C library

The C interface introduces two array concepts:

  • A base array that has a rank (number of dimensions) and shape (array of dimension sizes). The memory of the base array is always a single contiguous block of memory.
  • A view array that, beside a rank and a shape, has a start (start offset in number of elements) and a stride (array of dimension strides in number of elements). The view array refers to a (sub)set of a underlying base array where start is the offset into the base array and stride is number of elements to skip in order to iterate one step in a given dimension.

API

The C interface consists of a broad range of functions – in the following, we describe some of the important ones.

Create a new empty array with rank number of dimensions and with the shape shape and returns a handler/pointer to a complete view of this new array:

bh_multi_array_{TYPE}_p bh_multi_array_{TYPE}_new_empty(uint64_t rank, const int64_t* shape);

Get pointer/handle to the base of a view:

bh_base_p bh_multi_array_{TYPE}_get_base(const bh_multi_array_{TYPE}_p self);

Destroy the base array and the associated memory:

void bh_multi_array_{TYPE}_destroy_base(bh_base_p base);

Destroy the view and base array (but not the associated memory):

void bh_multi_array_{TYPE}_free(const bh_multi_array_{TYPE}_p self);

Some meta-data access functions:

// Gets the number of elements in the array
uint64_t bh_multi_array_{TYPE}_get_length(bh_multi_array_{TYPE}_p self);

// Gets the number of dimensions in the array
uint64_t bh_multi_array_{TYPE}_get_rank(bh_multi_array_{TYPE}_p self);

// Gets the number of elements in the dimension
uint64_t bh_multi_array_{TYPE}_get_dimension_size(bh_multi_array_{TYPE}_p self, const int64_t dimension);

Before accesses the memory of an array, one has to synchronize the array:

void bh_multi_array_{TYPE}_sync(const bh_multi_array_{TYPE}_p self);

Access the memory of an array (remember to synchronize):

bh_{TYPE}* bh_multi_array_{TYPE}_get_base_data(bh_base_p base);

Some of the element-wise operations:

//Addition
void bh_multi_array_{TYPE}_add(bh_multi_array_{TYPE}_p out, const bh_multi_array_{TYPE}_p lhs, const bh_multi_array_{TYPE}_p rhs);

//Multiply
void bh_multi_array_{TYPE}_multiply(bh_multi_array_{TYPE}_p out, const bh_multi_array_{TYPE}_p lhs, const bh_multi_array_{TYPE}_p rhs);

//Addition: scalar + array
void bh_multi_array_{TYPE}_add_scalar_lhs(bh_multi_array_{TYPE}_p out, bh_{TYPE} lhs, const bh_multi_array_{TYPE}_p rhs);

Some of the reduction and accumulate (aka scan) functions where axis is the dimension to reduce/accumulate over:

//Sum
void bh_multi_array_{TYPE}_add_reduce(bh_multi_array_{TYPE}_p out, const bh_multi_array_{TYPE}_p in, bh_int64 axis);

//Prefix sum
void bh_multi_array_{TYPE}_add_accumulate(bh_multi_array_{TYPE}_p out, const bh_multi_array_{TYPE}_p in, bh_int64 axis);