fix edge case with M1

Author: dlfivefifty

src/logkernelsquare.jl

@@ -34,7 +34,7 @@ function m_const(k, z)
 end
 
 M0(z) = L0(-im*float(z)) + m_const(0, float(z))
-M1(z, r0=L0(-im*z)) = L1(-im*float(z), r0) + m_const(1, float(z))
+M1(z, r0=L0(-im*float(z))) = L1(-im*float(z), r0) + m_const(1, float(z))
 
 
 """

test/runtests.jl

@@ -1,5 +1,9 @@
 using MultivariateSingularIntegrals, QuadGK, ClassicalOrthogonalPolynomials, LinearAlgebra, DoubleFloats, Test
+import MultivariateSingularIntegrals: M1
 
+@testset "L and M" begin
+    @test M1(-2im) ≈ M1(-2im+eps()) ≈ M1(-2im-eps())
+end
 
 Z̃ = (2.0, 2.0im, 2.0+2im, 2.0-2im, -2.0 - 2im)
 Z = (2, 2im, 2+2im, 2-2im, -2 - 2im, -1.001-1.5im, -0.999-1.5im, -0.5-2im, -1-1.5im, -2+2im, -2, 0.1+0.2im, 0.1+im, 0.1-im, 1+0.1im, -1+0.1im, 1+im, -1+im, -1-im, 1-im)