Implemented dpctl.tensor.meshgrid and tests

Author: ndgrigorian

dpctl/tensor/__init__.py

@@ -31,6 +31,7 @@
     full,
     full_like,
     linspace,
+    meshgrid,
     ones,
     ones_like,
     tril,
@@ -87,4 +88,5 @@
     "from_dlpack",
     "tril",
     "triu",
+    "meshgrid",
 ]

dpctl/tensor/_ctors.py

@@ -1198,3 +1198,53 @@ def triu(X, k=0):
         hev.wait()
 
     return res
+
+
+def meshgrid(*arrays, indexing="xy"):
+
+    """
+    meshgrid(*arrays, indexing="xy") -> list[usm_ndarray]
+
+    Creates list of `usm_ndarray` coordinate matrices from vectors.
+
+    Args:
+        arrays: arbitrary number of one-dimensional `USM_ndarray` objects.
+            If vectors are not of the same data type,
+            or are not one-dimensional, raises `ValueError.`
+        indexing: Cartesian (`xy`) or matrix (`ij`) indexing of output.
+            For a set of `n` vectors with lengths X0, X1, X2, ...
+            Cartesian indexing results in arrays of shape
+            (X1, X0, X2, ...)
+            matrix indexing results in arrays of shape
+            (X0, X1, X2, ...)
+            Default: `xy`.
+    """
+    for array in arrays:
+        if not isinstance(array, dpt.usm_ndarray):
+            raise TypeError(
+                f"Expected instance of dpt.usm_ndarray, got {type(array)}."
+            )
+        if array.ndim != 1:
+            raise ValueError("All arrays must be one-dimensional.")
+    if len(set([array.dtype for array in arrays])) > 1:
+        raise ValueError("All arrays must be of the same numeric data type.")
+    if indexing not in ["xy", "ij"]:
+        raise ValueError(
+            "Unrecognized indexing keyword value, expecting 'xy' or 'ij.'"
+        )
+    n = len(arrays)
+    sh = (-1,) + (1,) * (n - 1)
+
+    res = []
+    if n > 1 and indexing == "xy":
+        res.append(dpt.reshape(arrays[0], (1, -1) + sh[2:], copy=True))
+        res.append(dpt.reshape(arrays[1], sh, copy=True))
+        arrays, sh = arrays[2:], sh[-2:] + sh[:-2]
+
+    for array in arrays:
+        res.append(dpt.reshape(array, sh, copy=True))
+        sh = sh[-1:] + sh[:-1]
+
+    output = dpt.broadcast_arrays(*res)
+
+    return output

dpctl/tests/test_usm_ndarray_ctor.py

@@ -1427,6 +1427,30 @@ def test_tril_order_k(order, k):
     assert np.array_equal(Ynp, dpt.asnumpy(Y))
 
 
+def test_meshgrid():
+    try:
+        q = dpctl.SyclQueue()
+    except dpctl.SyclQueueCreationError:
+        pytest.skip("Queue could not be created")
+    X = dpt.usm_ndarray((5,), sycl_queue=q)
+    Y = dpt.usm_ndarray((3,), sycl_queue=q)
+    Z = dpt.meshgrid(X, Y)
+    Znp = np.meshgrid(dpt.asnumpy(X), dpt.asnumpy(Y))
+    n = len(Z)
+    assert n == len(Znp)
+    for i in range(n):
+        assert np.array_equal(dpt.asnumpy(Z[i]), Znp[i])
+    # dimension > 1 must raise ValueError
+    with pytest.raises(ValueError):
+        dpt.meshgrid(dpt.usm_ndarray((4, 4)))
+    # unknown indexing kwarg must raise ValueError
+    with pytest.raises(ValueError):
+        dpt.meshgrid(X, indexing="ji")
+    # input arrays with different data types must raise ValueError
+    with pytest.raises(ValueError):
+        dpt.meshgrid(X, dpt.asarray(Y, dtype="b1"))
+
+
 def test_common_arg_validation():
     order = "I"
     # invalid order must raise ValueError
@@ -1463,3 +1487,5 @@ def test_common_arg_validation():
         dpt.tril(X)
     with pytest.raises(TypeError):
         dpt.triu(X)
+    with pytest.raises(TypeError):
+        dpt.meshgrid(X)