Merge pull request lcompilers#2318 from OmarMesqq/feat/improve-random…

…-seed-entropy

Implement random.seed()

integration_tests/test_random.py

@@ -52,6 +52,33 @@ def test_weibullvariate():
     r = random.weibullvariate(-5.6, 1.2)
     print(r)
 
+def test_seed():
+    random.seed()
+    t6: f64 = random.random()
+    random.seed(123)
+    t1: f64
+    t1 = random.random()
+    random.seed(321)
+    t2: f64
+    t2 = random.random()
+    random.seed(123)
+    t3: f64
+    t3 = random.random()
+    random.seed(0)
+    t4: f64
+    t4 = random.random()
+    random.seed(0)
+    t5: f64
+    t5 = random.random()
+    random.seed()
+    t7: f64 = random.random()
+    assert t1 != t2
+    assert t1 == t3
+    assert t1 != t4
+    assert t1 != t5
+    assert t4 == t5
+    assert t6 != t7
+
 def check():
     test_random()
     test_randrange()
@@ -60,5 +87,6 @@ def check():
     test_paretovariate()
     test_expovariate()
     test_weibullvariate()
+    test_seed()
 
 check()

src/libasr/runtime/lfortran_intrinsics.c

@@ -96,6 +96,16 @@ LFORTRAN_API void _lfortran_random_number(int n, double *v)
     }
 }
 
+LFORTRAN_API void _lfortran_init_random_seed(unsigned seed)
+{
+    srand(seed);
+}
+
+LFORTRAN_API void _lfortran_init_random_clock()
+{
+    srand((unsigned int)clock());
+}
+
 LFORTRAN_API double _lfortran_random()
 {
     return (rand() / (double) RAND_MAX);

src/libasr/runtime/lfortran_intrinsics.h

@@ -67,6 +67,8 @@ typedef double _Complex double_complex_t;
 
 LFORTRAN_API double _lfortran_sum(int n, double *v);
 LFORTRAN_API void _lfortran_random_number(int n, double *v);
+LFORTRAN_API void _lfortran_init_random_clock();
+LFORTRAN_API void _lfortran_init_random_seed(unsigned seed);
 LFORTRAN_API double _lfortran_random();
 LFORTRAN_API int _lfortran_randrange(int lower, int upper);
 LFORTRAN_API int _lfortran_random_int(int lower, int upper);

src/runtime/random.py

@@ -32,6 +32,30 @@ def random() -> f64:
 def _lfortran_random() -> f64:
     pass
 
+@overload
+def seed() -> None:
+    """
+    Initializes the random number generator.
+    """
+    _lfortran_init_random_clock()
+    return
+
+@overload
+def seed(seed: i32) -> None:
+    """
+    Initializes the random number generator.
+    """
+    _lfortran_init_random_seed(seed)
+    return
+
+@ccall
+def _lfortran_init_random_clock() -> None:
+    pass
+
+@ccall
+def _lfortran_init_random_seed(seed: i32) -> None:
+    pass
+
 def randrange(lower: i32, upper: i32) -> i32:
     """
     Return a random integer N such that `lower <= N < upper`.