spec/lib/integrand_spec.rb in dydx-0.1.0 vs spec/lib/integrand_spec.rb in dydx-0.1.1

@@ -28,15 +28,29 @@
   end
 
   it 'ex5' do
     $f = nil
     f(x) <= log(x)
-    expect(S(f(x), dx)[0, 1]).to eq(- Float::INFINITY)
+    expect(S(f(x), dx)[0, 1]).to eq(-oo)
   end
 
-  # TODO
   it 'ex6' do
     $f = nil
-    f(x) <= e ^ (- (x^2))
-    expect(S(f(x), dx)[-100, 100]).to eq(1.672428604536991)
+    f(x) <= e ^ (- (x ^ 2))
+    expect(f(0)).to eq(1)
+    expect(f(1)).to eq(1.0/Math::E)
+    expect(f(1000)).to eq(0)
+    expect(S(f(x), dx)[-1000, 1000, 3000]).to eq(1.7724538506374117)
+  end
+
+  it 'ex7' do
+    $f = nil
+    f(x) <= (1.0 / ( ( 2.0 * Math::PI ) ^ 0.5 ) ) * ( e ^ (- (x ^ 2) / 2) )
+    expect(S(f(x), dx)[-1000, 1000, 1000]).to eq(0.9952054164466917)
+  end
+
+  it 'ex8' do
+    $f = nil
+    f(x) <= (1.0 / ( ( 2.0 * pi ) ^ 0.5 ) ) * ( e ^ (- (x ^ 2) / 2) )
+    expect(S(f(x), dx)[-oo, oo, 1000]).to eq(0.9952054164466917)
   end
 end