Merge pull request #128 from Smit-create/math2

Add more math functions

Author: certik

integration_tests/test_math.py

@@ -1,8 +1,44 @@
-from math import factorial
+from math import factorial, isqrt, perm, comb, degrees, radians
+from ltypes import i32, f64
 
 def test_factorial_1():
     i: i32
     i = factorial(10)
     print(i)
 
+
+def test_comb():
+    i: i32
+    i = comb(10, 2)
+    print(i)
+
+
+def test_perm():
+    i: i32
+    i = perm(5, 2)
+
+
+def test_isqrt():
+    i: i32
+    i = isqrt(15)
+    print(i)
+
+
+def test_degrees():
+    i: f64
+    i = degrees(32.2)
+    print(i)
+
+
+def test_radians():
+    i: f64
+    i = degrees(100.1)
+    print(i)
+
+
 test_factorial_1()
+test_comb()
+test_isqrt()
+test_perm()
+test_degrees()
+test_radians()

src/runtime/math.py

@@ -1,3 +1,8 @@
+from ltypes import i32, f64
+
+def pi() -> f64:
+    return 3.141592653589793238462643383279502884197
+
 def factorial(x: i32) -> i32:
     """
     Computes the factorial of `x`.
@@ -7,7 +12,63 @@ def factorial(x: i32) -> i32:
         return 0
     result: i32
     result = 1
-    while x > 0:
-        result = result * x
-        x -= 1
+    i: i32
+    for i in range(1, x+1):
+        result *= i
     return result
+
+
+def comb(n: i32, k: i32) -> i32:
+    """
+    Computes the result of `nCk`, i.e, the number of ways to choose `k`
+    items from `n` items without repetition and without order.
+    """
+
+    if n < k or n < 0:
+        return 0
+    return factorial(n)//(factorial(k)*factorial(n-k))
+
+
+def perm(n: i32, k: i32) -> i32:
+    """
+    Computes the result of `nPk`, i.e, the number of ways to choose `k` items
+    from `n` items without repetition and with order.
+    """
+
+    if n < k or n < 0:
+        return 0
+    return factorial(n)//factorial(n-k)
+
+
+def isqrt(n: i32) -> i32:
+    """
+    Computes the integer square root of the nonnegative integer `n`.
+    """
+    if n < 0:
+        raise ValueError('`n` should be nonnegative')
+    low: i32
+    mid: i32
+    high: i32
+    low = 0
+    high = n+1
+    while low + 1 < high:
+        mid = (low + high)//2
+        if mid*mid <= n:
+            low = mid
+        else:
+            high = mid
+    return low
+
+
+def degrees(x: f64) -> f64:
+    """
+    Convert angle `x` from radians to degrees.
+    """
+    return x * 180.0 / pi()
+
+
+def radians(x: f64) -> f64:
+    """
+    Convert angle `x` from degrees to radians.
+    """
+    return x * pi() / 180.0