New API to check for half support on given device

Also fixes a doc test in Array struct implementation

Author: 9prady9

src/core/array.rs

@@ -189,16 +189,20 @@ where
     /// An example of creating an Array from half::f16 array
     ///
     /// ```rust
-    /// use arrayfire::{Array, Dim4, print};
+    /// use arrayfire::{Array, Dim4, is_half_available, print};
     /// use half::f16;
     ///
     /// let values: [f32; 3] = [1.0, 2.0, 3.0];
     ///
-    /// let half_values = values.iter().map(|&x| f16::from_f32(x)).collect::<Vec<_>>();
+    /// if is_half_available(0) { // Default device is 0, hence the argument
+    ///     let half_values = values.iter().map(|&x| f16::from_f32(x)).collect::<Vec<_>>();
     ///
-    /// let hvals = Array::new(&half_values, Dim4::new(&[3, 1, 1, 1]));
+    ///     let hvals = Array::new(&half_values, Dim4::new(&[3, 1, 1, 1]));
     ///
-    /// print(&hvals);
+    ///     print(&hvals);
+    /// } else {
+    ///     println!("Half support isn't available on this device");
+    /// }
     /// ```
     ///
     pub fn new(slice: &[T], dims: Dim4) -> Self {

src/core/device.rs

@@ -36,6 +36,7 @@ extern "C" {
 
     fn af_alloc_pinned(non_pagable_ptr: *mut void_ptr, bytes: dim_t) -> c_int;
     fn af_free_pinned(non_pagable_ptr: void_ptr) -> c_int;
+    fn af_get_half_support(available: *mut c_int, device: c_int) -> c_int;
 }
 
 /// Get ArrayFire Version Number
@@ -331,3 +332,21 @@ pub unsafe fn free_pinned(ptr: void_ptr) {
     let err_val = af_free_pinned(ptr);
     HANDLE_ERROR(AfError::from(err_val));
 }
+
+/// Check if a device has half support
+///
+/// # Parameters
+///
+/// - `device` is the device for which half precision support is checked for
+///
+/// # Return Values
+///
+/// `True` if `device` device has half support, `False` otherwise.
+pub fn is_half_available(device: i32) -> bool {
+    unsafe {
+        let mut temp: i32 = 0;
+        let err_val = af_get_half_support(&mut temp as *mut c_int, device as c_int);
+        HANDLE_ERROR(AfError::from(err_val));
+        temp > 0
+    }
+}