expm1 special case change

ndgrigorian · ndgrigorian · commit 27ea9c26513c · 2023-08-10T14:12:18.000-07:00
For `inf` real part and finite, nonzero imaginary part, now guaranteed to be (+/-`inf`, +/-`inf`), with cosine and sine of the imaginary part determining the sign, respectively
diff --git a/dpctl/tensor/libtensor/include/kernels/elementwise_functions/expm1.hpp b/dpctl/tensor/libtensor/include/kernels/elementwise_functions/expm1.hpp
@@ -85,7 +85,8 @@ template <typename argT, typename resT> struct Expm1Functor
                         return in;
                     }
                     else {
-                        return (x * resT{std::cos(y), std::sin(y)});
+                        return (resT{std::copysign(x, std::cos(y)),
+                                     std::copysign(x, std::sin(y))});
                     }
                 }
                 else {

Original file line number	Diff line number	Diff line change
`@@ -85,7 +85,8 @@ template <typename argT, typename resT> struct Expm1Functor`
`85`	`85`	`return in;`
`86`	`86`	`}`
`87`	`87`	`else {`
`88`		`- return (x * resT{std::cos(y), std::sin(y)});`
	`88`	`+ return (resT{std::copysign(x, std::cos(y)),`
	`89`	`+ std::copysign(x, std::sin(y))});`
`89`	`90`	`}`
`90`	`91`	`}`
`91`	`92`	`else {`