nn.c

#include "nn.h"

static float sigmoid(float a) {
    return (0.5*a) / (1 + fabs(a)) + 0.5;
}


void nn_process(nn *net) {
    float hidden1[NN_NUMHIDDEN];
    float hidden2[NN_NUMHIDDEN];
    int w = 0;
    int i, h, o;

    /* hidden layer 1 */
    for (h = 0; h < NN_NUMHIDDEN; h++) {
        float activation = 0;
        for (i = 0; i < NN_NUMINPUTS; i++)
            activation += net->weight[w++] * net->input[i];

        activation += net->weight[w++];
        hidden1[h] = sigmoid(activation);
    }

    /* hidden layer 2 */
    for (h = 0; h < NN_NUMHIDDEN; h++) {
        float activation = 0;
        for (i = 0; i < NN_NUMHIDDEN; i++)
            activation += net->weight[w++] * hidden1[i];

        activation += net->weight[w++];
        hidden2[h] = sigmoid(activation);
    }

    /* output layer */
    for (o = 0; o < NN_NUMOUTPUTS; o++) {
        float activation = 0;
        for (h = 0; h < NN_NUMHIDDEN; h++)
            activation += net->weight[w++] * hidden2[h];

        activation += net->weight[w++];
        net->output[o] = sigmoid(activation);
    }
}


void nn_fillrandom(nn *net) {
    int w;
    for (w = 0; w < NN_NUMWEIGHTS; w++)
        net->weight[w] = RANDDBL(-8.0, 8.0);
}

void nn_mutate(nn *net) {
    if (DICE(10)) {
        /* high mutation */
        int w;
        for (w = 0; w < NN_NUMWEIGHTS; w++)
            if (DICE(200)) net->weight[w] += RANDDBL(-8, 8);
    }

    else {
        int w;
        for (w = 0; w < NN_NUMWEIGHTS; w++) {
            if (DICE(500)) net->weight[w] += RANDDBL(-1, 1);
            if (DICE(2000)) net->weight[w] += RANDDBL(-8, 8);
        }
    }

    /* clamp */
    int w;
    for (w = 0; w < NN_NUMWEIGHTS; w++)
        net->weight[w] = RETMAX(-10, RETMIN(10, net->weight[w]));
}

void nn_copy(nn *dest, nn *src) {
    int w;
    for (w = 0; w < NN_NUMWEIGHTS; w++)
        dest->weight[w] = src->weight[w];
}

void nn_print(nn *net) {
    int i, h, o;
    int w = 0;
    for (h = 0; h < NN_NUMHIDDEN; h++) {
        for (i = 0; i < NN_NUMINPUTS; i++)
            printf("%2.2f ", net->weight[w++]);

        printf("%2.2f\n", net->weight[w++]);
    }

    printf("\n\n");

    for (o = 0; o < NN_NUMOUTPUTS; o++) {
        for (h = 0; h < NN_NUMHIDDEN; h++)
            printf("%2.2f ", net->weight[w++]);

        printf("%2.2f\n", net->weight[w++]);
    }

    printf("\n\n");
}