make matrix multiplication faster

.gitignore

@@ -2,4 +2,7 @@ mnist
 runTests
 *.o
 *.exe
-runMatrixTests
+runMatrixTests
+runImageInputTests
+runNeuralNetworkTests
+.vscode

imageInput.c

@@ -6,17 +6,156 @@
 #define BUFFER_SIZE 100
 #define FILE_HEADER_STRING "__info2_image_file_format__"
 
-// TODO Implementieren Sie geeignete Hilfsfunktionen für das Lesen der Bildserie aus einer Datei
+typedef enum
+{
+    IMG_SUCCESS = 0,
+    IMG_ERR_INVALID_HEADER, // Header did not match
+    IMG_ERR_READ,           // Failed to read from file, maybe it's too short
+    IMG_ERR,                // General Error
+} ImageError;
+
+static ImageError checkHeader(FILE *file);
+static ImageError readPictureParams(unsigned short *number, unsigned short *width, unsigned short *height, FILE *file);
+static ImageError readImage(size_t numPixels, GrayScalePixelType *pixelBuffer, unsigned char *label, FILE *file);
+static ImageError parseImageFile(FILE *file, GrayScaleImageSeries *series);
 
-// TODO Vervollständigen Sie die Funktion readImages unter Benutzung Ihrer Hilfsfunktionen
 GrayScaleImageSeries *readImages(const char *path)
 {
-    GrayScaleImageSeries *series = NULL;
-    
+    GrayScaleImageSeries *series = calloc(1, sizeof(GrayScaleImageSeries));
+    if (series == NULL)
+    {
+        return NULL;
+    }
+
+    FILE *file = fopen(path, "rb");
+    if (file == NULL)
+    {
+        clearSeries(series);
+        series = NULL;
+        return NULL; // fopen failed
+    }
+
+    if (parseImageFile(file, series))
+    {
+        clearSeries(series);
+        series = NULL;
+    }
+
+    fclose(file);
     return series;
 }
 
-// TODO Vervollständigen Sie die Funktion clearSeries, welche eine Bildserie vollständig aus dem Speicher freigibt
+static ImageError parseImageFile(FILE *file, GrayScaleImageSeries *series)
+{
+    if (checkHeader(file))
+    {
+        return IMG_ERR; // header check failed
+    }
+
+    unsigned short number, width, height;
+    if (readPictureParams(&number, &width, &height, file))
+    {
+        return IMG_ERR; // read failed
+    }
+    size_t pixels = width * height;
+
+    // now setup the image series
+    series->images = calloc(number, sizeof(GrayScaleImage));
+    if (series->images == NULL)
+    {
+        return IMG_ERR;
+    }
+
+    series->labels = malloc(number * sizeof(unsigned char));
+    if (series->labels == NULL)
+    {
+        return IMG_ERR;
+    }
+
+    series->count = number;
+    for (size_t imageIdx = 0; imageIdx < number; imageIdx++)
+    {
+        GrayScaleImage *curImage = &series->images[imageIdx];
+
+        curImage->buffer = malloc(sizeof(GrayScalePixelType) * pixels);
+        if (curImage->buffer == NULL)
+        {
+            return IMG_ERR;
+        }
+
+        curImage->width = width;
+        curImage->height = height;
+
+        if (readImage(pixels, curImage->buffer, &series->labels[imageIdx], file))
+        {
+            return IMG_ERR;
+        }
+    }
+    return IMG_SUCCESS;
+}
+
+static ImageError checkHeader(FILE *file)
+{
+    size_t len = strlen(FILE_HEADER_STRING);
+    char headerBuf[len + 1];
+    size_t charsRead = fread(headerBuf, 1, len, file);
+    if (charsRead < len)
+    {
+        return IMG_ERR_READ;
+    }
+    headerBuf[len] = '\0';
+    return strcmp(headerBuf, FILE_HEADER_STRING) == 0 ? IMG_SUCCESS : IMG_ERR_INVALID_HEADER;
+}
+
+static ImageError readPictureParams(unsigned short *number, unsigned short *width, unsigned short *height, FILE *file)
+{
+    if (1 != fread(number, sizeof(unsigned short), 1, file))
+    {
+        return IMG_ERR_READ;
+    }
+
+    if (1 != fread(width, sizeof(unsigned short), 1, file))
+    {
+        return IMG_ERR_READ;
+    }
+
+    if (1 != fread(height, sizeof(unsigned short), 1, file))
+    {
+        return IMG_ERR_READ;
+    }
+
+    return IMG_SUCCESS;
+}
+
+static ImageError readImage(size_t numPixels, GrayScalePixelType *pixelBuffer, unsigned char *label, FILE *file)
+{
+    if (numPixels > fread(pixelBuffer, sizeof(GrayScalePixelType), numPixels, file))
+    {
+        return IMG_ERR_READ;
+    }
+
+    if (1 != fread(label, sizeof(unsigned char), 1, file))
+    {
+        return IMG_ERR_READ;
+    }
+
+    return IMG_SUCCESS;
+}
+
+// frees memory for each image buffer, image, label and finally series
 void clearSeries(GrayScaleImageSeries *series)
 {
+    if (series)
+    {
+
+        int seriesLen = series->count;
+        for (size_t imageIdx = 0; imageIdx < seriesLen; imageIdx++)
+        {
+            free(series->images[imageIdx].buffer);
+        }
+
+        free(series->images);
+        free(series->labels);
+        free(series);
+    }
 }

matrix.c

@@ -109,7 +109,6 @@ Matrix add(const Matrix matrix1, const Matrix matrix2)
     {
         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);
         }
     }
@@ -117,32 +116,37 @@ Matrix add(const Matrix matrix1, const Matrix matrix2)
     return resMat;
 }
 
-Matrix multiply(const Matrix matrix1, const Matrix matrix2)
+Matrix multiply(const Matrix A, const Matrix B)
 {
-    if (matrix1.cols != matrix2.rows || matrix1.buffer == NULL || matrix2.buffer == NULL)
+    if (A.cols != B.rows || A.buffer == NULL || B.buffer == NULL)
     {
         return createMatrix(0, 0);
     }
 
-    int rows = matrix1.rows, cols = matrix2.cols;
-    Matrix resMat = createMatrix(rows, cols);
+    int rows = A.rows, cols = B.cols;
+    Matrix C = createMatrix(rows, cols);
 
-    if (resMat.buffer == NULL)
+    if (C.buffer == NULL)
     {
         return createMatrix(0, 0);
     }
 
-    for (size_t rowIdx = 0; rowIdx < rows; rowIdx++)
+    // M = Rows, K = Common Dim, N = Cols
+    size_t M = A.rows, K = A.cols, N = B.cols;
+
+    for (size_t i = 0; i < M; i++)
     {
-        for (size_t colIdx = 0; colIdx < cols; colIdx++)
+        for (size_t k = 0; k < K; k++)
+
         {
-            int curCellVal = 0;
-            for (size_t k = 0; k < matrix1.cols; k++)
+            MatrixType valA = A.buffer[i * K + k];
+            for (size_t j = 0; j < N; j++)
             {
-                curCellVal += getMatrixAt(matrix1, rowIdx, k) * getMatrixAt(matrix2, k, colIdx);
+                // C[i, j] += A[i, k] * B[k, j];
+                // M x N,     M x K,    K x N
+                C.buffer[i * N + j] += valA * B.buffer[k * N + j];
             }
-            setMatrixAt(curCellVal, resMat, rowIdx, colIdx);
         }
     }
-    return resMat;
+    return C;
 }

neuralNetworkTests.c

@@ -6,9 +6,30 @@
 #include "neuralNetwork.h"
 
 
+static void erzeugeMatrix(FILE *file, const Matrix *m)
+{
+    fwrite(&m->rows, sizeof(int), 1, file);
+    fwrite(&m->cols, sizeof(int), 1, file);
+    fwrite(m->buffer, sizeof(MatrixType), m->rows * m->cols, file);
+}
+
 static void prepareNeuralNetworkFile(const char *path, const NeuralNetwork nn)
 {
-    // TODO
+    FILE *file = fopen(path, "wb");
+    if (!file)
+        return;
+
+    const char *header = "__info2_neural_network_file_format__";
+    fwrite(header, sizeof(char), strlen(header), file);
+    fwrite(&nn.numberOfLayers, sizeof(int), 1, file);
+
+    for (int i = 0; i < nn.numberOfLayers; i++)
+    {
+        erzeugeMatrix(file, &nn.layers[i].weights);
+        erzeugeMatrix(file, &nn.layers[i].biases);
+    }
+
+    fclose(file);
 }
 
 void test_loadModelReturnsCorrectNumberOfLayers(void)