diff --git a/paddle/majel/dim.h b/paddle/majel/dim.h
index cf7682b6865ec01084f5e1b0bb97b8090f95dca3..ba718ce5b7686b1b0040c3a54d0895d773f208f5 100644
--- a/paddle/majel/dim.h
+++ b/paddle/majel/dim.h
@@ -4,14 +4,9 @@
 #include <sstream>
 #include <stdexcept>
 #include <type_traits>
-/*
-#ifdef __CUDACC__
-    #include <host_defines.h>
-#endif
-*/
 
-#include "hostdevice.h"
-#include "paddle/utils/Logging.h"
+#include "majel/hostdevice.h"
+#include "majel/util.h"
 
 namespace majel {
 
@@ -79,7 +74,7 @@ struct Dim<1> {
       throw std::invalid_argument("Index out of range.");
     }
 #else
-    CHECK(idx < size.head);
+    MAJEL_ASSERT(idx < size.head);
 #endif
   }
 
@@ -136,7 +131,7 @@ HOSTDEVICE int& indexer(Dim<D>& dim, int idx) {
     throw std::invalid_argument("Tried to access a negative dimension");
   }
 #else
-  CHECK(idx >= 0);
+  MAJEL_ASSERT(idx >= 0);
 #endif
   if (idx == 0) {
     return dim.head;
@@ -151,7 +146,7 @@ HOSTDEVICE int& indexer<1>(Dim<1>& dim, int idx) {
     throw std::invalid_argument("Invalid index");
   }
 #else
-  CHECK(idx == 0);
+  MAJEL_ASSERT(idx == 0);
 #endif
   return dim.head;
 }
@@ -163,7 +158,7 @@ HOSTDEVICE int indexer(const Dim<D>& dim, int idx) {
     throw std::invalid_argument("Tried to access a negative dimension");
   }
 #else
-  CHECK(idx >= 0);
+  MAJEL_ASSERT(idx >= 0);
 #endif
   if (idx == 0) {
     return dim.head;
@@ -178,7 +173,7 @@ HOSTDEVICE int indexer<1>(const Dim<1>& dim, int idx) {
     throw std::invalid_argument("Invalid index");
   }
 #else
-  CHECK(idx == 0);
+  MAJEL_ASSERT(idx == 0);
 #endif
   return dim.head;
 }
diff --git a/paddle/majel/test/dim_test.cu b/paddle/majel/test/dim_test.cu
index 380204531d846aaddfb4be140fce61913d7a8247..ed7c34ffd1da7dd27adb98da7823125a954bd972 100644
--- a/paddle/majel/test/dim_test.cu
+++ b/paddle/majel/test/dim_test.cu
@@ -1,7 +1,7 @@
 #include <thrust/device_vector.h>
 #include <sstream>
-#include "majel/dim.h"
 
+#include "majel/dim.h"
 #include "gtest/gtest.h"
 
 __global__ void test(majel::Dim<2>* o) {
@@ -16,22 +16,22 @@ __global__ void dyn_idx_gpu(int* o) {
 TEST(Dim, Equality) {
     // construct a Dim on the CPU
     auto a = majel::make_dim(3, 4);
-    EXPECT_EQ(get<0>(a), 3);
-    EXPECT_EQ(get<1>(a), 4);
+    EXPECT_EQ(majel::get<0>(a), 3);
+    EXPECT_EQ(majel::get<1>(a), 4);
 
     // construct a Dim on the GPU
     thrust::device_vector<majel::Dim<2>> t(2);
     test<<<1,1>>>(thrust::raw_pointer_cast(t.data()));
     a = t[0];
-    EXPECT_EQ(get<0>(a), 5);
-    EXPECT_EQ(get<1>(a), 6);
+    EXPECT_EQ(majel::get<0>(a), 5);
+    EXPECT_EQ(majel::get<1>(a), 6);
 
     // linearization
-    auto b = make_dim(7, 8);
-    EXPECT_EQ(linearize(a, b), 83);
+    auto b = majel::make_dim(7, 8);
+    EXPECT_EQ(majel::linearize(a, b), 83);
 
     // product
-    EXPECT_EQ(product(a), 30);
+    EXPECT_EQ(majel::product(a), 30);
 
     // mutate a Dim
     majel::get<1>(b) = 10;
@@ -53,7 +53,7 @@ TEST(Dim, Equality) {
     EXPECT_EQ(res, 6);
 
     // ex_prefix_mul
-    majel::Dim<3> c = majel::ex_prefix_mul(Dim<3>(3, 4, 5));
+    majel::Dim<3> c = majel::ex_prefix_mul(majel::Dim<3>(3, 4, 5));
     EXPECT_EQ(majel::get<0>(c), 1);
     EXPECT_EQ(majel::get<1>(c), 3);
     EXPECT_EQ(majel::get<2>(c), 12);
diff --git a/paddle/majel/util.h b/paddle/majel/util.h
new file mode 100644
index 0000000000000000000000000000000000000000..ab21e1869f793d07d4382596a3e6f50b5de7ead1
--- /dev/null
+++ b/paddle/majel/util.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#define STRINGIFY(x) #x
+#define TOSTRING(x) STRINGIFY(x)
+
+#if defined(__APPLE__) && defined(__CUDA_ARCH__) && !defined(NDEBUG)
+#include <stdio.h>
+#define MAJEL_ASSERT(e)                                                       \
+  do {                                                                        \
+    if (!(e)) {                                                               \
+      printf(                                                                 \
+          "%s:%d Assertion `%s` failed.\n", __FILE__, __LINE__, TOSTRING(e)); \
+      asm("trap;");                                                           \
+    }                                                                         \
+  } while (0)
+
+#define MAJEL_ASSERT_MSG(e, m)                      \
+  do {                                              \
+    if (!(e)) {                                     \
+      printf("%s:%d Assertion `%s` failed (%s).\n", \
+             __FILE__,                              \
+             __LINE__,                              \
+             TOSTRING(e),                           \
+             m);                                    \
+      asm("trap;");                                 \
+    }                                               \
+  } while (0)
+#else
+#include <assert.h>
+#define MAJEL_ASSERT(e) assert(e)
+#define MAJEL_ASSERT_MSG(e, m) assert((e) && (m))
+#endif
+
+namespace majel {
+namespace detail {
+
+inline int div_up(int x, int y) { return (x + y - 1) / y; }
+}
+}