Add dpnp.sinc function to the interface

Author: antonwolfy

dpnp/dpnp_iface_mathematical.py

@@ -130,6 +130,7 @@
     "round",
     "sign",
     "signbit",
+    "sinc",
     "subtract",
     "sum",
     "trapezoid",
@@ -3749,6 +3750,75 @@ def real_if_close(a, tol=100):
 )
 
 
+_SINC_DOCSTRING = r"""
+Return the normalized sinc function.
+
+The sinc function is equal to :math:`\sin(\pi x)/(\pi x)` for any argument
+:math:`x\ne 0`. ``sinc(0)`` takes the limit value 1, making ``sinc`` not
+only everywhere continuous but also infinitely differentiable.
+
+For full documentation refer to :obj:`numpy.sinc`.
+
+Parameters
+----------
+x : {dpnp.ndarray, usm_ndarray}
+    Input array, expected to have floating-point type.
+out : {None, dpnp.ndarray, usm_ndarray}, optional
+    Output array to populate.
+    Array must have the correct shape and the expected data type.
+    Default: ``None``.
+order : {"C", "F", "A", "K"}, optional
+    Memory layout of the newly output array, if parameter `out` is ``None``.
+    Default: ``"K"``.
+
+Returns
+-------
+out : dpnp.ndarray
+    An array containing the element-wise result of the ``sinc(x)`` function.
+    The data type of the returned array is determined by the Type Promotion
+    Rules.
+
+Limitations
+-----------
+Parameters `where` and `subok` are supported with their default values.
+Keyword argument `kwargs` is currently unsupported.
+Otherwise ``NotImplementedError`` exception will be raised.
+
+Notes
+-----
+The name sinc is short for "sine cardinal" or "sinus cardinalis".
+
+The sinc function is used in various signal processing applications, including
+in anti-aliasing, in the construction of a Lanczos resampling filter, and in
+interpolation.
+
+For bandlimited interpolation of discrete-time signals, the ideal interpolation
+kernel is proportional to the sinc function.
+
+Examples
+--------
+>>> import dpnp as np
+>>> x = np.linspace(-4, 4, 41, dtype=dpnp.float64)
+>>> np.sinc(x) # result may vary
+    array([ 0.        , -0.04923628, -0.08409186, -0.08903844, -0.05846808,
+            0.        ,  0.06682066,  0.11643488,  0.12613779,  0.08504448,
+            0.        , -0.10394325, -0.18920668, -0.21623621, -0.15591488,
+            0.        ,  0.23387232,  0.50455115,  0.75682673,  0.93548928,
+            1.        ,  0.93548928,  0.75682673,  0.50455115,  0.23387232,
+            0.        , -0.15591488, -0.21623621, -0.18920668, -0.10394325,
+            0.        ,  0.08504448,  0.12613779,  0.11643488,  0.06682066,
+            0.        , -0.05846808, -0.08903844, -0.08409186, -0.04923628,
+            0.        ])
+"""
+
+sinc = DPNPUnaryFunc(
+    "sinc",
+    ufi._sinc_result_type,
+    ufi._sinc,
+    _SINC_DOCSTRING,
+)
+
+
 _SUBTRACT_DOCSTRING = """
 Calculates the difference between each element `x1_i` of the input
 array `x1` and the respective element `x2_i` of the input array `x2`.