Fix bug in ql_setup for hard step, all = 1, k = 0; use less roots for…

… hard step, all = 0, k = 0
flintlib · Feb 11, 2025 · 40469ee · 40469ee
1 parent 5dbcc32
commit 40469ee
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Showing 4 changed files with 23 additions and 7 deletions.
diff --git a/src/acb_theta/ql_exact.c b/src/acb_theta/ql_exact.c
@@ -440,10 +440,13 @@ acb_theta_ql_perform_steps(acb_ptr th, acb_ptr th_init, acb_srcptr rts,
             }
             else
             {
-                /* theta(z + t, tau)^2 = sum of theta(0, 2tau) theta(2z + 2t, 2tau) */
-                acb_theta_ql_step_1(th_next + 3 * j * n + n, th_init,
-                    th_init + 3 * j * n + n,
-                    rts + j * (3 * n * nb_steps) + k * (3 * n) + n, d0, d, g, prec);
+                if (k > 0)
+                {
+                    /* theta(z + t, tau)^2 = sum of theta(0, 2tau) theta(2z + 2t, 2tau) */
+                    acb_theta_ql_step_1(th_next + 3 * j * n + n, th_init,
+                        th_init + 3 * j * n + n,
+                        rts + j * (3 * n * nb_steps) + k * (3 * n) + n, d0, d, g, prec);
+                }
                 /* theta(z + 2t, tau)^2 = sum of theta(0, 2tau) theta(2z + 4t, 2tau) */
                 acb_theta_ql_step_1(th_next + 3 * j * n + 2 * n, th_init,
                     th_init + 3 * j * n + 2 * n,

diff --git a/src/acb_theta/ql_setup.c b/src/acb_theta/ql_setup.c
@@ -228,7 +228,14 @@ acb_theta_ql_setup_hard(acb_ptr rts, acb_ptr rts_all, acb_ptr t,
                 /* We just need roots for z + 2t */
                 th = rts_all + j * n * n;
                 acb_theta_sum(th, &aux[1], 1, ctx_tau, d, 1, 1, 1, prec);
-                res = !_acb_vec_contains_zero(rts, n * n);
+                res = !_acb_vec_contains_zero(th, n * n);
+            }
+            else if (k == 0)
+            {
+                /* We just need roots for z + 2t */
+                th = rts + j * (3 * n * nb_steps) + 2 * n;
+                acb_theta_sum(th, &aux[1], 1, ctx_tau, d, 1, 0, 1, prec);
+                res = !_acb_vec_contains_zero(th, n);
             }
             else
             {

diff --git a/src/acb_theta/test/main.c b/src/acb_theta/test/main.c
@@ -98,7 +98,7 @@ test_struct tests[] =
     //TEST_FUNCTION(acb_theta_ql_jet_fd),
     TEST_FUNCTION(acb_theta_ql_local_bound),
     TEST_FUNCTION(acb_theta_ql_lower_dim),
-    //TEST_FUNCTION(acb_theta_ql_setup),
+    TEST_FUNCTION(acb_theta_ql_setup),
     TEST_FUNCTION(acb_theta_siegel_cocycle),
     TEST_FUNCTION(acb_theta_siegel_is_reduced),
     TEST_FUNCTION(acb_theta_siegel_kappa),

diff --git a/src/acb_theta/test/t-ql_setup.c b/src/acb_theta/test/t-ql_setup.c
@@ -56,6 +56,11 @@ TEST_FUNCTION_START(acb_theta_ql_setup, state)
         if (!res)
         {
             flint_printf("FAIL (ql_setup)\n");
+            flint_printf("prec = %wd, nb = %wd, nb_steps = %wd, all = %wd, tau, z, distances:\n",
+                prec, nb, nb_steps, all);
+            acb_mat_printd(tau, 5);
+            _acb_vec_printd(zs, nb * g, 5);
+            _arb_vec_printd(distances, nb * n, 5);
             flint_abort();
         }
 
@@ -108,7 +113,8 @@ TEST_FUNCTION_START(acb_theta_ql_setup, state)
                             flint_abort();
                         }
                         if (k >= easy_steps[j]
-                            && acb_contains_zero(&rts[j * (3 * n * nb_steps) + k * (3 * n) + n + a]))
+                            && acb_contains_zero(&rts[j * (3 * n * nb_steps) + k * (3 * n) + n + a])
+                            && k > 0)
                         {
                             flint_printf("FAIL (root 2)\n");
                             flint_printf("j = %wd, k = %wd, a = %wd\n", j, k, a);