feat(matrix): implement matrix functions

Startcode/matrix.c

@@ -2,34 +2,161 @@
 #include <string.h>
 #include "matrix.h"
 
-// TODO Matrix-Funktionen implementieren
-
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
-    
+    Matrix matrix = {NULL, 0, 0}; //Initialwerte, da unsicher ob allocierung funktioniert
+
+    if(rows > 0 && cols > 0)
+    {
+        MatrixType *buffer = (MatrixType *)calloc(rows * cols, sizeof(MatrixType));
+        if(buffer != NULL) 
+        {
+            matrix.buffer = buffer;
+            matrix.rows = rows;
+            matrix.cols = cols;
+        }
+    }
+
+    return matrix;
 }
 
 void clearMatrix(Matrix *matrix)
 {
-    
+    if(matrix != NULL)
+    {
+        free(matrix->buffer);
+        matrix->buffer = NULL;
+        matrix->rows = 0;
+        matrix->cols = 0;
+    }
 }
 
 void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    if(rowIdx < matrix.rows && colIdx < matrix.cols)
+    {
+        matrix.buffer[rowIdx * matrix.cols + colIdx] = value;
+    }
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    MatrixType value = UNDEFINED_MATRIX_VALUE;
+
+    if(rowIdx < matrix.rows && colIdx < matrix.cols)
+    {
+        value = matrix.buffer[rowIdx * matrix.cols + colIdx];
+    }
+
+    return value;
+}
+
+static int isValidMatrix(const Matrix matrix)
+{
+    return matrix.buffer != NULL && matrix.rows > 0 && matrix.cols > 0;
+}
+
+static int hasSameDimensions(const Matrix matrix1, const Matrix matrix2)
+{
+    return matrix1.rows == matrix2.rows && matrix1.cols == matrix2.cols;
+}
+
+static int isColumnVector(const Matrix matrix)
+{
+    return matrix.cols == 1;
+}
+
+static Matrix addElementWise(const Matrix matrix1, const Matrix matrix2)
+{
+    Matrix result = createMatrix(matrix1.rows, matrix1.cols);
+
+    if(isValidMatrix(result))
+    {
+        for(unsigned int i = 0; i < matrix1.rows * matrix1.cols; i++)
+        {
+            result.buffer[i] = matrix1.buffer[i] + matrix2.buffer[i];
+        }
+    }
+
+    return result;
+}
+
+static Matrix addBroadcast(const Matrix matrix, const Matrix vector)
+{
+    Matrix result = createMatrix(matrix.rows, matrix.cols);
+
+    if(isValidMatrix(result))
+    {
+        for(unsigned int rowIdx = 0; rowIdx < matrix.rows; rowIdx++)
+        {
+            for(unsigned int colIdx = 0; colIdx < matrix.cols; colIdx++)
+            {
+                unsigned int index = rowIdx * matrix.cols + colIdx;
+                result.buffer[index] = matrix.buffer[index] + getMatrixAt(vector, rowIdx, 0);
+            }
+        }
+    }
+
+    return result;
 }
 
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    Matrix result = {NULL, 0, 0}; //leere Matrix als Fehlerfall
+
+    if(isValidMatrix(matrix1) && isValidMatrix(matrix2))
+    {
+        //normal add
+        if(hasSameDimensions(matrix1, matrix2))
+        {
+            result = addElementWise(matrix1, matrix2);
+        }
+        //add Broadcast matrix2 = vektor and matrix1 = matrix
+        else if(isColumnVector(matrix2) && matrix1.rows == matrix2.rows)
+        {
+            result = addBroadcast(matrix1, matrix2);
+        }
+        //add Broadcast matrix1 = vektor and matrix2 = matrix
+        else if(isColumnVector(matrix1) && matrix1.rows == matrix2.rows)
+        {
+            result = addBroadcast(matrix2, matrix1);
+        }
+    }
+
+    return result;
 }
 
+/* (Bedingung: matrix1.cols == matrix2.rows)
+ * | 1 2 3 |   | 7  8  |   | 1*7+2*9+3*11  1*8+2*10+3*12 |   |  58  64 |
+ * | 4 5 6 | * | 9  10 | = | 4*7+5*9+6*11  4*8+5*10+6*12 | = | 139 154 |
+ *             | 11 12 |
+ */
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    Matrix result = {NULL, 0, 0}; //leere Matrix als Fehlerfall
+
+    if(isValidMatrix(matrix1) && isValidMatrix(matrix2) && matrix1.cols == matrix2.rows)
+    {
+        result = createMatrix(matrix1.rows, matrix2.cols);
+
+        if(isValidMatrix(result))
+        {
+            for(unsigned int rowIdx = 0; rowIdx < matrix1.rows; rowIdx++)
+            {
+                for(unsigned int colIdx = 0; colIdx < matrix2.cols; colIdx++)
+                {
+                    MatrixType sum = 0;
+
+                    for(unsigned int k = 0; k < matrix1.cols; k++)
+                    {
+                        sum += getMatrixAt(matrix1, rowIdx, k) * getMatrixAt(matrix2, k, colIdx);
+                    }
+
+                    setMatrixAt(sum, result, rowIdx, colIdx);
+                }
+            }
+        }
+    }
+
+    return result;
 }

Startcode/matrix.h

@@ -3,9 +3,14 @@
 
 #define UNDEFINED_MATRIX_VALUE 0
 
-typedef float MatrixType;
+typedef float MatrixType; //sets the datatype of the matrix
 
-// TODO Matrixtyp definieren
+typedef struct
+{
+    MatrixType *buffer;
+    unsigned int rows;
+    unsigned int cols;
+} Matrix;
 
 
 Matrix createMatrix(unsigned int rows, unsigned int cols);