Changed random function to use a better generator

Signed-off-by: Koren-Brand <[email protected]>

icicle/include/icicle/fields/field.h

@@ -689,11 +689,18 @@ class Field
     return rv;
   }
 
+  inline static std::mt19937 field_rand_generator = std::mt19937{};
+
+  static void seed_rand_generator(unsigned seed) { field_rand_generator.seed(seed); }
+
+  // NOTE this function is used for test and examples - it assumed it is executed on a single-thread (no two threads 
+  // accessing field_rand_generator at the same time)
   static HOST_INLINE Field rand_host()
   {
+    std::uniform_int_distribution<unsigned> distribution;
     Field value{};
     for (unsigned i = 0; i < TLC; i++)
-      value.limbs_storage.limbs[i] = rand();
+      value.limbs_storage.limbs[i] = distribution(field_rand_generator);
     while (lt(Field{get_modulus()}, value))
       value = value - Field{get_modulus()};
     return value;

icicle/tests/test_base.h

@@ -6,6 +6,9 @@
 #include "icicle/runtime.h"
 #include "icicle/utils/log.h"
 
+#include "icicle/fields/field_config.h"
+using namespace field_config; // To have access to the Field rand-gen
+
 using FpMiliseconds = std::chrono::duration<float, std::chrono::milliseconds::period>;
 #define START_TIMER(timer) auto timer##_start = std::chrono::high_resolution_clock::now();
 #define END_TIMER(timer, msg, enable)                                                                                  \
@@ -22,14 +25,15 @@ class IcicleTestBase : public ::testing::Test
 {
 public:
   static inline std::vector<std::string> s_registered_devices;
-  static inline std::string s_main_device = UNKOWN_DEVICE;
+  static inline std::string s_main_device = "CPU";
   static inline std::string s_ref_device = "CPU"; // assuming always present
   // SetUpTestSuite/TearDownTestSuite are called once for the entire test suite
   static void SetUpTestSuite()
   {
-    auto seed = time(NULL);
+    unsigned seed = time(NULL);
     srand(seed);
     ICICLE_LOG_INFO << "Seed for tests is: " << seed;
+    scalar_t::seed_rand_generator(seed);
 #ifdef BACKEND_BUILD_DIR
     setenv("ICICLE_BACKEND_INSTALL_DIR", BACKEND_BUILD_DIR, 0 /*=replace*/);
 #endif