Merge pull request #45 from ederc/variable-permutation

Variable permutation

Author: ederc

Project.toml

@@ -1,7 +1,7 @@
 name = "AlgebraicSolving"
 uuid = "66b61cbe-0446-4d5d-9090-1ff510639f9d"
 authors = ["ederc <[email protected]>", "Mohab Safey El Din <[email protected]", "Rafael Mohr <[email protected]>"]
-version = "0.4.11"
+version = "0.4.12"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
@@ -26,4 +26,4 @@ Markdown = "1.6"
 Printf = "1.6"
 Random = "1.6"
 Test = "1.6"
-msolve_jll = "0.6.3"
+msolve_jll = "0.6.5"

src/algorithms/solvers.jl

@@ -141,8 +141,9 @@ function _core_msolve(
     jl_cf_lf = reinterpret(Ptr{BigInt}, res_cf_lf[])
 
     jl_vnames = Base.unsafe_wrap(Array, res_vnames[], jl_rp_nr_vars)
-
-    vsymbols = [Symbol(unsafe_string(jl_vnames[i])) for i in 1:jl_rp_nr_vars]
+    vsymbols  = [Symbol(unsafe_string(jl_vnames[i])) for i in 1:jl_rp_nr_vars]
+    #= get possible variable permutation =#
+    perm      = sortperm(vsymbols)
 
     rat_param = _get_rational_parametrization(jl_ld, jl_len,
                                               jl_cf, jl_cf_lf, jl_rp_nr_vars)
@@ -173,9 +174,9 @@ function _core_msolve(
         j = 1
         tmp = Vector{QQFieldElem}(undef, nr_vars)
         while j <= nr_vars
-            tmp[j]  = QQFieldElem(unsafe_load(jl_sols_num, i)) >> Int64(unsafe_load(jl_sols_den, i))
-            tmp[j] += QQFieldElem(unsafe_load(jl_sols_num, i+1)) >> Int64(unsafe_load(jl_sols_den, i+1))
-            tmp[j] = tmp[j] >> 1
+            tmp[perm[j]]  = QQFieldElem(unsafe_load(jl_sols_num, i)) >> Int64(unsafe_load(jl_sols_den, i))
+            tmp[perm[j]] += QQFieldElem(unsafe_load(jl_sols_num, i+1)) >> Int64(unsafe_load(jl_sols_den, i+1))
+            tmp[perm[j]] = tmp[perm[j]] >> 1
             i += 2
             j += 1
         end

test/algorithms/solvers.jl

@@ -17,7 +17,7 @@
     @test sols == real_solutions(I)
     @test rat_sols == rational_solutions(I)
     @test I.real_sols == real_solutions(I)
-    
+
     C, x = polynomial_ring(QQ, "x")
     elim  = 128304*x^8 - 93312*x^7 + 15552*x^6 + 3144*x^5 - 1120*x^4 + 36*x^3 + 15*x^2 - x
     denom = 1026432*x^7 - 653184*x^6 + 93312*x^5 + 15720*x^4 - 4480*x^3 + 108*x^2 + 30*x - 1
@@ -50,4 +50,13 @@
     I = Ideal([x1^2-x2, x1*x3, x2-12])
 	@test_throws ErrorException real_solutions(I)
 	@test_throws ErrorException rational_solutions(I)
+
+    # check variable permutation
+    R, (x, y) = polynomial_ring(QQ,["x","y"])
+    I = Ideal([x^2-1, y])
+    sols = Vector{QQFieldElem}[
+        [-1, 0],
+        [1, 0]
+            ]
+    @test sols == real_solutions(I)
 end