Refine gemv example

examples/pybind11/onemkl_gemv/solve.py

@@ -21,10 +21,6 @@
 import dpctl.tensor as dpt
 
 
-def empty_like(A):
-    return dpt.empty(A.shape, A.dtype, device=A.device)
-
-
 def chebyshev(A, b, x0, nIters, lMax, lMin, depends=[]):
     """Chebyshev iterative solver using SYCL routines"""
     d = (lMax + lMin) / 2
@@ -33,9 +29,9 @@ def chebyshev(A, b, x0, nIters, lMax, lMin, depends=[]):
     x = dpt.copy(x0)
     exec_queue = A.sycl_queue
     assert exec_queue == x.sycl_queue
-    Ax = empty_like(A[:, 0])
-    r = empty_like(Ax)
-    p = empty_like(Ax)
+    Ax = dpt.empty_like(A[:, 0])
+    r = dpt.empty_like(Ax)
+    p = dpt.empty_like(Ax)
 
     e_x = dpctl.SyclEvent()
     # Ax = A @ x
@@ -131,12 +127,13 @@ def cg_solve(A, b):
     converged is False if solver has not converged, or the iteration number
     """
     exec_queue = A.sycl_queue
-    x = dpt.zeros(b.shape, dtype=b.dtype)
-    Ap = empty_like(x)
+    x = dpt.zeros_like(b)
+    Ap = dpt.empty_like(x)
 
     all_host_tasks = []
-    r = dpt.copy(b)
-    p = dpt.copy(b)
+    r = dpt.copy(b)  # synchronous copy
+    p = dpt.copy(b)  # synchronous copy
+
     rsold = sycl_gemm.norm_squared_blocking(exec_queue, r)
     if rsold < 1e-20:
         return (b, 0)
@@ -147,22 +144,21 @@ def cg_solve(A, b):
     e_x = dpctl.SyclEvent()
     for i in range(max_iters):
         # Ap = A @ p
-        he_dot, e_dot = sycl_gemm.gemv(exec_queue, A, p, Ap, depends=[e_p])
-        all_host_tasks.append(he_dot)
+        he_gemv, e_gemv = sycl_gemm.gemv(exec_queue, A, p, Ap, depends=[e_p])
+        all_host_tasks.append(he_gemv)
         # alpha = rsold / dot(p, Ap)
         alpha = rsold / sycl_gemm.dot_blocking(
-            exec_queue, p, Ap, depends=[e_dot]
+            exec_queue, p, Ap, depends=[e_p, e_gemv]
         )
         # x = x + alpha * p
         he1_x_update, e1_x_update = sycl_gemm.axpby_inplace(
-            exec_queue, alpha, p, 1, x, depends=[e_p, e_x]
+            exec_queue, alpha, p, 1, x, depends=[e_x]
         )
         all_host_tasks.append(he1_x_update)
-        e_x = e1_x_update
 
         # r = r - alpha * Ap
         he2_r_update, e2_r_update = sycl_gemm.axpby_inplace(
-            exec_queue, -alpha, Ap, 1, r, depends=[e_p]
+            exec_queue, -alpha, Ap, 1, r
         )
         all_host_tasks.append(he2_r_update)
 

examples/pybind11/onemkl_gemv/sycl_gemm/_onemkl.cpp

@@ -497,6 +497,7 @@ py::object py_dot_blocking(sycl::queue q,
             reinterpret_cast<const T *>(v2_typeless_ptr), 1, res_usm, depends);
         T res_v{};
         q.copy<T>(res_usm, &res_v, 1, {dot_ev}).wait_and_throw();
+        sycl::free(res_usm, q);
         res = py::float_(res_v);
     }
     else if (v1_typenum == UAR_FLOAT) {
@@ -507,6 +508,7 @@ py::object py_dot_blocking(sycl::queue q,
             reinterpret_cast<const T *>(v2_typeless_ptr), 1, res_usm, depends);
         T res_v(0);
         q.copy<T>(res_usm, &res_v, 1, {dot_ev}).wait_and_throw();
+        sycl::free(res_usm, q);
         res = py::float_(res_v);
     }
     else if (v1_typenum == UAR_CDOUBLE) {
@@ -517,6 +519,7 @@ py::object py_dot_blocking(sycl::queue q,
             reinterpret_cast<const T *>(v2_typeless_ptr), 1, res_usm, depends);
         T res_v{};
         q.copy<T>(res_usm, &res_v, 1, {dotc_ev}).wait_and_throw();
+        sycl::free(res_usm, q);
         res = py::cast(res_v);
     }
     else if (v1_typenum == UAR_CFLOAT) {
@@ -527,6 +530,7 @@ py::object py_dot_blocking(sycl::queue q,
             reinterpret_cast<const T *>(v2_typeless_ptr), 1, res_usm, depends);
         T res_v{};
         q.copy<T>(res_usm, &res_v, 1, {dotc_ev}).wait_and_throw();
+        sycl::free(res_usm, q);
         res = py::cast(res_v);
     }
     else {

examples/pybind11/onemkl_gemv/sycl_gemm/cg_solver.hpp

@@ -177,16 +177,16 @@ int cg_solve(sycl::queue exec_q,
     }
 
     int converged_at = max_iters;
-    sycl::event prev_dep = copy_to_p_ev;
+    sycl::event e_p = copy_to_p_ev;
     sycl::event e_x = fill_ev;
 
     for (std::int64_t i = 0; i < max_iters; ++i) {
         sycl::event gemv_ev = oneapi::mkl::blas::row_major::gemv(
             exec_q, oneapi::mkl::transpose::N, n, n, T(1), Amat, n, p, 1, T(0),
-            Ap, 1, {prev_dep});
+            Ap, 1, {e_p});
 
         sycl::event pAp_dot_ev = oneapi::mkl::blas::row_major::dot(
-            exec_q, n, p, 1, Ap, 1, pAp_dot_dev, {prev_dep, gemv_ev});
+            exec_q, n, p, 1, Ap, 1, pAp_dot_dev, {e_p, gemv_ev});
 
         T pAp_dot_host{};
         exec_q.copy<T>(pAp_dot_dev, &pAp_dot_host, 1, {pAp_dot_ev})
@@ -212,8 +212,7 @@ int cg_solve(sycl::queue exec_q,
         T beta = rs_new / rs_old;
 
         // p = r + beta * p
-        prev_dep =
-            detail::axpby_inplace(exec_q, n, T(1), r, beta, p, {r_update_ev});
+        e_p = detail::axpby_inplace(exec_q, n, T(1), r, beta, p, {r_update_ev});
         e_x = x_update_ev;
 
         rs_old = rs_new;

examples/pybind11/onemkl_gemv/sycl_timing_solver.py

@@ -55,6 +55,12 @@
 A = dpt.asarray(Anp, "d", device=api_dev)
 b = dpt.asarray(bnp, "d", device=api_dev)
 
+assert A.sycl_queue == b.sycl_queue
+
+# allocate buffers for computation of residual
+r = dpt.empty_like(b)
+delta = dpt.empty_like(b)
+
 timer = dpctl.SyclTimer(time_scale=1e3)
 
 iters = []
@@ -64,17 +70,22 @@
 
     print(i, "(host_dt, device_dt)=", timer.dt)
     iters.append(conv_in)
+    assert x.usm_type == A.usm_type
+    assert x.usm_type == b.usm_type
+    assert x.sycl_queue == A.sycl_queue
+    assert x.sycl_queue == b.sycl_queue
 
 print("Converged in: ", iters)
 
-r = dpt.empty_like(b)
 hev, ev = sycl_gemm.gemv(q, A, x, r)
-delta = dpt.empty_like(b)
 hev2, ev2 = sycl_gemm.sub(q, r, b, delta, [ev])
 rs = sycl_gemm.norm_squared_blocking(q, delta)
 dpctl.SyclEvent.wait_for([hev, hev2])
 print(f"Python solution residual norm squared: {rs}")
 
+assert q == api_dev.sycl_queue
+print("")
+
 x_cpp = dpt.empty_like(b)
 iters = []
 for i in range(6):