From f443719de1b64c324929a31691c479d1ca1bdacb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Tue, 25 Jul 2023 16:33:11 -0400
Subject: [PATCH] Fix in staircase dependence (#60)

* Fix in staircase dependence

* Fix format
---
 src/dependence.jl |  2 +-
 test/extract.jl   |  7 +------
 test/null.jl      | 34 +++++++++++++++++++++++++++++-----
 test/utils.jl     |  7 +++++++
 4 files changed, 38 insertions(+), 12 deletions(-)
 create mode 100644 test/utils.jl

diff --git a/src/dependence.jl b/src/dependence.jl
index 9dcda78..f5cfd6d 100644
--- a/src/dependence.jl
+++ b/src/dependence.jl
@@ -161,7 +161,7 @@ function StaircaseDependence(
             border = shift * mono
             if isnothing(_monomial_index(standard, border)) &&
                isnothing(_monomial_index(corners, border))
-                i = _index(basis, mono)
+                i = _index(basis, border)
                 if isnothing(i) || !is_dependent(i)
                     push!(independent_border, border)
                 else
diff --git a/test/extract.jl b/test/extract.jl
index d2f2e42..387021d 100644
--- a/test/extract.jl
+++ b/test/extract.jl
@@ -24,12 +24,7 @@ end
 
 Mod.@polyvar x
 
-function testelements(X, Y, atol)
-    @test length(X) == length(Y)
-    for y in Y
-        @test any(x -> isapprox(x, y, atol = atol), X)
-    end
-end
+include("utils.jl")
 
 function _atoms(atoms, rank_check, solver)
     Mod.@polyvar x[1:2]
diff --git a/test/null.jl b/test/null.jl
index 84aeca2..83f56f6 100644
--- a/test/null.jl
+++ b/test/null.jl
@@ -7,7 +7,31 @@ import MultivariateMoments as MM
 
 b(x) = MB.MonomialBasis(x)
 
-function test_univariate_infinity(x)
+include("utils.jl")
+
+function test_dreesen1(x, y)
+    matrix = Float64[
+        1 0 0 0
+        0 1 0 0
+        0 0 1 0
+        0 0 0 1
+        0 0 1 0
+        1 0 0 0
+    ]
+    basis = MB.MonomialBasis([1, y, x, y^2, x * y, x^2])
+    null = MM.MacaulayNullspace(matrix, basis, 1e-8)
+    @testset "$D" for D in [MM.AnyDependence, MM.StaircaseDependence]
+        @testset "$name" for (solver, name) in [
+            (MM.ShiftNullspace{D}(), "shift"),
+            #(MM.Echelon{D}(fallback = false), "echelon no fallback"),
+            #(MM.Echelon{D}(fallback = true), "echelon fallback"),
+        ]
+            @test isnothing(MM.solve(null, solver))
+        end
+    end
+end
+
+function _test_univariate_infinity(x, y)
     Z = Float64[
         1 0
         2 0
@@ -51,12 +75,12 @@ using Test
 
 import DynamicPolynomials
 @testset "DynamicPolynomials" begin
-    DynamicPolynomials.@polyvar x
-    TestNull.runtests(x)
+    DynamicPolynomials.@polyvar x y
+    TestNull.runtests(x, y)
 end
 
 import TypedPolynomials
 @testset "TypedPolynomials" begin
-    TypedPolynomials.@polyvar x
-    TestNull.runtests(x)
+    TypedPolynomials.@polyvar x y
+    TestNull.runtests(x, y)
 end
diff --git a/test/utils.jl b/test/utils.jl
new file mode 100644
index 0000000..b2ef432
--- /dev/null
+++ b/test/utils.jl
@@ -0,0 +1,7 @@
+function testelements(X, Y, atol)
+    @test length(X) == length(Y)
+    for y in Y
+        @show y
+        @test any(x -> isapprox(x, y, atol = atol), X)
+    end
+end