Add custom type vector support

[geyyer]

• add vectorization support for custom types defined as non-native types or user-defined objects
• add a test to check if native and non-native vector types take same expected space in memory

[aosewski]

Good work! I'd add few more test cases and maybe reconsider some aliases naming.

[aosewski]

I'd check also for non-native-vector data alignment if it's really next_pow_of_2. Moreover I'd add also a test case for data type which is not just a thin wrapper around standard types, ie consider creating Complex data type with real & img members.

[geyyer]

Formally we have to create vectors taking next_pow_of_2 space in memory. In fact compiler optimizes these data structures and they take only space they actually need. We check memory footprint in the tests. Indeed, I'll try to add a complex type.

[geyyer]

Added in 678c398

[aosewski]

@geyyer As for checking the alignment I rather was thinking about using alignof or alignment_of expressions to test it, since we have custom alignment. I understand that the compiler may do some optimizations to that. But my reasoning is to make sure that in device memory those data types will have the alignment as expected. Otherwise we may have observe unexpected lower memory bandwidth due to not fulfilled memory read/write alignment requirement.

[aosewski]

I assume it would be sufficient to make a test case where you check alignment of vector holding different size of elements (ie of sizes we define aliases for: 2,4,8,16,32,64,128,256) of just single data type.

[aosewski]

You could also check here if all values were properly default initialized. They all should have value equal to the result of calling default constructor custom_bool_t() : data{type{}} {} . Similar for all other test cases.

[geyyer]

If I understand your idea correctly, that's exactly what we check in these tests: we create a std vector with some values (test_vec); assign values to a vector type (right_vec) element-wise; create another vector (left_vec) using the default constructor; compare the new vector (left_vec) with the reference vector (test_vec). This way we can check both default constructor and AsType method. Please let me know if I missed something!

[aosewski]

I meant that after this line vector_type<custom_bool_t, size> right_vec; all values of right_vec should have been default initialized - that is have a default value after calling default constructor - (usually zero for numeric types, boolean is false). Since we have vector of values, then I'd expect that all elements after this line have default value.

[aosewski]

One more note - you're checking AsType for just single vector element type. Please add test case where you call AsType for all vector type access combination/views.

[geyyer]

Added vector reshaping tests in dc7208c

[aosewski]

I meant that after this line vector_type<custom_bool_t, size> right_vec; all values of right_vec should have been default initialized - that is have a default value after calling default constructor - (usually zero for numeric types, boolean is false). Since we have vector of values, then I'd expect that all elements after this line have default value.

[aosewski]

Why you don't add here alignment of this union like in previous smaller vector types? alignas(next_pow2....

[geyyer]

Good catch, fixed in d08a8c5