From 33dafb4ff579d468a5721cb1e540791b25e9e007 Mon Sep 17 00:00:00 2001
From: Pascal <molin.maths@gmail.com>
Date: Thu, 5 Oct 2017 13:37:35 +0200
Subject: [PATCH] add acb_dft function

---
 acb_dft.h           |  3 +++
 acb_dft/bluestein.c |  5 ++++-
 acb_dft/precomp.c   | 14 +++++++++++---
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/acb_dft.h b/acb_dft.h
index b638206f..189fb069 100644
--- a/acb_dft.h
+++ b/acb_dft.h
@@ -194,6 +194,8 @@ void _acb_dft_precomp_init(acb_dft_pre_t pre, slong dv, acb_ptr z, slong dz, slo
 void acb_dft_precomp_init(acb_dft_pre_t pre, slong len, slong prec);
 void acb_dft_precomp_clear(acb_dft_pre_t pre);
 
+void acb_dft(acb_ptr w, acb_srcptr v, slong len, slong prec);
+
 acb_dft_step_ptr _acb_dft_steps_prod(slong * m, slong num, slong prec);
 
 ACB_DFT_INLINE void
@@ -299,6 +301,7 @@ _acb_vec_kronecker_mul(acb_ptr z, acb_srcptr x, acb_srcptr y, slong len, slong p
         acb_mul(z + k, x + k, y + k, prec);
 }
 
+/* FIXME: no longer used */
 /* z[k] = conj(x[k])*y[k] */
 ACB_DFT_INLINE void
 acb_vec_kronecker_mul_conj(acb_ptr z, acb_srcptr x, acb_srcptr y, slong len, slong prec)
diff --git a/acb_dft/bluestein.c b/acb_dft/bluestein.c
index a720f5e7..1482086f 100644
--- a/acb_dft/bluestein.c
+++ b/acb_dft/bluestein.c
@@ -18,9 +18,13 @@ acb_dft_bluestein_init(acb_dft_bluestein_t t, slong n, slong prec)
     slong k, k2;
     acb_ptr z2n;
     int e = n_clog(2 * n - 1, 2);
+#if DFT_VERB
+    flint_printf("\n init bluestein e = %i", e);
+#endif
     acb_dft_rad2_init(t->rad2, e, prec);
 
     /* compute z[k] = e(-k^2/2n) */
+    /* TODO: check if this can be improved */
     z2n = _acb_vec_init(2 * n);
     _acb_vec_unit_roots(z2n, 2 * n, prec);
     nmod_init(&n2, 2 * n);
@@ -74,4 +78,3 @@ acb_dft_bluestein(acb_ptr w, acb_srcptr v, slong len, slong prec)
     acb_dft_bluestein_precomp(w, v, t, prec);
     acb_dft_bluestein_clear(t);
 }
-
diff --git a/acb_dft/precomp.c b/acb_dft/precomp.c
index bd84e9c6..f3900605 100644
--- a/acb_dft/precomp.c
+++ b/acb_dft/precomp.c
@@ -21,8 +21,7 @@ _acb_dft_precomp_init(acb_dft_pre_t pre, slong dv, acb_ptr z, slong dz, slong le
     }
     if (n_is_prime(len))
     {
-        /* TODO: need convolution if len is large */
-        if (len < 20)
+        if (len < 100)
         {
             pre->type = DFT_NAIVE;
             _acb_dft_naive_init(pre->t.naive, dv, z, dz, len, prec);
@@ -31,7 +30,7 @@ _acb_dft_precomp_init(acb_dft_pre_t pre, slong dv, acb_ptr z, slong dz, slong le
         {
             pre->type = DFT_CONV;
             /* FIXME: do not recompute the same bluestein
-             * scheme over and over */
+             * scheme if needed several times */
             acb_dft_bluestein_init(pre->t.bluestein, len, prec);
         }
     }
@@ -115,3 +114,12 @@ acb_dft_precomp(acb_ptr w, acb_srcptr v, const acb_dft_pre_t pre, slong prec)
             break;
     }
 }
+
+void
+acb_dft(acb_ptr w, acb_srcptr v, slong len, slong prec)
+{
+    acb_dft_pre_t t;
+    acb_dft_precomp_init(t, len, prec);
+    acb_dft_precomp(w, v, t, prec);
+    acb_dft_precomp_clear(t);
+}