arb_hypgeom_dilog wrapper

flintlib · Aug 1, 2018 · 1968e54 · 1968e54
1 parent d30df8c
commit 1968e54
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diff --git a/arb_hypgeom.h b/arb_hypgeom.h
@@ -120,6 +120,8 @@ void arb_hypgeom_legendre_p_ui_root(arb_t res, arb_t weight, ulong n, ulong k, s
 
 void arb_hypgeom_central_bin_ui(arb_t res, ulong n, slong prec);
 
+void arb_hypgeom_dilog(arb_t res, const arb_t z, slong prec);
+
 #ifdef __cplusplus
 }
 #endif

diff --git a/arb_hypgeom/test/t-wrappers.c b/arb_hypgeom/test/t-wrappers.c
@@ -254,6 +254,10 @@ int main()
         arb_set_str(v, "[-0.3763617490859 +/- 3.83e-14]", prec);
         TEST(r, v, "legendre_q");
 
+        arb_hypgeom_dilog(r, a, prec);
+        arb_set_str(v, "[0.582240526465012 +/- 6.18e-16]", prec);
+        TEST(r, v, "dilog");
+
         arb_clear(a);
         arb_clear(b);
         arb_clear(c);

diff --git a/arb_hypgeom/wrappers.c b/arb_hypgeom/wrappers.c
@@ -629,3 +629,16 @@ arb_hypgeom_legendre_q(arb_t res, const arb_t n, const arb_t m, const arb_t z, i
     acb_clear(v);
 }
 
+void
+arb_hypgeom_dilog(arb_t res, const arb_t z, slong prec)
+{
+    acb_t t;
+    acb_init(t);
+    arb_set(acb_realref(t), z);
+    acb_hypgeom_dilog(t, t, prec);
+    if (acb_is_finite(t) && acb_is_real(t))
+        arb_swap(res, acb_realref(t));
+    else
+        arb_indeterminate(res);
+    acb_clear(t);
+}
diff --git a/doc/source/arb_hypgeom.rst b/doc/source/arb_hypgeom.rst
@@ -420,6 +420,13 @@ Orthogonal polynomials and functions
     subsequently refined using interval Newton steps with doubling working
     precision.
 
+Dilogarithm
+-------------------------------------------------------------------------------
+
+.. function:: void arb_hypgeom_dilog(arb_t res, const arb_t z slong prec)
+
+    Computes the dilogarithm `\operatorname{Li}_2(z)`.
+
 Hypergeometric sequences
 -------------------------------------------------------------------------------