index = (i,) * N
+        assert X[diag_index] == i