fixed previously missed bug

.gitignore

@@ -1,4 +1,5 @@
 mnist
 runTests
+runMatrixTests
 *.o
 *.exe

matrix.c

@@ -4,28 +4,24 @@
 
 // TODO Matrix-Funktionen implementieren
 
-typedef struct Matrix {
-    unsigned int xElement;
-    unsigned int yElement;
-    int ** data;
-} Matrix;
-
+/*
+Alte Funktion
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
     Matrix m;
-    m.xElement = rows;
-    m.yElement = cols;
+    m.rows = rows;
+    m.cols = cols;
     m.data = NULL;
 
     if(rows == 0 || cols == 0){
-        m.xElement = m.yElement = 0;
+        m.rows = m.cols = 0;
         return m;
     }
 
     m.data = malloc(rows * sizeof *m.data);
     
     if(!m.data){
-        m.xElement = m.yElement = 0;
+        m.rows = m.cols = 0;
         return m;
     }
     for(unsigned int i = 0; i < rows; i++){
@@ -37,35 +33,114 @@ Matrix createMatrix(unsigned int rows, unsigned int cols)
         }
         free(m.data);
         m.data = NULL;
-        m.xElement = m.yElement = 0;
+        m.rows = m.cols = 0;
         return m;
       }
         
     }
     return m;
 }
+*/
+
+Matrix createMatrix(size_t rows, size_t cols)
+{
+    Matrix m;
+    m.rows = rows;
+    m.cols = cols;
+    m.buffer = NULL;
+
+    if(rows == 0 || cols == 0){
+        m.rows = m.cols = 0;
+        return m;
+    }
+
+    // Single allocation for entire matrix
+    m.buffer = malloc(rows * cols * sizeof(MatrixType));
+    
+    if(!m.buffer){
+        m.rows = m.cols = 0;
+        return m;
+    }
+    
+    // Initialize (optional)
+    for(unsigned int i = 0; i < rows * cols; i++){
+        m.buffer[i] = UNDEFINED_MATRIX_VALUE;
+    }
+    
+    return m;
+}
 
 void clearMatrix(Matrix *matrix)
 {
+    for (int i = 0; i < matrix->rows; i++) {
+        for (int j = 0; j < matrix->cols;j++) {
+            matrix->buffer[i + matrix->rows* j] = UNDEFINED_MATRIX_VALUE;
+        }
+    }
+    free(matrix->buffer);
+    matrix->rows = 0;
+    matrix->cols = 0;
     
 }
 
 void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    matrix.buffer[rowIdx-1 + matrix.rows*(colIdx-1)] = value;
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    MatrixType returnVal;
+    returnVal = matrix.buffer[rowIdx-1 + matrix.rows*(colIdx-1)];
+    return returnVal;
 }
 
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    //check if the matrices are able to be added (same size)
+    if (matrix1.cols == matrix2.cols && matrix1.rows == matrix2.rows){
+        //size of the matrices should be the same, if the addition is supposed to happen
+        Matrix outputMatrix = createMatrix(matrix1.rows, matrix1.cols);
+        for (int i = 0; i < matrix1.rows;i++) {
+            for (int j = 0; j < matrix1.cols; j++) {
+                // how this should work in normal Matrix version:
+                // outputmatrix.buffer[i][j] = matrix1.buffer[i][j] + matrix2.buffer[i][j];
+                outputMatrix.buffer[i + outputMatrix.rows* j] = matrix1.buffer[i + matrix1.rows* j] + matrix2.buffer[i + matrix2.rows * j];
+            }
+        }
+        return outputMatrix;
+    } else {
+        //the matrix could not be added, since the matrix sizes are not set correct.
+        Matrix m;
+        m.rows = 0; 
+        m.cols = 0;
+        m.buffer = NULL;
+        return m;
+    }
+
 }
 
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    //check, if the matrices can be multiplied
+    if (matrix1.rows == matrix2.cols) {
+        Matrix outputMatrix = createMatrix(matrix1.rows, matrix2.cols);
+        for(int i = 0; i < matrix1.rows; i++) {
+            for (int j = 0; j < matrix2.cols; j++) {
+                for (int k = 0; k < matrix2.rows; k++) {
+                    // how this should work in normal Matrix version:
+                    // outputMatrix.buffer[i][j] = matrix1.buffer[i][k] * matrix2.buffer[k][j];
+                    outputMatrix.buffer[i + outputMatrix.rows* j] = matrix1.buffer[i + matrix1.rows* k] * matrix2.buffer[k + matrix2.rows*j];
+                }
+            }
+        }
+        return outputMatrix;
+    } else {
+        //the matrix could not be added, since the matrix sizes are not set correct.
+        Matrix m;
+        m.rows = 0; 
+        m.cols = 0;
+        m.buffer = NULL;
+        return m;
+    }
 }

matrix.h

@@ -4,11 +4,16 @@
 #define UNDEFINED_MATRIX_VALUE 0
 
 typedef float MatrixType;
-
 // TODO Matrixtyp definieren
 
+typedef struct Matrix {
+    size_t rows; //X-Element
+    size_t cols; //Y-Element
+    MatrixType *buffer;
+} Matrix;
 
-Matrix createMatrix(unsigned int rows, unsigned int cols);
+
+Matrix createMatrix(size_t rows, size_t cols);
 void clearMatrix(Matrix *matrix);
 void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx);
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx);