Merge pull request #2469 from andrjohns/feature/issue-2385-apply-unsigned

Fix apply_scalar_unary with unsigned and long arithmetic types

Author: rok-cesnovar

stan/math/prim/functor/apply_scalar_unary.hpp

@@ -3,6 +3,7 @@
 
 #include <stan/math/prim/fun/Eigen.hpp>
 #include <stan/math/prim/meta/is_eigen.hpp>
+#include <stan/math/prim/meta/require_generics.hpp>
 #include <stan/math/prim/meta/is_vector.hpp>
 #include <stan/math/prim/meta/is_vector_like.hpp>
 #include <stan/math/prim/meta/plain_type.hpp>
@@ -80,8 +81,8 @@ struct apply_scalar_unary<F, T, require_eigen_t<T>> {
  *
  * @tparam F Type of function defining static apply function.
  */
-template <typename F>
-struct apply_scalar_unary<F, double> {
+template <typename F, typename T>
+struct apply_scalar_unary<F, T, require_floating_point_t<T>> {
   /**
    * The return type, double.
    */
@@ -96,7 +97,7 @@ struct apply_scalar_unary<F, double> {
    * @param x Argument scalar.
    * @return Result of applying F to the scalar.
    */
-  static inline return_t apply(double x) { return F::fun(x); }
+  static inline return_t apply(T x) { return F::fun(x); }
 };
 
 /**
@@ -107,8 +108,8 @@ struct apply_scalar_unary<F, double> {
  *
  * @tparam F Type of function defining static apply function.
  */
-template <typename F>
-struct apply_scalar_unary<F, int> {
+template <typename F, typename T>
+struct apply_scalar_unary<F, T, require_integral_t<T>> {
   /**
    * The return type, double.
    */
@@ -123,7 +124,7 @@ struct apply_scalar_unary<F, int> {
    * @param x Argument scalar.
    * @return Result of applying F to the scalar.
    */
-  static inline return_t apply(int x) { return F::fun(static_cast<double>(x)); }
+  static inline return_t apply(T x) { return F::fun(static_cast<double>(x)); }
 };
 
 /**

test/unit/math/prim/fun/sqrt_test.cpp

@@ -6,4 +6,11 @@ TEST(MathFunctions, sqrtInt) {
   EXPECT_FLOAT_EQ(std::sqrt(3.0), sqrt(3));
   EXPECT_FLOAT_EQ(std::sqrt(3.1), sqrt(3.1));
   EXPECT_TRUE(stan::math::is_nan(sqrt(-2)));
+
+  uint32_t ulong = 1;
+  uint64_t ulonglong = 1;
+  long double ldouble = 1.5;
+  EXPECT_FLOAT_EQ(std::sqrt(ulong), sqrt(ulong));
+  EXPECT_FLOAT_EQ(std::sqrt(ulonglong), sqrt(ulonglong));
+  EXPECT_FLOAT_EQ(std::sqrt(ldouble), sqrt(ldouble));
 }