Changes per review by @oleksandr-pavlyk

Author: ndgrigorian

dpctl/tensor/libtensor/include/kernels/elementwise_functions/expm1.hpp

@@ -70,18 +70,16 @@ template <typename argT, typename resT> struct Expm1Functor
             using realT = typename argT::value_type;
             // expm1(x + I*y) = expm1(x)*cos(y) - 2*sin(y / 2)^2 +
             // I*exp(x)*sin(y)
-            auto x = std::real(in);
-            const realT expm1X_val = std::expm1(x);
-            const realT expX_val = std::exp(x);
+            const realT x = std::real(in);
+            const realT y = std::imag(in);
 
-            x = std::imag(in);
             realT cosY_val;
-            const realT sinY_val = sycl::sincos(x, &cosY_val);
-            const realT sinhalfY_val = std::sin(x / realT{2});
+            const realT sinY_val = sycl::sincos(y, &cosY_val);
+            const realT sinhalfY_val = std::sin(y / 2);
 
             const realT res_re =
-                expm1X_val * cosY_val - realT{2} * sinhalfY_val * sinhalfY_val;
-            const realT res_im = expX_val * sinY_val;
+                std::expm1(x) * cosY_val - 2 * sinhalfY_val * sinhalfY_val;
+            const realT res_im = std::exp(x) * sinY_val;
             return resT{res_re, res_im};
         }
         else {

dpctl/tensor/libtensor/include/kernels/elementwise_functions/log1p.hpp

@@ -80,17 +80,17 @@ template <typename argT, typename resT> struct Log1pFunctor
             const realT y = std::imag(in);
 
             // imaginary part of result
-            const realT imagRes = std::atan2(y, x + 1);
+            const realT res_im = std::atan2(y, x + 1);
 
-            if (std::abs(in) < realT(.5)) {
-                const realT realRes = x * (2 + x) + y * y;
-                return {std::log1p(realRes) / 2, imagRes};
+            if (std::max(std::abs(x), std::abs(y)) < realT(.1)) {
+                const realT v = x * (2 + x) + y * y;
+                return {std::log1p(v) / 2, res_im};
             }
             else {
                 // when not close to zero,
                 // prevent overflow
-                const realT realRes = std::hypot(x + 1, y);
-                return {std::log(realRes), imagRes};
+                const realT m = std::hypot(x + 1, y);
+                return {std::log(m), res_im};
             }
         }
         else {