From 8f9f343127a50a8fcf0017793b8d78edae8c375e Mon Sep 17 00:00:00 2001
From: Fredrik Johansson <fredrik.johansson@gmail.com>
Date: Tue, 14 Feb 2017 14:31:48 +0100
Subject: [PATCH] add arb_is_int_2exp_si and acb_is_int_2exp_si

---
 acb.h                | 6 ++++++
 acb/polygamma.c      | 2 +-
 acb_elliptic/e_inc.c | 3 +--
 acb_elliptic/f.c     | 3 +--
 acb_elliptic/pi.c    | 4 +---
 arb.h                | 7 +++++++
 doc/source/acb.rst   | 4 ++++
 doc/source/arb.rst   | 4 ++++
 8 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/acb.h b/acb.h
index 42136fe9..735dd6eb 100644
--- a/acb.h
+++ b/acb.h
@@ -110,6 +110,12 @@ acb_is_int(const acb_t z)
     return arb_is_zero(acb_imagref(z)) && arb_is_int(acb_realref(z));
 }
 
+ACB_INLINE int
+acb_is_int_2exp_si(const acb_t z, slong e)
+{
+    return arb_is_zero(acb_imagref(z)) && arb_is_int_2exp_si(acb_realref(z), e);
+}
+
 ACB_INLINE void
 acb_zero(acb_t z)
 {
diff --git a/acb/polygamma.c b/acb/polygamma.c
index af601c40..161653de 100644
--- a/acb/polygamma.c
+++ b/acb/polygamma.c
@@ -30,7 +30,7 @@ acb_polygamma(acb_t res, const acb_t s, const acb_t z, slong prec)
         acb_gamma(u, t, prec);
         acb_hurwitz_zeta(t, t, z, prec);
 
-        if (arf_is_int_2exp_si(arb_midref(acb_realref(s)), 1))
+        if (acb_is_int_2exp_si(s, 1))
             acb_neg(t, t);
 
         acb_mul(res, t, u, prec);
diff --git a/acb_elliptic/e_inc.c b/acb_elliptic/e_inc.c
index ffb87b89..d01deda1 100644
--- a/acb_elliptic/e_inc.c
+++ b/acb_elliptic/e_inc.c
@@ -92,8 +92,7 @@ acb_elliptic_e_inc(acb_t res, const acb_t phi, const acb_t m, int times_pi, slon
         return;
     }
 
-    if (times_pi && acb_is_real(phi) && arb_is_exact(acb_realref(phi)) && 
-        arf_is_int_2exp_si(arb_midref(acb_realref(phi)), -1))
+    if (times_pi && acb_is_int_2exp_si(phi, -1))
     {
         acb_t t;
         acb_init(t);
diff --git a/acb_elliptic/f.c b/acb_elliptic/f.c
index 4b591b97..34afd8d7 100644
--- a/acb_elliptic/f.c
+++ b/acb_elliptic/f.c
@@ -77,8 +77,7 @@ acb_elliptic_f(acb_t res, const acb_t phi, const acb_t m, int times_pi, slong pr
         return;
     }
 
-    if (times_pi && acb_is_real(phi) && arb_is_exact(acb_realref(phi)) && 
-        arf_is_int_2exp_si(arb_midref(acb_realref(phi)), -1))
+    if (times_pi && acb_is_int_2exp_si(phi, -1))
     {
         acb_t t;
         acb_init(t);
diff --git a/acb_elliptic/pi.c b/acb_elliptic/pi.c
index e73b31d7..96144e77 100644
--- a/acb_elliptic/pi.c
+++ b/acb_elliptic/pi.c
@@ -113,9 +113,7 @@ acb_elliptic_pi_inc(acb_t res, const acb_t n, const acb_t phi, const acb_t m, in
         return;
     }
 
-    if (acb_is_zero(phi) || (times_pi && acb_is_real(phi)
-        && arb_is_exact(acb_realref(phi)) && 
-        arf_is_int_2exp_si(arb_midref(acb_realref(phi)), -1)))
+    if (acb_is_zero(phi) || (times_pi && acb_is_int_2exp_si(phi, -1)))
     {
         acb_t t;
         acb_init(t);
diff --git a/arb.h b/arb.h
index bcccf699..f0f9289c 100644
--- a/arb.h
+++ b/arb.h
@@ -290,6 +290,13 @@ arb_is_int(const arb_t x)
            arf_is_int(arb_midref(x));
 }
 
+ARB_INLINE int
+arb_is_int_2exp_si(const arb_t x, slong e)
+{
+    return mag_is_zero(arb_radref(x)) &&
+           arf_is_int_2exp_si(arb_midref(x), e);
+}
+
 ARB_INLINE int
 arb_contains_zero(const arb_t x)
 {
diff --git a/doc/source/acb.rst b/doc/source/acb.rst
index 923c7ebd..509210b8 100644
--- a/doc/source/acb.rst
+++ b/doc/source/acb.rst
@@ -225,6 +225,10 @@ Precision and comparisons
 
     Returns nonzero iff *z* is an exact integer.
 
+.. function:: int acb_is_int_2exp_si(const acb_t x, slong e)
+
+    Returns nonzero iff *z* exactly equals `n 2^e` for some integer *n*.
+
 .. function:: int acb_equal(const acb_t x, const acb_t y)
 
     Returns nonzero iff *x* and *y* are identical as sets, i.e.
diff --git a/doc/source/arb.rst b/doc/source/arb.rst
index 428f43bf..15c891ca 100644
--- a/doc/source/arb.rst
+++ b/doc/source/arb.rst
@@ -523,6 +523,10 @@ Comparisons
 
     Returns nonzero iff *x* is an exact integer.
 
+.. function:: int arb_is_int_2exp_si(const arb_t x, slong e)
+
+    Returns nonzero iff *x* exactly equals `n 2^e` for some integer *n*.
+
 .. function:: int arb_equal(const arb_t x, const arb_t y)
 
     Returns nonzero iff *x* and *y* are equal as balls, i.e. have both the