>> error fixed + test with a python impl

.github/workflows/CI.yml

@@ -4,7 +4,7 @@
 #    maturin generate-ci github
 #
 name: CI
-
+# unexist rn
 on:
   push:
     branches:

fib.py

@@ -0,0 +1,20 @@
+def fast2(n: int) -> int:
+    "port to python"
+    a, b = 0, 1
+    bit_len = n.bit_length()
+    mask = 0 if bit_len == 0 else 1 << (bit_len - 1)
+    while mask > 0:
+        c = a * (2 * b - a)
+        d = a * a + b * b
+        if n & mask == 0:
+            a, b = c, d
+        else:
+            a, b = d, c + d
+        mask >>= 1
+    return a
+
+
+
+
+
+

fibtest.py

@@ -0,0 +1,11 @@
+import timeit
+import fib
+import lda_module
+import random
+
+f = {"randint": random.randint}
+g = "92"
+# g = "randint(0, 92)"
+print(g)
+print(timeit.timeit(f"fast2({g})", globals=f | {"fast2": fib.fast2}))  # 0.69
+print(timeit.timeit(f"fib({g})", globals=f | {"fib": lda_module.fib}))  # 0.31

src/fib.rs

@@ -5,20 +5,19 @@
 pub fn fast2(n: u64) -> u64 {
     let (mut a, mut b) = (0, 1);
     let m = n;
-    let mut mask = (u64::MAX >> (m.leading_zeros() + 1)) + 1;
+    let bit_len = u64::BITS - m.leading_zeros(); // copilot 
+    let mut mask = if bit_len == 0 { 0 } else { 1 << (bit_len - 1) };
     while mask > 0 {
         let c = a * (2 * b - a);
         let d = a * a + b * b;
         if m & mask == 0 {
             (a, b) = (c, d);
-        }
-        else {
+        } else {
             (a, b) = (d, c + d);
         }
         mask >>= 1;
     }
     a
-
 }
 // 0, 1, 3, 7
 // -> -1 /2 -1 /2 -1 /2

src/lib.rs

@@ -5,6 +5,7 @@ pub mod pyexport {
 
     /// this shit is the thing now in python
     #[pyfunction]
+    #[pyo3(signature = (n), text_signature = "(n: int) -> int")]
     fn fib(n: u64) -> u64 {
         crate::fib::fast2(n)
         // currently use u64 as a large number tupe, can use num_bigint