[backport] Update array_api

cupy/array_api/__init__.py

@@ -128,7 +128,9 @@
     "The cupy.array_api submodule is still experimental. See NEP 47.", stacklevel=2
 )
 
-__all__ = []
+__array_api_version__ = "2021.12"
+
+__all__ = ["__array_api_version__"]
 
 from ._constants import e, inf, nan, pi
 

cupy/array_api/_manipulation_functions.py

@@ -52,6 +52,7 @@ def permute_dims(x: Array, /, axes: Tuple[int, ...]) -> Array:
     return Array._new(np.transpose(x._array, axes))
 
 
+# Note: the optional argument is called 'shape', not 'newshape'
 def reshape(x: Array, /, shape: Tuple[int, ...]) -> Array:
     """
     Array API compatible wrapper for :py:func:`np.reshape <numpy.reshape>`.

cupy/array_api/linalg.py

@@ -378,7 +378,18 @@ def trace(x: Array, /, *, offset: int = 0) -> Array:
 def vecdot(x1: Array, x2: Array, /, *, axis: int = -1) -> Array:
     if x1.dtype not in _numeric_dtypes or x2.dtype not in _numeric_dtypes:
         raise TypeError('Only numeric dtypes are allowed in vecdot')
-    return tensordot(x1, x2, axes=((axis,), (axis,)))
+    ndim = max(x1.ndim, x2.ndim)
+    x1_shape = (1,)*(ndim - x1.ndim) + tuple(x1.shape)
+    x2_shape = (1,)*(ndim - x2.ndim) + tuple(x2.shape)
+    if x1_shape[axis] != x2_shape[axis]:
+        raise ValueError("x1 and x2 must have the same size along the given axis")
+
+    x1_, x2_ = np.broadcast_arrays(x1._array, x2._array)
+    x1_ = np.moveaxis(x1_, axis, -1)
+    x2_ = np.moveaxis(x2_, axis, -1)
+
+    res = x1_[..., None, :] @ x2_[..., None]
+    return Array._new(res[..., 0, 0])
 
 
 # Note: the name here is different from norm(). The array API norm is split