feat: add conversion from QQBarFieldElem to ComplexF64 (#1892)

Nemocas · Oct 12, 2024 · 8fac1af · 8fac1af
1 parent df3ab65
commit 8fac1af
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diff --git a/src/calcium/qqbar.jl b/src/calcium/qqbar.jl
@@ -1484,6 +1484,17 @@ function ZZRingElem(a::QQBarFieldElem)
   return z
 end
 
+function (::Type{ComplexF64})(x::QQBarFieldElem)
+  z = AcbField(53, cached = false)(x)
+  x = ArbFieldElem()
+  ccall((:acb_get_real, libflint), Nothing, (Ref{ArbFieldElem}, Ref{AcbFieldElem}), x, z)
+  xx = Float64(x)
+  y = ArbFieldElem()
+  ccall((:acb_get_imag, libflint), Nothing, (Ref{ArbFieldElem}, Ref{AcbFieldElem}), y, z)
+  yy = Float64(y)
+  return ComplexF64(xx, yy)
+end
+
 ###############################################################################
 #
 #   Unsafe functions

diff --git a/test/calcium/qqbar-test.jl b/test/calcium/qqbar-test.jl
@@ -389,6 +389,19 @@ end
 
 end
 
+@testset "QQBarFieldElem.conversions" begin
+  R = algebraic_closure(QQ)
+
+  # precision must be < 53, otherwise the test is wrong
+  set_precision!(Balls, 50) do
+    for i in 1:10
+      a = rand(R, degree=5, bits=5)
+      b = ComplexF64(a)
+      @test contains(ComplexField()(a), ComplexField()(b))
+    end
+  end
+end
+
 function test_elem(R::QQBarField)
   return rand(R, degree=5, bits=5)
 end