add cwiseAbs() functionality to DataContainer

elsa/core/DataContainer.h

@@ -577,6 +577,19 @@ namespace elsa
         }
     }
 
+    /// Element-wise absolute value operation
+    template <typename Operand, typename = std::enable_if_t<isDcOrExpr<Operand>>>
+    auto cwiseAbs(Operand const& operand)
+    {
+        auto abs = [](auto const& operand) { return (operand.array().abs()).matrix(); };
+#ifdef ELSA_CUDA_VECTOR
+        auto absGPU = [](auto const& operand, bool) { return quickvec::cwiseAbs(operand); };
+        return Expression{Callables{abs, absGPU}, operand};
+#else
+        return Expression{abs, operand};
+#endif
+    }
+
     /// Element-wise square operation
     template <typename Operand, typename = std::enable_if_t<isDcOrExpr<Operand>>>
     auto square(Operand const& operand)

elsa/core/tests/test_DataContainer.cpp

@@ -279,6 +279,10 @@ TEST_CASE_TEMPLATE_DEFINE("DataContainer: Testing element-wise access", TestType
 
             THEN("the element-wise unary operations work as expected")
             {
+                DataContainer dcAbs = cwiseAbs(dc);
+                for (index_t i = 0; i < dc.getSize(); ++i)
+                    REQUIRE_UNARY(checkApproxEq(dcAbs[i], randVec.array().abs()[i]));
+
                 DataContainer dcSquare = square(dc);
                 for (index_t i = 0; i < dc.getSize(); ++i)
                     REQUIRE_UNARY(checkApproxEq(dcSquare[i], randVec.array().square()[i]));