chore: move existing Value to forward module

src/forward/mod.rs

@@ -0,0 +1 @@
+pub mod value;

src/main.rs

@@ -1,11 +1,11 @@
 mod backprop;
-mod value;
+mod forward;
 
-use value::Value;
+use forward::value as fwd;
 
-fn f(x: Value) -> Value {
-    let a = Value::passive(3.0); // Passive variable
-    let b = Value::passive(2.0); // Passive variable
+fn f(x: fwd::Value) -> fwd::Value {
+    let a = fwd::Value::passive(3.0); // Passive variable
+    let b = fwd::Value::passive(2.0); // Passive variable
 
     // purely copying
     a * x * x + b / x
@@ -20,14 +20,14 @@ fn univariate_example() {
      * dfdx(x = 2.0) = 11.5
      */
 
-    let x = Value::new(2.0, 1.0); // Active variable
+    let x = fwd::Value::new(2.0, 1.0); // Active variable
     let y = f(x);
 
     assert_eq!(y.value, 13.0);
     assert_eq!(y.der, 11.5);
 }
 
-fn g(x1: Value, x2: Value) -> Value {
+fn g(x1: fwd::Value, x2: fwd::Value) -> fwd::Value {
     return x1 * x2;
 }
 
@@ -45,7 +45,7 @@ fn multivariate_example() {
      *
      * Note that this could be extended to R^n.
      */
-    let mut x = vec![Value::new(2.0, 0.0), Value::new(3.0, 0.0)]; // vector of arguments i.e. x = (x1, x2)
+    let mut x = vec![fwd::Value::new(2.0, 0.0), fwd::Value::new(3.0, 0.0)]; // vector of arguments i.e. x = (x1, x2)
     let mut grad_g = vec![0.0; 2];
     for i in 0..2 {
         x[i].der = 1.0; // seed the desired partial