Remove "using namespace mlx::core" in benchmarks/examples (#1685)

* Remove "using namespace mlx::core" in benchmarks/examples

* Fix building example extension

* A missing one in comment

* Fix building on M chips

examples/cpp/tutorial.cpp

@@ -5,11 +5,11 @@
 
 #include "mlx/mlx.h"
 
-using namespace mlx::core;
+namespace mx = mlx::core;
 
 void array_basics() {
   // Make a scalar array:
-  array x(1.0);
+  mx::array x(1.0);
 
   // Get the value out of it:
   auto s = x.item<float>();
@@ -29,31 +29,31 @@ void array_basics() {
 
   // The datatype should be float32:
   auto dtype = x.dtype();
-  assert(dtype == float32);
+  assert(dtype == mx::float32);
 
   // Specify the dtype when constructing the array:
-  x = array(1, int32);
-  assert(x.dtype() == int32);
+  x = mx::array(1, mx::int32);
+  assert(x.dtype() == mx::int32);
   x.item<int>(); // OK
   // x.item<float>();  // Undefined!
 
   // Make a multidimensional array:
-  x = array({1.0f, 2.0f, 3.0f, 4.0f}, {2, 2});
+  x = mx::array({1.0f, 2.0f, 3.0f, 4.0f}, {2, 2});
   // mlx is row-major by default so the first row of this array
   // is [1.0, 2.0] and the second row is [3.0, 4.0]
 
   // Make an array of shape {2, 2} filled with ones:
-  auto y = ones({2, 2});
+  auto y = mx::ones({2, 2});
 
   // Pointwise add x and y:
-  auto z = add(x, y);
+  auto z = mx::add(x, y);
 
   // Same thing:
   z = x + y;
 
   // mlx is lazy by default. At this point `z` only
   // has a shape and a type but no actual data:
-  assert(z.dtype() == float32);
+  assert(z.dtype() == mx::float32);
   assert(z.shape(0) == 2);
   assert(z.shape(1) == 2);
 
@@ -63,33 +63,33 @@ void array_basics() {
   // and inputs. When `eval` is called on an array (or arrays), the array and
   // all of its dependencies are recursively evaluated to produce the result.
   // Once an array is evaluated, it has data and is detached from its inputs.
-  eval(z);
+  mx::eval(z);
 
-  // Of course the array can still be an input to other operations. You can even
-  // call eval on the array again, this will just be a no-op:
-  eval(z); // no-op
+  // Of course the array can still be an input to other operations. You can
+  // even call eval on the array again, this will just be a no-op:
+  mx::eval(z); // no-op
 
   // Some functions or methods on arrays implicitly evaluate them. For example
   // accessing a value in an array or printing the array implicitly evaluate it:
-  z = ones({1});
+  z = mx::ones({1});
   z.item<float>(); // implicit evaluation
 
-  z = ones({2, 2});
+  z = mx::ones({2, 2});
   std::cout << z << std::endl; // implicit evaluation
 }
 
 void automatic_differentiation() {
-  auto fn = [](array x) { return square(x); };
+  auto fn = [](mx::array x) { return mx::square(x); };
 
   // Computing the derivative function of a function
-  auto grad_fn = grad(fn);
+  auto grad_fn = mx::grad(fn);
   // Call grad_fn on the input to get the derivative
-  auto x = array(1.5);
+  auto x = mx::array(1.5);
   auto dfdx = grad_fn(x);
   // dfdx is 2 * x
 
   // Get the second derivative by composing grad with grad
-  auto d2fdx2 = grad(grad(fn))(x);
+  auto d2fdx2 = mx::grad(mx::grad(fn))(x);
   // d2fdx2 is 2
 }