From 23d56fb3d00684daf6ec846f6fd268d57ba5b099 Mon Sep 17 00:00:00 2001
From: Stefan Eschbach <stefan.eschbach@fau.de>
Date: Thu, 6 Apr 2017 15:51:13 +0200
Subject: [PATCH] Added matrix scalar addition/subtraction (binary and unary) operators.

---
 include/GMatrix.hpp    | 40 ++++++++++++++++++++++++++++++++++++++++
 src/linalg/GMatrix.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+), 0 deletions(-)

diff --git a/include/GMatrix.hpp b/include/GMatrix.hpp
index 3939799..9bfbfc8 100644
--- a/include/GMatrix.hpp
+++ b/include/GMatrix.hpp
@@ -96,11 +96,15 @@ public:
     virtual GMatrix&      operator=(const GMatrix& matrix);
     virtual GMatrix&      operator=(const double& value);
     virtual GMatrix       operator+(const GMatrix& matrix) const;
+    virtual GMatrix       operator+(const double& scalar) const;
     virtual GMatrix       operator-(const GMatrix& matrix) const;
+    virtual GMatrix       operator-(const double& scalar) const;
     virtual GMatrix       operator*(const GMatrix& matrix) const;
     virtual GMatrix       operator-(void) const;
     virtual GMatrix&      operator+=(const GMatrix& matrix);
+    virtual GMatrix&      operator+=(const double& scalar);
     virtual GMatrix&      operator-=(const GMatrix& matrix);
+    virtual GMatrix&      operator-=(const double& scalar);
     virtual GMatrix&      operator*=(const GMatrix& matrix);
     virtual GMatrix&      operator*=(const double& scalar);
     virtual GMatrix&      operator/=(const double& scalar);
@@ -207,6 +211,24 @@ GMatrix GMatrix::operator+(const GMatrix& matrix) const
 
 
 /***********************************************************************//**
+ * @brief Binary matrix scalar addition
+ *
+ * @param[in] double Scalar.
+ * @return Result of matrix addition.
+ *
+ * Returns the sum of the matrix with another matrix were all entries have 
+ * the value of scalar. The method makes use of the unary addition operator.
+ ***************************************************************************/
+inline
+GMatrix GMatrix::operator+(const double& scalar) const
+{
+    GMatrix result = *this;
+    result += scalar;
+    return result;
+}
+
+
+/***********************************************************************//**
  * @brief Binary matrix subtraction
  *
  * @param[in] matrix Matrix.
@@ -225,6 +247,24 @@ GMatrix GMatrix::operator-(const GMatrix& matrix) const
 
 
 /***********************************************************************//**
+ * @brief Binary matrix scalar subtraction
+ *
+ * @param[in] double Scalar.
+ * @return Result of matrix subtraction.
+ *
+ * Returns the difference of the matrix with another matrix were all entries have 
+ * the value of scalar. The method makes use of the unary subtraction operator.
+ ***************************************************************************/
+inline
+GMatrix GMatrix::operator+(const double& scalar) const
+{
+    GMatrix result = *this;
+    result -= scalar;
+    return result;
+}
+
+
+/***********************************************************************//**
  * @brief Binary matrix multiplication
  *
  * @param[in] matrix Matrix.
diff --git a/src/linalg/GMatrix.cpp b/src/linalg/GMatrix.cpp
index 7ccc856..b7a199c 100644
--- a/src/linalg/GMatrix.cpp
+++ b/src/linalg/GMatrix.cpp
@@ -362,6 +362,26 @@ GMatrix& GMatrix::operator+=(const GMatrix& matrix)
 
 
 /***********************************************************************//**
+ * @brief Unary matrix scalar addition operator
+ *
+ * @param[in] double Scalar.
+ *
+ * This method adds a given scalar to each matrix element.
+ ***************************************************************************/
+GMatrix& GMatrix::operator+=(const double& scalar)
+{
+    // Add all matrix elements
+    double* dst = m_data;
+    for (int i = 0; i < m_elements; ++i) {
+        *dst++ += scalar;
+    }
+
+    // Return result
+    return *this;
+}
+
+
+/***********************************************************************//**
  * @brief Unary matrix subtraction operator
  *
  * @param[in] matrix Matrix.
@@ -394,6 +414,26 @@ GMatrix& GMatrix::operator-=(const GMatrix& matrix)
 
 
 /***********************************************************************//**
+ * @brief Unary matrix scalar subtraction operator
+ *
+ * @param[in] double Scalar.
+ *
+ * This method subtracts a given scalar from each matrix element.
+ ***************************************************************************/
+GMatrix& GMatrix::operator+=(const double& scalar)
+{
+    // Add all matrix elements
+    double* dst = m_data;
+    for (int i = 0; i < m_elements; ++i) {
+        *dst++ -= scalar;
+    }
+
+    // Return result
+    return *this;
+}
+
+
+/***********************************************************************//**
  * @brief Unary matrix multiplication operator
  *
  * @param[in] matrix Matrix.
--
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