fixing mysterious power series bug

Author: pogudingleb

src/ODE.jl

@@ -241,7 +241,7 @@ end
 Input: ode is an ODE over QQ, p is a prime number
 Output: the reduction mod p, throws an exception if p divides one of the denominators
 """
-function reduce_ode_mod_p(ode::ODE, p::Int)
+function reduce_ode_mod_p(ode::ODE{<:MPolyRingElem{Nemo.QQFieldElem}}, p::Int)
     new_ring, new_vars =
         Nemo.polynomial_ring(Nemo.Native.GF(p), map(var_to_str, gens(ode.poly_ring)))
     new_type = typeof(new_vars[1])

src/parametrizations.jl

@@ -218,11 +218,7 @@ $sat_string
     $tagged_mqs
     Monom ordering:
     $(ord)"""
-    tagged_mqs_gb = groebner(
-        tagged_mqs,
-        ordering = ord,
-        homogenize = :no,
-    )
+    tagged_mqs_gb = groebner(tagged_mqs, ordering = ord, homogenize = :no)
     # Relations between tags in K[T]
     relations_between_tags = filter(
         poly -> isempty(intersect(vars(poly), vcat(sat_var, orig_vars))),

src/power_series_utils.jl

@@ -52,7 +52,7 @@ function ps_matrix_inv(
     power_series_ring = base_ring(parent(M))
     result = map(a -> power_series_ring(a), Base.inv(const_term))
     cur_prec = 1
-    while cur_prec <= prec
+    while cur_prec < prec
         result = _matrix_inv_newton_iteration(M, result)
         cur_prec *= 2
     end
@@ -161,7 +161,7 @@ function ps_matrix_homlinear_de(
         (one(parent(A)) + gen(ps_ring) * truncate_matrix(A, cur_prec)) *
         map(e -> truncate(ps_ring(e), cur_prec), Y0)
     Z = map(e -> truncate(ps_ring(e), cur_prec), Base.inv(Y0))
-    while cur_prec <= prec
+    while cur_prec < prec
         matrix_set_precision!(Y, 2 * cur_prec)
         matrix_set_precision!(Z, cur_prec)
         Y, Z = _matrix_homlinear_de_newton_iteration(A, Y, Z, cur_prec)
@@ -239,8 +239,7 @@ function ps_ode_solution(
     Svconst = AbstractAlgebra.matrix_space(base_ring(ring), n, 1)
     eqs = Sv(equations)
 
-    x_vars = filter(v -> ("$(v)_dot" in map(string, gens(ring))), gens(ring))
-    x_vars = [x for x in x_vars]
+    x_vars = collect(filter(v -> ("$(v)_dot" in map(var_to_str, gens(ring))), gens(ring)))
     x_dot_vars = [str_to_var(var_to_str(x) * "_dot", ring) for x in x_vars]
 
     Jac_dots = S([derivative(p, xd) for p in equations, xd in x_dot_vars])
@@ -260,14 +259,14 @@ function ps_ode_solution(
     end
 
     cur_prec = 1
-    while cur_prec <= prec
+    while cur_prec < prec
         @debug "\t Computing power series solution, currently at precision $cur_prec"
-        new_prec = min(prec + 1, 2 * cur_prec)
+        new_prec = min(prec, 2 * cur_prec)
         for i in 1:length(x_vars)
             set_precision!(solution[x_vars[i]], new_prec)
             set_precision!(solution[x_dot_vars[i]], new_prec)
         end
-        eval_point = [solution[v] for v in gens(ring)]
+        eval_point = [copy(solution[v]) for v in gens(ring)]
         map(ps -> set_precision!(ps, 2 * cur_prec), eval_point)
         eqs_eval = map(p -> evaluate(p, eval_point), eqs)
         J_eval = map(p -> evaluate(p, eval_point), Jac_xs)

src/wronskian.jl

@@ -237,7 +237,7 @@ Computes the Wronskians of io_equations
 
     @debug "Constructing Wronskians"
     result = []
-    for (i, tlist) in enumerate(termlists)
+    for tlist in termlists
         n = length(tlist)
         evaled = massive_eval(tlist, ps_ext)
         S = Nemo.matrix_space(F, n, n)