From 7d9ead1e4dfb210eedfacf0cb9b4f0b043ab8079 Mon Sep 17 00:00:00 2001
From: Pascal <molin.maths@gmail.com>
Date: Thu, 4 Aug 2016 15:35:33 +0200
Subject: [PATCH] change loop order (last component first)

---
 acb_dirichlet/conrey_next.c           |  2 +-
 acb_dirichlet/conrey_next_primitive.c | 13 +++++++++----
 acb_dirichlet/dft.c                   |  2 +-
 acb_dirichlet/l_hurwitz.c             |  6 ++----
 acb_dirichlet/l_vec_hurwitz.c         |  6 ++----
 acb_dirichlet/profile/p-conrey.c      |  4 ++--
 acb_dirichlet/test/t-conrey.c         |  8 +++-----
 acb_dirichlet/test/t-gauss.c          |  2 +-
 acb_dirichlet/test/t-jacobi.c         |  6 +++---
 acb_dirichlet/test/t-l.c              |  6 ++----
 acb_dirichlet/test/t-thetanull.c      |  6 ++----
 acb_dirichlet/test/t-vec.c            |  6 ++----
 acb_dirichlet/ui_chi_vec_loop.c       |  4 ++--
 13 files changed, 32 insertions(+), 39 deletions(-)

diff --git a/acb_dirichlet/conrey_next.c b/acb_dirichlet/conrey_next.c
index c17db899..e715ed93 100644
--- a/acb_dirichlet/conrey_next.c
+++ b/acb_dirichlet/conrey_next.c
@@ -30,7 +30,7 @@ acb_dirichlet_conrey_next(acb_dirichlet_conrey_t x, const acb_dirichlet_group_t
 {
     /* update index */
     int k;
-    for (k=0; k < G->num; k++)
+    for (k = G->num - 1; k >= 0; k--)
     {
         x->n = nmod_mul(x->n, G->generators[k], G->mod);
         x->log[k] += 1;
diff --git a/acb_dirichlet/conrey_next_primitive.c b/acb_dirichlet/conrey_next_primitive.c
index 682b9b24..d8a98022 100644
--- a/acb_dirichlet/conrey_next_primitive.c
+++ b/acb_dirichlet/conrey_next_primitive.c
@@ -30,7 +30,8 @@ acb_dirichlet_conrey_next_primitive(acb_dirichlet_conrey_t x, const acb_dirichle
 {
     /* update index avoiding multiples of p except for first component
        if 8|q */
-    ulong k = 0;
+    slong k = 0;
+    /*
     if (G->neven == 2)
     {
         x->n = nmod_mul(x->n, G->generators[0], G->mod);
@@ -40,14 +41,18 @@ acb_dirichlet_conrey_next_primitive(acb_dirichlet_conrey_t x, const acb_dirichle
         x->log[0] = 0;
         k = 1;
     }
-    for (; k < G->num ; k++)
+    */
+    for (k = G->num - 1; k >= 0; k--)
     {
         x->n = nmod_mul(x->n, G->generators[k], G->mod);
         x->log[k]++;
         if (x->log[k] % G->P[k].p == 0)
         {
-            x->n = nmod_mul(x->n, G->generators[k], G->mod);
-            x->log[k]++;
+            if (k > 0 || G->neven != 2)
+            {
+                x->n = nmod_mul(x->n, G->generators[k], G->mod);
+                x->log[k]++;
+            }
         }
         if (x->log[k] < G->P[k].phi)
             break;
diff --git a/acb_dirichlet/dft.c b/acb_dirichlet/dft.c
index aeeb99bb..82ea331d 100644
--- a/acb_dirichlet/dft.c
+++ b/acb_dirichlet/dft.c
@@ -32,7 +32,7 @@ acb_dirichlet_dft_conrey(acb_ptr w, acb_srcptr v, const acb_dirichlet_group_t G,
     slong k, l, * cyc;
     cyc = flint_malloc(G->num * sizeof(slong));
     for (k = 0, l = G->num - 1; l >= 0; k++, l--)
-        cyc[k] = G->P[l].phi;
+        cyc[k] = G->P[k].phi;
 
     acb_dirichlet_dft_prod(w, v, cyc, G->num, prec);
     flint_free(cyc);
diff --git a/acb_dirichlet/l_hurwitz.c b/acb_dirichlet/l_hurwitz.c
index 2fd4cc44..125fa7b9 100644
--- a/acb_dirichlet/l_hurwitz.c
+++ b/acb_dirichlet/l_hurwitz.c
@@ -33,7 +33,7 @@ acb_dirichlet_l_hurwitz(acb_t res, const acb_t s,
     xz = _acb_vec_init(chi->order.n);
     _acb_vec_set_powers(xz, z, chi->order.n, prec);
 
-    while (1) {
+    do {
         chin = acb_dirichlet_ui_chi_conrey(G, chi, cn);
 
         acb_set_ui(a, cn->n);
@@ -42,9 +42,7 @@ acb_dirichlet_l_hurwitz(acb_t res, const acb_t s,
 
         acb_addmul(t, xz + chin, u, prec);
 
-        if (acb_dirichlet_conrey_next(cn, G) == G->num)
-          break;
-    }
+    } while (acb_dirichlet_conrey_next(cn, G) >= 0);
 
     acb_set_ui(u, G->q);
     acb_neg(a, s);
diff --git a/acb_dirichlet/l_vec_hurwitz.c b/acb_dirichlet/l_vec_hurwitz.c
index 297e1e0d..160577e8 100644
--- a/acb_dirichlet/l_vec_hurwitz.c
+++ b/acb_dirichlet/l_vec_hurwitz.c
@@ -43,17 +43,15 @@ acb_dirichlet_l_vec_hurwitz(acb_ptr res, const acb_t s,
 
     zeta = z = _acb_vec_init(G->phi_q);
     acb_dirichlet_conrey_one(cn, G);
-    while (1) {
+    do {
 
         acb_set_ui(a, cn->n);
         acb_div_ui(a, a, G->q, prec);
         acb_hurwitz_zeta(z, s, a, prec);
         acb_mul(z, z, qs, prec);
 
-        if (acb_dirichlet_conrey_next(cn, G) == G->num)
-          break;
         z++;
-    }
+    } while (acb_dirichlet_conrey_next(cn, G) >= 0);
 
     acb_dirichlet_dft_conrey(res, zeta, G, prec);
 
diff --git a/acb_dirichlet/profile/p-conrey.c b/acb_dirichlet/profile/p-conrey.c
index 4c52a062..899758b5 100644
--- a/acb_dirichlet/profile/p-conrey.c
+++ b/acb_dirichlet/profile/p-conrey.c
@@ -59,7 +59,7 @@ int main()
         acb_dirichlet_conrey_one(x, G);
         n++;
 
-        for (; acb_dirichlet_conrey_next(x, G) < G->num; n++);
+        for (; acb_dirichlet_conrey_next(x, G) >= 0; n++);
         acb_dirichlet_conrey_clear(x);
         acb_dirichlet_group_clear(G);
     }
@@ -83,7 +83,7 @@ int main()
         acb_dirichlet_char_one(chi, G);
         n++;
 
-        for (; acb_dirichlet_char_next(chi, G) < G->num; n++);
+        for (; acb_dirichlet_char_next(chi, G) >= 0; n++);
         acb_dirichlet_char_clear(chi);
         acb_dirichlet_group_clear(G);
     }
diff --git a/acb_dirichlet/test/t-conrey.c b/acb_dirichlet/test/t-conrey.c
index 7dadf2d7..bc93570d 100644
--- a/acb_dirichlet/test/t-conrey.c
+++ b/acb_dirichlet/test/t-conrey.c
@@ -54,7 +54,7 @@ int main()
         sum = 1;
 
 #if 1
-        for (n = 1; acb_dirichlet_conrey_next(x, G) < G->num; n++)
+        for (n = 1; acb_dirichlet_conrey_next(x, G) >= 0; n++)
             sum += x->n * x->n;
 #else
         /* iteration much faster than gcd below */
@@ -71,12 +71,10 @@ int main()
         /* use http://oeis.org/A053818 to check all elements
          * are gone through */
         ref = (q % 4 == 2) ? -2 : 1;
-        k = (G->neven == 2) ? 1 : 0;
-        for (; k<G->num; k++)
+        for (k = (G->neven == 2); k < G->num; k++)
             ref = - ref * G->P[k].p;
         ref = ( G->phi_q * (2 * q * q + ref) ) / 6;
 
-
         if (n != G->phi_q)
         {
             flint_printf("FAIL: group size\n\n");
@@ -98,7 +96,7 @@ int main()
             continue;
 
         acb_dirichlet_conrey_first_primitive(x, G);
-        for (n = 1; (k=acb_dirichlet_conrey_next_primitive(x, G)) < G->num; n++);
+        for (n = 1; acb_dirichlet_conrey_next_primitive(x, G) >= 0; n++);
 
         ref = acb_dirichlet_number_primitive(G);
         if (n != ref)
diff --git a/acb_dirichlet/test/t-gauss.c b/acb_dirichlet/test/t-gauss.c
index a44b345e..a72f72b2 100644
--- a/acb_dirichlet/test/t-gauss.c
+++ b/acb_dirichlet/test/t-gauss.c
@@ -81,7 +81,7 @@ int main()
                 abort();
             }
 
-            if (acb_dirichlet_conrey_next(x, G) == G->num)
+            if (acb_dirichlet_conrey_next(x, G) < 0)
                 break;
         }
         acb_clear(s1);
diff --git a/acb_dirichlet/test/t-jacobi.c b/acb_dirichlet/test/t-jacobi.c
index e1f18152..5f7dcaec 100644
--- a/acb_dirichlet/test/t-jacobi.c
+++ b/acb_dirichlet/test/t-jacobi.c
@@ -35,7 +35,7 @@ int main()
 
     /* check Jacobi sums */
 
-    for (q = 29*29; q > 1; q = q%2 ? 3*q+1 : q/2)
+    for (q = 29 * 29; q > 1; q = q%2 ? 3*q+1 : q/2)
     {
         slong m1, m2;
         acb_dirichlet_group_t G;
@@ -78,12 +78,12 @@ int main()
                             );
                     abort();
                 }
-                if (acb_dirichlet_char_next(chi2, G) == G->num)
+                if (acb_dirichlet_char_next(chi2, G) < 0)
                     break;
 
             }
 
-            if (acb_dirichlet_char_next(chi1, G) == G->num)
+            if (acb_dirichlet_char_next(chi1, G) < 0)
                 break;
 
         }
diff --git a/acb_dirichlet/test/t-l.c b/acb_dirichlet/test/t-l.c
index 6afade68..40468922 100644
--- a/acb_dirichlet/test/t-l.c
+++ b/acb_dirichlet/test/t-l.c
@@ -56,7 +56,7 @@ test_dft()
 
     i = 0;
     acb_dirichlet_conrey_one(x, G);
-    while (1) {
+    do {
 
         acb_dirichlet_char_conrey(chi, G, x);
         acb_dirichlet_l_hurwitz(z, s, G, chi, prec);
@@ -73,10 +73,8 @@ test_dft()
             flint_printf("\n\n");
         }
 
-        if (acb_dirichlet_conrey_next(x, G) == G->num)
-          break;
         i++;
-    }
+    } while (acb_dirichlet_conrey_next(x, G) >= 0);
 
     acb_clear(s);
     _acb_vec_clear(v, G->phi_q);
diff --git a/acb_dirichlet/test/t-thetanull.c b/acb_dirichlet/test/t-thetanull.c
index aa2dcae1..78226781 100644
--- a/acb_dirichlet/test/t-thetanull.c
+++ b/acb_dirichlet/test/t-thetanull.c
@@ -84,7 +84,7 @@ int main()
         acb_init(sum);
         acb_dirichlet_char_first_primitive(chi, G);
 
-        while (1) {
+        do {
             ulong m;
             acb_zero(sum);
 
@@ -119,10 +119,8 @@ int main()
                 flint_printf("\n");
                 abort();
             }
+        } while (acb_dirichlet_char_next_primitive(chi, G) >= 0);
 
-            if (acb_dirichlet_char_next_primitive(chi, G) == G->num)
-                break;
-        }
         _acb_vec_clear(z, G->expo);
         _arb_vec_clear(t, nv);
         acb_clear(zeta);
diff --git a/acb_dirichlet/test/t-vec.c b/acb_dirichlet/test/t-vec.c
index 79cc2cdf..9c094c2b 100644
--- a/acb_dirichlet/test/t-vec.c
+++ b/acb_dirichlet/test/t-vec.c
@@ -59,7 +59,7 @@ int main()
 
         acb_dirichlet_conrey_one(x, G);
 
-        while (1) {
+        do {
 
             acb_dirichlet_char_conrey(chi, G, x);
 
@@ -73,9 +73,7 @@ int main()
                 abort();
             }
 
-            if (acb_dirichlet_conrey_next(x, G) == G->num)
-                break;
-        }
+        } while (acb_dirichlet_conrey_next(x, G) >= 0);
 
         flint_free(v1);
         flint_free(v2);
diff --git a/acb_dirichlet/ui_chi_vec_loop.c b/acb_dirichlet/ui_chi_vec_loop.c
index 6ad0179c..88eb88e1 100644
--- a/acb_dirichlet/ui_chi_vec_loop.c
+++ b/acb_dirichlet/ui_chi_vec_loop.c
@@ -41,10 +41,10 @@ acb_dirichlet_ui_chi_vec_loop(ulong *v, const acb_dirichlet_group_t G, const acb
 
     t = v[1] = 0;
 
-    while ( (j = acb_dirichlet_conrey_next(x, G)) < G->num )
+    while ( (j = acb_dirichlet_conrey_next(x, G)) >= 0 )
     {
         /* exponents were modified up to j */
-        for (k = 0; k <= j; k++)
+        for (k = G->num - 1; k >= j; k--)
             t = nmod_add(t, chi->expo[k], chi->order);
 
         if (x->n < nv)