Investigate small-arg logic as in issue

ckormanyos · ckormanyos · commit f52df1cb9ee8 · 2025-08-07T11:03:31.000+02:00
diff --git a/include/boost/math/special_functions/detail/bessel_jn.hpp b/include/boost/math/special_functions/detail/bessel_jn.hpp
@@ -84,7 +84,7 @@ BOOST_MATH_GPU_ENABLED T bessel_jn(int n, T x, const Policy& pol)
             current = value;
         }
     }
-    else if((x < 1) || (n > x * x / 4) || (x < 5))
+    else if((x < 1) || ((n > x * x / 4) && (x < 5)))
     {
        return factor * bessel_j_small_z_series(T(n), x, pol);
     }
diff --git a/include/boost/math/special_functions/detail/bessel_jy.hpp b/include/boost/math/special_functions/detail/bessel_jy.hpp
@@ -327,7 +327,7 @@ namespace boost { namespace math {
          // x is positive until reflection
          W = T(2) / (x * pi<T>());               // Wronskian
          T Yv_scale = 1;
-         if(((kind & need_y) == 0) && ((x < 1) || (v > x * x / 4) || (x < 5)))
+         if(((kind & need_y) == 0) && ((x < 1) || ((v > x * x / 4) && (x < 5))))
          {
             //
             // This series will actually converge rapidly for all small

Original file line number	Diff line number	Diff line change
`@@ -84,7 +84,7 @@ BOOST_MATH_GPU_ENABLED T bessel_jn(int n, T x, const Policy& pol)`
`84`	`84`	`current = value;`
`85`	`85`	`}`
`86`	`86`	`}`
`87`		`- else if((x < 1) \|\| (n > x * x / 4) \|\| (x < 5))`
	`87`	`+ else if((x < 1) \|\| ((n > x * x / 4) && (x < 5)))`
`88`	`88`	`{`
`89`	`89`	`return factor * bessel_j_small_z_series(T(n), x, pol);`
`90`	`90`	`}`
Original file line number	Diff line number	Diff line change
`@@ -327,7 +327,7 @@ namespace boost { namespace math {`
`327`	`327`	`// x is positive until reflection`
`328`	`328`	`W = T(2) / (x * pi<T>()); // Wronskian`
`329`	`329`	`T Yv_scale = 1;`
`330`		`- if(((kind & need_y) == 0) && ((x < 1) \|\| (v > x * x / 4) \|\| (x < 5)))`
	`330`	`+ if(((kind & need_y) == 0) && ((x < 1) \|\| ((v > x * x / 4) && (x < 5))))`
`331`	`331`	`{`
`332`	`332`	`//`
`333`	`333`	`// This series will actually converge rapidly for all small`