Abs of complex number

fintarin · Aug 26, 2023 · f24a078 · f24a078
1 parent 07bc0c2
commit f24a078
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Showing 4 changed files with 32 additions and 16 deletions.
diff --git a/include/fintamath/numbers/ComplexFunctions.hpp b/include/fintamath/numbers/ComplexFunctions.hpp
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "fintamath/numbers/Complex.hpp"
+#include "fintamath/numbers/Rational.hpp"
+
+namespace fintamath {
+
+Complex abs(const Complex &rhs);
+
+}
diff --git a/src/fintamath/functions/arithmetic/Abs.cpp b/src/fintamath/functions/arithmetic/Abs.cpp
@@ -1,5 +1,7 @@
 #include "fintamath/functions/arithmetic/Abs.hpp"
 
+#include "fintamath/functions/powers/Sqrt.hpp"
+#include "fintamath/numbers/Complex.hpp"
 #include "fintamath/numbers/Integer.hpp"
 #include "fintamath/numbers/IntegerFunctions.hpp"
 #include "fintamath/numbers/Rational.hpp"
@@ -31,6 +33,12 @@ std::unique_ptr<IMathObject> Abs::multiAbsSimplify(const INumber &rhs) {
       return abs(inRhs).toMinimalObject();
     });
 
+    outMultiAbs.add<Complex>([](const Complex &inRhs) {
+      // https://en.wikipedia.org/wiki/Absolute_value#Complex_numbers
+      auto sumOfSquares = *(inRhs.real() * inRhs.real()) + *(inRhs.imag() * inRhs.imag());
+      return Sqrt()(*sumOfSquares);
+    });
+
     return outMultiAbs;
   }();
 

diff --git a/tests/src/expressions/ExpressionTests.cpp b/tests/src/expressions/ExpressionTests.cpp
@@ -952,10 +952,9 @@ TEST(ExpressionTests, stringConstructorTest) {
   EXPECT_EQ(Expression("asin(2)").toString(), "asin(2)");
   EXPECT_EQ(Expression("acos(2)").toString(), "acos(2)");
 
-  // TODO! implement abs
-  EXPECT_EQ(Expression("abs(I)").toString(), "abs(I)");
-  EXPECT_EQ(Expression("abs(I + 1)").toString(), "abs(1 + I)");
-  EXPECT_EQ(Expression("abs(3I + 2)").toString(), "abs(2 + 3 I)");
+  EXPECT_EQ(Expression("abs(I)").toString(), "1");
+  EXPECT_EQ(Expression("abs(I + 1)").toString(), "sqrt(2)");
+  EXPECT_EQ(Expression("abs(3I + 2)").toString(), "sqrt(13)");
 
   // TODO: implement
   EXPECT_EQ(Expression("sin(I + 1)").toString(), "sin(1 + I)");

diff --git a/tests/src/functions/arithmetic/AbsTests.cpp b/tests/src/functions/arithmetic/AbsTests.cpp
@@ -35,18 +35,17 @@ TEST(AbsTests, callTest) {
   EXPECT_EQ(f(Real("8465132.321651651"))->toString(), "8465132.321651651");
   EXPECT_EQ(f(Real("-98465136846516354684651.351"))->toString(), "98465136846516354684651.351");
 
-  // TODO! implement
-  EXPECT_EQ(f(Complex(2, 0))->toString(), "abs(2)");
-  EXPECT_EQ(f(Complex(0, 2))->toString(), "abs(2 I)");
-  EXPECT_EQ(f(Complex(2, 2))->toString(), "abs(2 + 2 I)");
-  EXPECT_EQ(f(Complex(3, 2))->toString(), "abs(3 + 2 I)");
-  EXPECT_EQ(f(Complex(2, 3))->toString(), "abs(2 + 3 I)");
-  EXPECT_EQ(f(Complex(-2, 0))->toString(), "abs(-2)");
-  EXPECT_EQ(f(Complex(0, -2))->toString(), "abs(-2 I)");
-  EXPECT_EQ(f(Complex(2, -2))->toString(), "abs(2 - 2 I)");
-  EXPECT_EQ(f(Complex(-3, 2))->toString(), "abs(-3 + 2 I)");
-  EXPECT_EQ(f(Complex(2, -3))->toString(), "abs(2 - 3 I)");
-  EXPECT_EQ(f(Complex(-2, -3))->toString(), "abs(-2 - 3 I)");
+  EXPECT_EQ(f(Complex(2, 0))->toString(), "2");
+  EXPECT_EQ(f(Complex(0, 2))->toString(), "2");
+  EXPECT_EQ(f(Complex(2, 2))->toString(), "2 sqrt(2)");
+  EXPECT_EQ(f(Complex(3, 2))->toString(), "sqrt(13)");
+  EXPECT_EQ(f(Complex(2, 3))->toString(), "sqrt(13)");
+  EXPECT_EQ(f(Complex(-2, 0))->toString(), "2");
+  EXPECT_EQ(f(Complex(0, -2))->toString(), "2");
+  EXPECT_EQ(f(Complex(2, -2))->toString(), "2 sqrt(2)");
+  EXPECT_EQ(f(Complex(-3, 2))->toString(), "sqrt(13)");
+  EXPECT_EQ(f(Complex(2, -3))->toString(), "sqrt(13)");
+  EXPECT_EQ(f(Complex(-2, -3))->toString(), "sqrt(13)");
 
   EXPECT_EQ(f(Variable("a"))->toString(), "abs(a)");