OpenCL RNG

Unfortunately most OpenCL implementations don't support C++

pystencils/include/philox_rand.h

-#include <cstdint>
-
+#ifndef __OPENCL_VERSION__
 #if defined(__SSE2__) || defined(_MSC_VER)
 #include <emmintrin.h> // SSE2
 #endif
@@ -33,12 +32,15 @@
 #ifdef __riscv_v
 #include <riscv_vector.h>
 #endif
+#endif
 
-#ifndef __CUDA_ARCH__
+#ifdef __CUDA_ARCH__
+#define QUALIFIERS static __forceinline__ __device__
+#elif defined(__OPENCL_VERSION__)
+#define QUALIFIERS static inline
+#else
 #define QUALIFIERS inline
 #include "myintrin.h"
-#else
-#define QUALIFIERS static __forceinline__ __device__
 #endif
 
 #define PHILOX_W32_0   (0x9E3779B9)
@@ -48,8 +50,15 @@
 #define TWOPOW53_INV_DOUBLE (1.1102230246251565e-16)
 #define TWOPOW32_INV_FLOAT (2.3283064e-10f)
 
+#ifdef __OPENCL_VERSION__
+#include "opencl_stdint.h"
+typedef uint32_t uint32;
+typedef uint64_t uint64;
+#else
+#include <cstdint>
 typedef std::uint32_t uint32;
 typedef std::uint64_t uint64;
+#endif
 
 #if defined(__ARM_FEATURE_SVE) && defined(__ARM_FEATURE_SVE_BITS) && __ARM_FEATURE_SVE_BITS > 0
 typedef svfloat32_t svfloat32_st __attribute__((arm_sve_vector_bits(__ARM_FEATURE_SVE_BITS)));
@@ -67,6 +76,9 @@ QUALIFIERS uint32 mulhilo32(uint32 a, uint32 b, uint32* hip)
 #if defined(__powerpc__) && (!defined(__clang__) || defined(__xlC__))
     *hip = __mulhwu(a,b);
     return a*b;
+#elif defined(__OPENCL_VERSION__)
+    *hip = mul_hi(a,b);
+    return a*b;
 #else
     uint64 product = ((uint64)a) * ((uint64)b);
     *hip = product >> 32;
@@ -106,7 +118,12 @@ QUALIFIERS double _uniform_double_hq(uint32 x, uint32 y)
 
 
 QUALIFIERS void philox_double2(uint32 ctr0, uint32 ctr1, uint32 ctr2, uint32 ctr3,
-                               uint32 key0, uint32 key1, double & rnd1, double & rnd2)
+                               uint32 key0, uint32 key1,
+#ifdef __OPENCL_VERSION__
+                               double * rnd1, double * rnd2)
+#else
+                               double & rnd1, double & rnd2)
+#endif
 {
     uint32 key[2] = {key0, key1};
     uint32 ctr[4] = {ctr0, ctr1, ctr2, ctr3};
@@ -121,14 +138,23 @@ QUALIFIERS void philox_double2(uint32 ctr0, uint32 ctr1, uint32 ctr2, uint32 ctr
     _philox4x32bumpkey(key); _philox4x32round(ctr, key);  // 9
     _philox4x32bumpkey(key); _philox4x32round(ctr, key);  // 10
 
+#ifdef __OPENCL_VERSION__
+    *rnd1 = _uniform_double_hq(ctr[0], ctr[1]);
+    *rnd2 = _uniform_double_hq(ctr[2], ctr[3]);
+#else
     rnd1 = _uniform_double_hq(ctr[0], ctr[1]);
     rnd2 = _uniform_double_hq(ctr[2], ctr[3]);
+#endif
 }
 
 
 QUALIFIERS void philox_float4(uint32 ctr0, uint32 ctr1, uint32 ctr2, uint32 ctr3,
                               uint32 key0, uint32 key1,
+#ifdef __OPENCL_VERSION__
+                              float * rnd1, float * rnd2, float * rnd3, float * rnd4)
+#else
                               float & rnd1, float & rnd2, float & rnd3, float & rnd4)
+#endif
 {
     uint32 key[2] = {key0, key1};
     uint32 ctr[4] = {ctr0, ctr1, ctr2, ctr3};
@@ -143,13 +169,20 @@ QUALIFIERS void philox_float4(uint32 ctr0, uint32 ctr1, uint32 ctr2, uint32 ctr3
     _philox4x32bumpkey(key); _philox4x32round(ctr, key);  // 9
     _philox4x32bumpkey(key); _philox4x32round(ctr, key);  // 10
 
+#ifdef __OPENCL_VERSION__
+    *rnd1 = ctr[0] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
+    *rnd2 = ctr[1] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
+    *rnd3 = ctr[2] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
+    *rnd4 = ctr[3] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
+#else
     rnd1 = ctr[0] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
     rnd2 = ctr[1] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
     rnd3 = ctr[2] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
     rnd4 = ctr[3] * TWOPOW32_INV_FLOAT + (TWOPOW32_INV_FLOAT/2.0f);
+#endif
 }
 
-#ifndef __CUDA_ARCH__
+#if !defined(__CUDA_ARCH__) && !defined(__OPENCL_VERSION__)
 #if defined(__SSE4_1__) || defined(_MSC_VER)
 QUALIFIERS void _philox4x32round(__m128i* ctr, __m128i* key)
 {

pystencils/rng.py

@@ -53,8 +53,9 @@ class RNGBase(CustomCodeNode):
             else:
                 code += f"{vector_instruction_set[r.dtype.base_name] if vector_instruction_set else r.dtype} " + \
                         f"{r.name};\n"
-        code += (self._name + "(" + ", ".join([print_arg(a) for a in self.args]
-                                              + [r.name for r in self.result_symbols]) + ");\n")
+        args = [print_arg(a) for a in self.args] + \
+               [('&' if dialect == 'opencl' else '') + r.name for r in self.result_symbols]
+        code += (self._name + "(" + ", ".join(args) + ");\n")
         return code
 
     def __repr__(self):

pystencils_tests/test_random.py

@@ -21,12 +21,16 @@ if get_compiler_config()['os'] == 'windows':
         instruction_sets.remove('avx512')
 
 
-@pytest.mark.parametrize('target,rng', (('cpu', 'philox'), ('cpu', 'aesni'), ('gpu', 'philox')))
+@pytest.mark.parametrize('target,rng', (('cpu', 'philox'), ('cpu', 'aesni'), ('gpu', 'philox'), ('opencl', 'philox')))
 @pytest.mark.parametrize('precision', ('float', 'double'))
 @pytest.mark.parametrize('dtype', ('float', 'double'))
 def test_rng(target, rng, precision, dtype, t=124, offsets=(0, 0), keys=(0, 0), offset_values=None):
     if target == 'gpu':
         pytest.importorskip('pycuda')
+    if target == 'opencl':
+        pytest.importorskip('pyopencl')
+        from pystencils.opencl.opencljit import init_globally
+        init_globally()
     if instruction_sets and set(['neon', 'sve', 'vsx', 'rvv']).intersection(instruction_sets) and rng == 'aesni':
         pytest.xfail('AES not yet implemented for this architecture')
     if rng == 'aesni' and len(keys) == 2: