Kommentare angepasst

matrix.c

@@ -6,20 +6,18 @@
 
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
+    Matrix matrix = {NULL, 0, 0};
 
-    Matrix m = {NULL, rows, cols}; // Wahrscheinlich in Programm bereits enthalten;
+    if (rows == 0 || cols == 0)
+        return matrix;   //gibt leere Matrix zurück
 
-    if (rows > 0 && cols > 0)
-    {
-        m.buffer = (MatrixType *)calloc(rows * cols, sizeof(MatrixType));
-        if (m.buffer == NULL)
-        {
-            m.rows = 0;
-            m.cols = 0;
-        }
-    }
+    matrix.buffer = (MatrixType *)calloc(rows * cols, sizeof(MatrixType));
+    if (matrix.buffer == NULL) //auf verfügbaren Speicherplatz prüfen
+        return matrix;
 
-    return m;
+    matrix.rows = rows;  
+    matrix.cols = cols;
+    return matrix;   //Matrix zurückgeben
 }
 
 void clearMatrix(Matrix *matrix)
@@ -27,18 +25,18 @@ void clearMatrix(Matrix *matrix)
 
     if (matrix != NULL)
     {
-        free(matrix->buffer);
-        matrix->buffer = NULL;
+        free(matrix->buffer);   //Speicherplatz bereinigen
+        matrix->buffer = NULL;  //Werte auf 0 setzen
         matrix->rows = 0;
         matrix->cols = 0;
     }
 }
 
-void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
-// Matrix matrix zu Matrix *matrix, empfehlung
+void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx) 
 {
-    if (rowIdx < matrix.rows && colIdx < matrix.cols && matrix.buffer != NULL)
-        matrix.buffer[rowIdx * matrix.cols + colIdx] = value;
+    if (rowIdx < matrix.rows && colIdx < matrix.cols && matrix.buffer != NULL) //Prüft ob Zugriff möglich
+        matrix.buffer[rowIdx * matrix.cols + colIdx] = value; 
+        //schreibt 2D element in 1D Liste: Element_Reihe*Matrix_Spalten + Element_Spalte
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
@@ -49,53 +47,77 @@ MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int co
 }
 
 // TODO: Funktionen implementieren
-
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
-    // test, if two matrix has exact size
-
-    if (matrix1.rows != matrix2.rows || matrix1.cols != matrix2.cols)
-        return createMatrix(0, 0);
-
-    Matrix result_add = createMatrix(matrix1.rows, matrix1.cols);
-
-    for (int r = 0; r < matrix1.rows; r++)
+    //  immer Probe, gleiche Zeilen der Matrizen
+    // "Elementweise Addition": Probe, ob matrix gleiche größe hat
+    if (matrix1.rows == matrix2.rows && matrix1.cols == matrix2.cols)
     {
-        for (int c = 0; c < matrix1.cols; c++)
+        Matrix result_add = createMatrix(matrix1.rows, matrix1.cols);
+        for (int r = 0; r < matrix1.rows; r++)
         {
-            // TODO: matrix_add initialisieren
-            // matrix_add[r][c] = matrix1[r][c] + matrix2[r][c]
-
-            MatrixType sum = getMatrixAt(matrix1, r, c) + getMatrixAt(matrix2, r, c);
-            setMatrixAt(sum, result_add, r, c); // evtl re
+            for (int c = 0; c < matrix1.cols; c++)
+            {
+                // first version: matrix_add[r][c] = matrix1[r][c] + matrix2[r][c]
+                MatrixType sum = getMatrixAt(matrix1, r, c) + getMatrixAt(matrix2, r, c);
+                setMatrixAt(sum, result_add, r, c);
+            }
         }
+        return result_add;
     }
-    return result_add;
+    // "Broadcasting": matrix1 hat 1 Spalte
+    if (matrix1.rows == matrix2.rows && matrix1.cols == 1)
+    {
+        Matrix result_add = createMatrix(matrix1.rows, matrix2.cols);
+        for (int r = 0; r < matrix1.rows; r++)
+        {
+            for (int c = 0; c < matrix2.cols; c++)
+            {
+                MatrixType sum = getMatrixAt(matrix2, r, c) + getMatrixAt(matrix1, r, 0);
+                setMatrixAt(sum, result_add, r, c);
+            }
+        }
+        return result_add;
+    }
+    // "Broadcasting": matrix2 hat 1 Spalte
+    if (matrix1.rows == matrix2.rows && matrix2.cols == 1)
+    {
+        Matrix result_add = createMatrix(matrix1.rows, matrix1.cols);
+        for (int r = 0; r < matrix1.rows; r++)
+        {
+            for (int c = 0; c < matrix1.cols; c++)
+            {
+                MatrixType sum = getMatrixAt(matrix1, r, c) + getMatrixAt(matrix2, r, 0);
+                setMatrixAt(sum, result_add, r, c);
+            }
+        }
+        return result_add;
+    }
+
+    return createMatrix(0, 0);
 }
 
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    // Needed: rows/Zeilen, collums/Spalten
     MatrixType buffer_add;
-    // Probe ob Spalten1 = Zeilen2
-    if (matrix1.cols != matrix2.rows)
+    
+    if (!matrix1.buffer || !matrix2.buffer) // Probe ob leere Matrize vorliegt 
+        return createMatrix(0, 0);
+    if (matrix1.cols != matrix2.rows) // Probe ob Spalten1 = Zeilen2
         return createMatrix(0, 0);
 
-    Matrix result_mul = createMatrix(matrix1.rows, matrix2.cols); // ""
+    Matrix result_mul = createMatrix(matrix1.rows, matrix2.cols);
 
-    for (int index = 0; index < matrix1.rows; index++)
+    for (unsigned int index = 0; index < matrix1.rows; index++)
     {
-        for (int shift = 0; shift < matrix2.cols; shift++)
+        for (unsigned int shift = 0; shift < matrix2.cols; shift++)
         {
             buffer_add = 0;
-            for (int skalar = 0; skalar < matrix1.cols; skalar++)
-            // TODO: matrix_add initialisieren
+            for (unsigned int skalar = 0; skalar < matrix1.cols; skalar++)
             {
-                // buffer_add += matrix1[index][skalar]*matrix2[skalar][index];
                 buffer_add += getMatrixAt(matrix1, index, skalar) * getMatrixAt(matrix2, skalar, shift);
             }
-            // matrix_mul[index][shift] = buffer_add;
-            setMatrixAt(buffer_add, result_mul, index, shift); // result als Pointer, also mit &result
+            setMatrixAt(buffer_add, result_mul, index, shift);
         }
     }
     return result_mul;