Merge pull request #50 from rajithv/abs

Abs

Author: isuruf

ext/symengine/symengine.c

@@ -114,6 +114,9 @@ void Init_symengine() {
     c_zeta = rb_define_class_under(m_symengine, "Zeta", c_function);
     c_gamma = rb_define_class_under(m_symengine, "Gamma", c_function);
 
+    //Abs Class
+    c_abs = rb_define_class_under(m_symengine, "Abs", c_function);
+
     //TrigFunction SubClasses
     c_sin = rb_define_class_under(m_symengine, "Sin", c_trig_function);
     c_cos = rb_define_class_under(m_symengine, "Cos", c_trig_function);

ext/symengine/symengine.h

@@ -25,6 +25,7 @@ VALUE c_lambertw;
 VALUE c_dirichlet_eta;
 VALUE c_zeta;
 VALUE c_gamma;
+VALUE c_abs;
 VALUE c_sin;
 VALUE c_cos;
 VALUE c_tan;

ext/symengine/symengine_utils.c

@@ -101,6 +101,8 @@ VALUE Klass_of_Basic(const basic_struct *basic_ptr) {
             return c_mul;
         case SYMENGINE_POW:
             return c_pow;
+        case SYMENGINE_ABS:
+            return c_abs;
         case SYMENGINE_SIN:
             return c_sin;
         case SYMENGINE_COS:

spec/functions_spec.rb

@@ -2,6 +2,26 @@
   let(:pi) { SymEngine::PI }
   let(:e)  { SymEngine::E  }
   let(:x)  { sym("x")      }
+  let(:y)  { sym("y")      }
+
+  context "Abs" do
+    context "with a symbol" do
+      subject { SymEngine::abs(x)}
+      it { is_expected.to be_a SymEngine::Abs }
+    end
+    context "with an integer" do
+      subject { SymEngine::abs(SymEngine(1))}
+      it { is_expected.to be_a SymEngine::Integer }
+    end
+    context "with a symbol addition" do
+      subject { SymEngine::abs(x+y) }
+      it { is_expected.to be_a SymEngine::Abs }
+    end
+    context "with a function of a symbol" do
+      subject { SymEngine::abs(SymEngine::sin(x)) }
+      it { is_expected.to be_a SymEngine::Abs }
+    end
+  end
 
   context '2*x' do
     [