1 euro bet

src/f4/hashtable.jl

@@ -280,31 +280,30 @@ function hashtable_resize_if_needed!(ht::MonomialHashtable, added::Int)
     while hashtable_needs_resize(newsize, ht.load, added)
         newsize *= 2
     end
-    if newsize != ht.size
-        @invariant !ht.frozen
+    newsize == ht.size && return nothing
 
-        ht.size = newsize
-        @assert ispow2(ht.size)
+    @invariant !ht.frozen
+    ht.size = newsize
+    @invariant ispow2(ht.size)
 
-        resize!(ht.hashdata, ht.size)
-        resize!(ht.monoms, ht.size)
-        resize!(ht.hashtable, ht.size)
-        @inbounds for i in 1:(ht.size)
-            ht.hashtable[i] = zero(MonomId)
-        end
+    resize!(ht.hashdata, ht.size)
+    resize!(ht.monoms, ht.size)
+    resize!(ht.hashtable, ht.size)
+    @inbounds for i in 1:(ht.size)
+        ht.hashtable[i] = zero(MonomId)
+    end
 
-        mod = MonomHash(ht.size - 1)
-
-        @inbounds for i in (ht.offset):(ht.load)
-            # hash for this elem is already computed
-            he = ht.hashdata[i].hash
-            hidx = he
-            for j in MonomHash(1):MonomHash(ht.size)
-                hidx = hashtable_next_lookup_index(he, j, mod)
-                !iszero(ht.hashtable[hidx]) && continue
-                ht.hashtable[hidx] = i
-                break
-            end
+    mod = MonomHash(ht.size - 1)
+
+    @inbounds for i in (ht.offset):(ht.load)
+        # hash for this elem is already computed
+        he = ht.hashdata[i].hash
+        hidx = he
+        for j in MonomHash(1):MonomHash(ht.size)
+            hidx = hashtable_next_lookup_index(he, j, mod)
+            !iszero(ht.hashtable[hidx]) && continue
+            ht.hashtable[hidx] = i
+            break
         end
     end
     nothing

src/fglm/fglm_internal.jl

@@ -28,6 +28,8 @@ function enumerator_produce_next_monomials!(
     while m.load + ht.nvars >= length(m.monoms)
         resize!(m.monoms, length(m.monoms) * 2)
     end
+    # TODO: maybe an error, uncomment this line later
+    # hashtable_resize_if_needed!(ht, ht.nvars)
 
     emonom = ht.monoms[monom]
     @inbounds for i in 1:(ht.nvars)
@@ -80,6 +82,8 @@ function staircase_divides_monom(monom, staircase, ht)
     false
 end
 
+const _seen = Dict()
+
 function fglm_main!(
     ring::PolyRing,
     basis::Basis{C},
@@ -92,6 +96,7 @@ function fglm_main!(
         from ordering: $(ring.ord)
         to ordering:   $ord"""
 
+    empty!(_seen)
     monom_enumerator = enumerator_initialize(ht, ord)
     new_basis = basis_initialize(ring, basis.nfilled, C)
     matrix = wide_matrix_initialize(basis)
@@ -110,6 +115,10 @@ function fglm_main!(
             continue
         end
 
+        if haskey(_seen, monom)
+            throw("This monomial has been processed before !")
+        end
+        _seen[monom] = 1
         # Compute the normal form of the monomial w.r.t. by constructing and
         # echelonizing the F4 matrix.
         to_be_reduced = basis_initialize(ring, [[monom]], [C[1]])