From 56c6b4de2eb5eb5a894a86c1602739158511a42d Mon Sep 17 00:00:00 2001
From: fredrik <fredrik.johansson@gmail.com>
Date: Thu, 25 Nov 2021 13:55:44 +0100
Subject: [PATCH] mag_pow_fmpz: allow negative exponents

---
 doc/source/mag.rst          |  4 ++--
 fmpr/pow_sloppy.c           |  1 +
 mag/pow_fmpz.c              | 14 ++++++++++++--
 mag/test/t-pow_fmpz.c       |  1 -
 mag/test/t-pow_fmpz_lower.c |  1 -
 5 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/doc/source/mag.rst b/doc/source/mag.rst
index 991b3357..48891427 100644
--- a/doc/source/mag.rst
+++ b/doc/source/mag.rst
@@ -378,13 +378,13 @@ Powers and logarithms
 
 .. function:: void mag_pow_fmpz(mag_t res, const mag_t x, const fmpz_t e)
 
-    Sets *res* to an upper bound for `x^e`. Requires `e \ge 0`.
+    Sets *res* to an upper bound for `x^e`.
 
 .. function:: void mag_pow_ui_lower(mag_t res, const mag_t x, ulong e)
 
 .. function:: void mag_pow_fmpz_lower(mag_t res, const mag_t x, const fmpz_t e)
 
-    Sets *res* to a lower bound for `x^e`. Requires `e \ge 0`.
+    Sets *res* to a lower bound for `x^e`.
 
 .. function:: void mag_sqrt(mag_t res, const mag_t x)
 
diff --git a/fmpr/pow_sloppy.c b/fmpr/pow_sloppy.c
index 59dc193f..8ed17cfd 100644
--- a/fmpr/pow_sloppy.c
+++ b/fmpr/pow_sloppy.c
@@ -35,6 +35,7 @@ fmpr_pow_sloppy_fmpz(fmpr_t y, const fmpr_t b, const fmpz_t e,
             ? FMPR_RND_UP : FMPR_RND_DOWN);
         fmpr_ui_div(y, UWORD(1), y, prec, rnd);
         fmpz_clear(f);
+        return;
     }
 
     if (y == b)
diff --git a/mag/pow_fmpz.c b/mag/pow_fmpz.c
index 6342e9f9..1a325f7f 100644
--- a/mag/pow_fmpz.c
+++ b/mag/pow_fmpz.c
@@ -16,7 +16,12 @@ mag_pow_fmpz(mag_t z, const mag_t x, const fmpz_t e)
 {
     if (fmpz_sgn(e) < 0)
     {
-        flint_abort();
+        fmpz_t t;
+        fmpz_init(t);
+        fmpz_neg(t, e);
+        mag_inv(z, x);
+        mag_pow_fmpz(z, z, t);
+        fmpz_clear(t);
     }
     else if (!COEFF_IS_MPZ(*e))
     {
@@ -50,7 +55,12 @@ mag_pow_fmpz_lower(mag_t z, const mag_t x, const fmpz_t e)
 {
     if (fmpz_sgn(e) < 0)
     {
-        flint_abort();
+        fmpz_t t;
+        fmpz_init(t);
+        fmpz_neg(t, e);
+        mag_inv_lower(z, x);
+        mag_pow_fmpz_lower(z, z, t);
+        fmpz_clear(t);
     }
     else if (!COEFF_IS_MPZ(*e))
     {
diff --git a/mag/test/t-pow_fmpz.c b/mag/test/t-pow_fmpz.c
index edc83da7..09c80d97 100644
--- a/mag/test/t-pow_fmpz.c
+++ b/mag/test/t-pow_fmpz.c
@@ -38,7 +38,6 @@ int main()
         mag_randtest_special(xb, state, 80);
         mag_randtest_special(yb, state, 80);
         fmpz_randtest(e, state, 200);
-        fmpz_abs(e, e);
 
         mag_get_fmpr(x, xb);
 
diff --git a/mag/test/t-pow_fmpz_lower.c b/mag/test/t-pow_fmpz_lower.c
index 905ee35d..7a077543 100644
--- a/mag/test/t-pow_fmpz_lower.c
+++ b/mag/test/t-pow_fmpz_lower.c
@@ -38,7 +38,6 @@ int main()
         mag_randtest_special(xb, state, 80);
         mag_randtest_special(yb, state, 80);
         fmpz_randtest(e, state, 200);
-        fmpz_abs(e, e);
 
         mag_get_fmpr(x, xb);