use assignment and fix the test

Author: gojakuch

common/unified/solver/pipe_cg_kernels.cpp

@@ -125,7 +125,7 @@ void step_1(std::shared_ptr<const DefaultExecutor> exec,
                 x(row, col) += tmp * p(row, col);
                 r(row, col) -= tmp * q(row, col);
                 z1(row, col) -= tmp * f(row, col);
-                z2(row, col) -= tmp * f(row, col);
+                z2(row, col) = z1(row, col);
                 w(row, col) -= tmp * g(row, col);
             }
         },

test/solver/pipe_cg_kernels.cpp

@@ -47,7 +47,7 @@ class PipeCg : public CommonTestFixture {
         b = gen_mtx(size_m, size_n, size_n + 2);
         r = gen_mtx(size_m, size_n, size_n + 2);
         z1 = gen_mtx(size_m, size_n, size_n + 2);
-        z2 = gen_mtx(size_m, size_n, size_n + 2);
+        z2 = gko::clone(z1);
         w = gen_mtx(size_m, size_n, size_n + 2);
         m = gen_mtx(size_m, size_n, size_n + 2);
         n = gen_mtx(size_m, size_n, size_n + 2);