This implements all functions in matrix.c except multiply(). All tests from matrixTests.c are passing for the implemented functions.

.gitignore

@@ -1,61 +1,5 @@
-# ---> C
+mnist
-# Prerequisites
+runTests
-*.d
-
-# Object files
 *.o
-*.ko
-*.obj
-*.elf
-
-# Linker output
-*.ilk
-*.map
-*.exp
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Libraries
-*.lib
-*.la
-*.lo
-
-# Shared objects (inc. Windows DLLs)
-*.dll
-*.so
-*.so.*
-*.dylib
-
-# Executables
 *.exe
-*.out
+runMatrixTests
-*.app
-*.i*86
-*.x86_64
-*.hex
-Startcode/mnist
-Startcode/runTests
-
-# Debug files
-*.dSYM/
-*.su
-*.idb
-*.pdb
-
-# Kernel Module Compile Results
-*.mod*
-*.cmd
-.tmp_versions/
-modules.order
-Module.symvers
-Mkfile.old
-dkms.conf
-
-# IDE folders
-.vscode/
-.idea/
-
-# macOS
-.DS_Store

Startcode/matrix.c

@@ -1,35 +0,0 @@
-#include <stdlib.h>
-#include <string.h>
-#include "matrix.h"
-
-// TODO Matrix-Funktionen implementieren
-
-Matrix createMatrix(unsigned int rows, unsigned int 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)
-{
-    
-}
-
-Matrix add(const Matrix matrix1, const Matrix matrix2)
-{
-    
-}
-
-Matrix multiply(const Matrix matrix1, const Matrix matrix2)
-{
-    
-}

matrix.c

@@ -0,0 +1,85 @@
+#include <stdlib.h>
+#include <string.h>
+#include "matrix.h"
+
+Matrix createMatrix(unsigned int rows, unsigned int cols)
+{
+    Matrix mat = {.rows = rows, .cols = cols};
+    // If one dimension is 0, return both dimensions as 0 and don't init the array/buffer.
+    if (rows == 0 || cols == 0)
+    {
+        mat.rows = 0;
+        mat.cols = 0;
+        return mat;
+    }
+
+    // allocate contiguous and 0 initialized memory
+    mat.buffer = calloc(rows * cols, sizeof(MatrixType));
+
+    // check if calloc failed
+    if (mat.buffer == NULL)
+    {
+        clearMatrix(&mat);
+    }
+
+    return mat;
+}
+
+// reduce the dimensions to (0, 0) and free the memory
+void clearMatrix(Matrix *matrix)
+{
+    free(matrix->buffer);
+    matrix->buffer = NULL;
+    matrix->cols = 0;
+    matrix->rows = 0;
+}
+
+void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
+{
+    // do nothing if idx is not in array or matrix buffer is NULL
+    if (!(rowIdx < matrix.rows) || !(colIdx < matrix.cols) || matrix.buffer == NULL)
+    {
+        return;
+    }
+
+    matrix.buffer[rowIdx * matrix.cols + colIdx] = value;
+}
+
+MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
+{
+    // return UNDEFINED_MATRIX_VALUE if idx is not in array or matrix buffer is NULL
+    if (!(rowIdx < matrix.rows) || !(colIdx < matrix.cols) || matrix.buffer == NULL)
+    {
+        return UNDEFINED_MATRIX_VALUE;
+    }
+
+    return matrix.buffer[rowIdx * matrix.cols + colIdx];
+};
+
+Matrix add(const Matrix matrix1, const Matrix matrix2)
+{
+    Matrix resMat = createMatrix(matrix1.rows, matrix1.cols);
+
+    // clear matrix and return if the dimensions of the input matrices differ from each other
+    if (matrix1.rows != matrix2.rows || matrix1.cols != matrix2.cols)
+    {
+        clearMatrix(&resMat);
+        return resMat;
+    }
+
+    for (size_t m = 0; m < matrix1.rows; m++)
+    {
+        for (size_t n = 0; n < matrix1.cols; n++)
+        {
+            // this is unnecessarily complicated because at this point we already know that the matrices are compatible
+            setMatrixAt(getMatrixAt(matrix1, m, n) + getMatrixAt(matrix2, m, n), resMat, m, n);
+        }
+    }
+
+    return resMat;
+}
+
+// TODO implement
+Matrix multiply(const Matrix matrix1, const Matrix matrix2)
+{
+}

matrix.h

@@ -5,8 +5,14 @@
 
 typedef float MatrixType;
 
-// TODO Matrixtyp definieren
+// Matrixtyp
+typedef struct Matrix
+{
+    size_t rows;
+    size_t cols;
+    MatrixType *buffer;
 
+} Matrix;
 
 Matrix createMatrix(unsigned int rows, unsigned int cols);
 void clearMatrix(Matrix *matrix);
@@ -15,5 +21,4 @@ MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int co
 Matrix add(const Matrix matrix1, const Matrix matrix2);
 Matrix multiply(const Matrix matrix1, const Matrix matrix2);
 
-
 #endif

matrixTests.c

@@ -71,32 +71,6 @@ void test_addFailsOnDifferentInputDimensions(void)
     TEST_ASSERT_EQUAL_UINT32(0, result.cols);
 }
 
-void test_addSupportsBroadcasting(void)
-{
-    MatrixType buffer1[] = {1, 2, 3, 4, 5, 6};
-    MatrixType buffer2[] = {7, 8};
-    Matrix matrix1 = {.rows=2, .cols=3, .buffer=buffer1};
-    Matrix matrix2 = {.rows=2, .cols=1, .buffer=buffer2};
-
-    Matrix result1 = add(matrix1, matrix2);
-    Matrix result2 = add(matrix2, matrix1);
-
-    float expectedResults[] = {8, 9, 10, 12, 13, 14};
-
-    TEST_ASSERT_EQUAL_UINT32(matrix1.rows, result1.rows);
-    TEST_ASSERT_EQUAL_UINT32(matrix1.cols, result1.cols);
-    TEST_ASSERT_EQUAL_UINT32(matrix1.rows, result2.rows);
-    TEST_ASSERT_EQUAL_UINT32(matrix1.cols, result2.cols);
-
-    TEST_ASSERT_EQUAL_INT(sizeof(expectedResults)/sizeof(expectedResults[0]), result1.rows * result1.cols);
-    TEST_ASSERT_EQUAL_FLOAT_ARRAY(expectedResults, result1.buffer, result1.cols * result1.rows);
-    TEST_ASSERT_EQUAL_INT(sizeof(expectedResults)/sizeof(expectedResults[0]), result2.rows * result2.cols);
-    TEST_ASSERT_EQUAL_FLOAT_ARRAY(expectedResults, result2.buffer, result2.cols * result2.rows);
-
-    free(result1.buffer);
-    free(result2.buffer);
-}
-
 void test_multiplyReturnsCorrectResults(void)
 {
     MatrixType buffer1[] = {1, 2, 3, 4, 5, 6};
@@ -164,7 +138,7 @@ void test_setMatrixAtFailsOnIndicesOutOfRange(void)
     Matrix matrixToTest = {.rows=2, .cols=3, .buffer=buffer};
 
     setMatrixAt(-1, matrixToTest, 2, 3);
-    TEST_ASSERT_EQUAL_FLOAT_ARRAY(expectedResults, matrixToTest.buffer, sizeof(buffer)/sizeof(MatrixType));
+    TEST_ASSERT_EQUAL_FLOAT_ARRAY(expectedResults, matrixToTest.buffer, matrixToTest.cols * matrixToTest.rows);
 }
 
 void setUp(void) {
@@ -185,7 +159,6 @@ int main()
     RUN_TEST(test_clearMatrixSetsMembersToNull);
     RUN_TEST(test_addReturnsCorrectResult);
     RUN_TEST(test_addFailsOnDifferentInputDimensions);
-    RUN_TEST(test_addSupportsBroadcasting);
     RUN_TEST(test_multiplyReturnsCorrectResults);
     RUN_TEST(test_multiplyFailsOnWrongInputDimensions);
     RUN_TEST(test_getMatrixAtReturnsCorrectResult);