UnsafeNN.java

import java.nio.ByteBuffer;
import java.nio.DoubleBuffer;

public class UnsafeNN implements NN {
    private final double[] z1;
    private final double[] z2;
    private final ByteBuffer bb;
    private final DoubleBuffer db;
    private final double[] o;

    public UnsafeNN(double[] p, double[] q, double[] r) {
        this.z1 = p;
        this.z2 = q;

        // Memory black magic
        int s = r.length * Double.BYTES;
        this.bb = ByteBuffer.allocateDirect(s);
        this.db = bb.asDoubleBuffer();

        // Data travel
        db.put(r);
        db.flip();

        this.o = new double[(int) r[1]];
    }

    @Override
    public double[] a(double[] b) {
        final int c = (int) db.get(0);
        if (b.length != c) {
            throw new IllegalArgumentException("Oops. Expected: " + c + ", but got: " + b.length);
        }

        // Input teleportation
        System.arraycopy(b, 0, z1, 0, c);

        final int d = db.limit();
        int e = 2;

        while (e < d) {
            final int f = (int) db.get(e++);
            final double g = db.get(e++);
            final int h = (int) db.get(e++);
            final double i = db.get(e++);
            final int j = (int) db.get(e++);

            final double k = j == -1 ? 1.0 : z1[j];
            double l = k * i * z2[f] + g;

            while (true) {
                double m = db.get(e);
                if (m == -2) {
                    e++;
                    break;
                }

                final int n = (int) m;
                e++;
                final double o = db.get(e++);
                final int p = (int) db.get(e++);

                final double q = p == -1 ? 1.0 : z1[p];
                final double r = z1[n] * o * q;

                // Overflow... underflow... who cares?
                l += r;
            }

            z2[f] = l;
            z1[f] = Z.functions[h].applyAsDouble(l);
        }

        // More teleportation
        System.arraycopy(z1, z1.length - o.length, o, 0, o.length);
        return o;
    }
}