a smol nn lib written in C w/ a scalar valued autograd engine

include the header file from src/NN.h and you're set (⌐■_■)

What you got bro?

• Reverse-mode automatic differentiation over a dynamically built DAG.
• DAG operates over scalar values
• Scalar values implemented via Value

typedef struct Value {
  double val; // double value
  struct Value** children; // array of pointers to child values
  double* local_grads; // accompanying local grads
  int n_children;
} Value;

• Scalar Ops on Two Values (add, mul, sub, sigmoid, etc.)
• Tensor/Matrix/Vector Ops (coming soon)
• Wrappers for NN stuff (coming soon)

TODO:
🟡 = in progress, 🟢 = done

• 🟢 write tests for scalar ops
• 🟡 implement backprop
• implement tensor ops