improved accuracy Debye_function

MartinMikkelsen · Mar 8, 2024 · c286bac · c286bac
1 parent 647e539
commit c286bac
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Showing 5 changed files with 8 additions and 8 deletions.
diff --git a/.DS_Store b/.DS_Store
diff --git a/.github/.DS_Store b/.github/.DS_Store
diff --git a/docs/.DS_Store b/docs/.DS_Store
diff --git a/src/Debye.jl b/src/Debye.jl
@@ -10,7 +10,7 @@ The Debye function(n,x) given by
 Returns the value ``D(n,x)``
 """
 function Debye_function(n,x,min_tol=1e-5)
-    D = n./(x.^n).*quadgk(t -> (t.^n)/(exp.(t)-1),min_tol,x)[1]
+    D = n./(x.^n).*quadgk(t -> (t.^n)/(expm1.(t)),min_tol,x)[1]
     return D    
 end
 export Debye_function
diff --git a/test/runtests.jl b/test/runtests.jl
@@ -14,16 +14,16 @@ using Test
     @test FewSpecialFunctions.Debye_function(1.0, 0.2) ≈ 0.951111 atol = 1e-4
 
     @test FewSpecialFunctions.Debye_function(1.0, 1.0) ≈ 0.777505 atol = 1e-4
-    @test FewSpecialFunctions.Debye_function(1.0, 1.3) ≈ 0.721173 atol = 1e-4
+    @test FewSpecialFunctions.Debye_function(1.0, 1.3) ≈ 0.721173 atol = 1e-5
 
-    @test FewSpecialFunctions.Debye_function(1.0, 2.6) ≈ 0.526375 atol = 1e-4
-    @test FewSpecialFunctions.Debye_function(1.0, 2.8) ≈ 0.502682 atol = 1e-4
+    @test FewSpecialFunctions.Debye_function(1.0, 2.6) ≈ 0.526375 atol = 1e-5
+    @test FewSpecialFunctions.Debye_function(1.0, 2.8) ≈ 0.502682 atol = 1e-5
 
-    @test FewSpecialFunctions.Debye_function(2.0, 1.3) ≈ 0.635800 atol = 1e-4
-    @test FewSpecialFunctions.Debye_function(2.0, 2.8) ≈ 0.368324 atol = 1e-4
+    @test FewSpecialFunctions.Debye_function(2.0, 1.3) ≈ 0.635800 atol = 1e-5
+    @test FewSpecialFunctions.Debye_function(2.0, 2.8) ≈ 0.368324 atol = 1e-5
 
-    @test FewSpecialFunctions.Debye_function(3.0, 0.7) ≈ 0.761859 atol = 1e-4
-    @test FewSpecialFunctions.Debye_function(3.0, 2.8) ≈ 0.309995 atol = 1e-4
+    @test FewSpecialFunctions.Debye_function(3.0, 0.7) ≈ 0.761859 atol = 1e-5
+    @test FewSpecialFunctions.Debye_function(3.0, 2.8) ≈ 0.309995 atol = 1e-5
 
     @test FewSpecialFunctions.Fresnel_S_integral_pi(0.10) ≈ 0.0005236 atol = 1e-4
     @test FewSpecialFunctions.Fresnel_S_integral_pi(0.32) ≈ 0.0171256 atol = 1e-4