starpu-max/doc/doxygen/chapters/api/data_interfaces.doxy

/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2010-2017                                CNRS
 * Copyright (C) 2011-2014,2017                           Inria
 * Copyright (C) 2009-2011,2014-2017                      Université de Bordeaux
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

/*! \defgroup API_Data_Interfaces Data Interfaces

\struct starpu_data_interface_ops
\ingroup API_Data_Interfaces
Per-interface data transfer methods.
\var void (*starpu_data_interface_ops::register_data_handle)(starpu_data_handle_t handle, unsigned home_node, void *data_interface)
    Register an existing interface into a data handle.

    This iterates over all memory nodes to initialize all fields of the data
    interface on each of them. Since data is not allocated yet except on the
    home node, pointers should be left as NULL except on the \p home_node, for
    which the pointers should be copied from the given \p data_interface, which
    was filled with the application's pointers.

\var starpu_ssize_t (*starpu_data_interface_ops::allocate_data_on_node)(void *data_interface, unsigned node)
    Allocate data for the interface on a given node. This should use
    starpu_malloc_on_node to perform the allocation(s), and fill the pointers
    in the data interface. It should return the size of the allocated memory, or
    -ENOMEM if memory could not be allocated.

\var void (*starpu_data_interface_ops::free_data_on_node)(void *data_interface, unsigned node)
    Free data of the interface on a given node.

\var const struct starpu_data_copy_methods *starpu_data_interface_ops::copy_methods
    This provides a series of methods for performing ram/cuda/opencl synchronous and asynchronous transfers.

\var void *(*starpu_data_interface_ops::handle_to_pointer)(starpu_data_handle_t handle, unsigned node)
    Return the current pointer (if any) for the handle on the given node.

\var size_t (*starpu_data_interface_ops::get_size)(starpu_data_handle_t handle)
    Return an estimation of the size of data, for performance models.

\var uint32_t (*starpu_data_interface_ops::footprint)(starpu_data_handle_t handle)
    Return a 32bit footprint which characterizes the data size and layout (nx, ny, ld, elemsize, etc.)

\var int (*starpu_data_interface_ops::compare)(void *data_interface_a, void *data_interface_b)
    Compare the data size and layout of two interfaces (nx, ny, ld, elemsize,
    etc.). It should return 1 if the two interfaces size and layout match, and 0
    otherwise.

\var void (*starpu_data_interface_ops::display)(starpu_data_handle_t handle, FILE *f)
    Dump the sizes of a handle to a file.

\var starpu_ssize_t (*starpu_data_interface_ops::describe)(void *data_interface, char *buf, size_t size)
    Describe the data into a string in a brief way, such as one letter to describe the type of data, and the data dimensions.

\var enum starpu_data_interface_id starpu_data_interface_ops::interfaceid
    An identifier that is unique to each interface.

\var char *starpu_data_interface_ops::name
    Name of the interface

\var size_t starpu_data_interface_ops::interface_size
    The size of the interface data descriptor.

\var char starpu_data_interface_ops::is_multiformat
    todo

\var char starpu_data_interface_ops::dontcache
    If set to non-zero, StarPU will never try to reuse an allocated
    buffer for a  different handle. This can be notably useful for
    application-defined interfaces which have a dynamic size, and for
    which it thus does not make sense to reuse the buffer since will
    probably not have the proper size.

\var struct starpu_multiformat_data_interface_ops* (*starpu_data_interface_ops::get_mf_ops)(void *data_interface)
    todo

\var int (*starpu_data_interface_ops::pack_data)(starpu_data_handle_t handle, unsigned node, void **ptr, starpu_ssize_t *count)
    Pack the data handle into a contiguous buffer at the address
    allocated with <c>starpu_malloc_flags(ptr, size, 0)</c> (and thus
    returned in \p ptr) and set the size of the newly created buffer
    in \p count. If \p ptr is <c>NULL</c>, the function should not
    copy the data in the buffer but just set count to the size of the
    buffer which would have been allocated. The special value -1
    indicates the size is yet unknown.

\var int (*starpu_data_interface_ops::unpack_data) (starpu_data_handle_t handle, unsigned node, void *ptr, size_t count)
    Unpack the data handle from the contiguous buffer at the address
    \p ptr of size \p count

\struct starpu_data_copy_methods
\ingroup API_Data_Interfaces
Defines the per-interface methods. If the
starpu_data_copy_methods::any_to_any method is provided, it will be
used by default if no specific method is provided. It can still be
useful to provide more specific method in case of e.g. available
particular CUDA or OpenCL support.
\var int (*starpu_data_copy_methods::can_copy)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, unsigned handling_node)
    If defined, allows the interface to declare whether it supports
    transferring from \p src_interface on node \p src_node to \p
    dst_interface on node \p dst_node, run from node \p handling_node.
    If not defined, it is assumed that the interface supports all
    transfers.

\var int (*starpu_data_copy_methods::ram_to_ram)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node CPU node. Return 0 on success.

\var int (*starpu_data_copy_methods::ram_to_cuda)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node CUDA node. Return 0 on success.

\var int (*starpu_data_copy_methods::ram_to_opencl)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node OpenCL node. Return 0 on success.

\var int (*starpu_data_copy_methods::ram_to_mic)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node MIC node. Return 0 on success.

\var int (*starpu_data_copy_methods::cuda_to_ram)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CUDA node to the \p dst_interface interface on the \p
    dst_node CPU node. Return 0 on success.

\var int (*starpu_data_copy_methods::cuda_to_cuda)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CUDA node to the \p dst_interface interface on the \p
    dst_node CUDA node. Return 0 on success.

\var int (*starpu_data_copy_methods::cuda_to_opencl)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CUDA node to the \p dst_interface interface on the \p
    dst_node OpenCL node. Return 0 on success.

\var int (*starpu_data_copy_methods::opencl_to_ram)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node OpenCL node to the \p dst_interface interface on the
    \p dst_node CPU node. Return 0 on success.

\var int (*starpu_data_copy_methods::opencl_to_cuda)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node OpenCL node to the \p dst_interface interface on the
    \p dst_node CUDA node. Return 0 on success.

\var int (*starpu_data_copy_methods::opencl_to_opencl)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node OpenCL node to the \p dst_interface interface on the
    \p dst_node OpenCL node. Return 0 on success.

\var int (*starpu_data_copy_methods::mic_to_ram)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MIC node to the \p dst_interface interface on the \p
    dst_node CPU node. Return 0 on success.

\var int (*starpu_data_copy_methods::scc_src_to_sink)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node node to the \p dst_interface interface on the \p
    dst_node node. Must return 0 if the transfer was actually
    completed completely synchronously, or <c>-EAGAIN</c> if at least
    some transfers are still ongoing and should be awaited for by the
    core.

\var int (*starpu_data_copy_methods::scc_sink_to_src)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node node to the \p dst_interface interface on the \p
    dst_node node. Must return 0 if the transfer was actually
    completed completely synchronously, or <c>-EAGAIN</c> if at least
    some transfers are still ongoing and should be awaited for by the core.

\var int (*starpu_data_copy_methods::scc_sink_to_sink)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node node to the \p dst_interface interface on the \p
    dst_node node. Must return 0 if the transfer was actually
    completed completely synchronously, or <c>-EAGAIN</c> if at least
    some transfers are still ongoing and should be awaited for by the
    core.

\var int (*starpu_data_copy_methods::ram_to_mpi_ms)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node MPI Slave node. Return 0 on success.

\var int (*starpu_data_copy_methods::mpi_ms_to_ram)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MPI Slave node to the \p dst_interface interface on
    the \p dst_node CPU node. Return 0 on success.

\var int (*starpu_data_copy_methods::mpi_ms_to_mpi_ms)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MPI Slave node to the \p dst_interface interface on
    the \p dst_node MPI Slave node. Return 0 on success.

\var int (*starpu_data_copy_methods::ram_to_cuda_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cudaStream_t stream)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node CUDA node, using the given stream. Must return 0 if the
    transfer was actually completed completely synchronously, or
    <c>-EAGAIN</c> if at least some transfers are still ongoing and
    should be awaited for by the core.

\var int (*starpu_data_copy_methods::cuda_to_ram_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cudaStream_t stream)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CUDA node to the \p dst_interface interface on the \p
    dst_node CPU node, using the given stream. Must return 0 if the
    transfer was actually completed completely synchronously, or
    <c>-EAGAIN</c> if at least some transfers are still ongoing and
    should be awaited for by the core.

\var int (*starpu_data_copy_methods::cuda_to_cuda_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cudaStream_t stream)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CUDA node to the \p dst_interface interface on the \p
    dst_node CUDA node, using the given stream. Must return 0 if the
    transfer was actually completed completely synchronously, or
    <c>-EAGAIN</c> if at least some transfers are still ongoing and
    should be awaited for by the core.

\var int (*starpu_data_copy_methods::ram_to_opencl_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node OpenCL node, by recording in \p event, a pointer to a
    <c>cl_event</c>, the event of the last submitted transfer. Must
    return 0 if the transfer was actually completed completely
    synchronously, or <c>-EAGAIN</c> if at least some transfers are
    still ongoing and should be awaited for by the core.

\var int (*starpu_data_copy_methods::opencl_to_ram_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node OpenCL node to the \p dst_interface interface on the
    \p dst_node CPU node, by recording in \p event, a pointer to a
    <c>cl_event</c>, the event of the last submitted transfer. Must
    return 0 if the transfer was actually completed completely
    synchronously, or <c>-EAGAIN</c> if at least some transfers are
    still ongoing and should be awaited for by the core.

\var int (*starpu_data_copy_methods::opencl_to_opencl_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node OpenCL node to the \p dst_interface interface on the
    \p dst_node OpenCL node, by recording in \p event, a pointer to a
    <c>cl_event</c>, the event of the last submitted transfer. Must
    return 0 if the transfer was actually completed completely
    synchronously, or <c>-EAGAIN</c> if at least some transfers are
    still ongoing and should be awaited for by the core.

\var int (*starpu_data_copy_methods::ram_to_mpi_ms_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void * event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node MPI Slave node, with the given even. Must return 0 if the
    transfer was actually completed completely synchronously, or
    <c>-EAGAIN</c> if at least some transfers are still ongoing and
    should be awaited for by the core.

\var int (*starpu_data_copy_methods::mpi_ms_to_ram_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void * event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MPI Slave node to the \p dst_interface interface on
    the \p dst_node CPU node, with the given event. Must return 0 if
    the transfer was actually completed completely synchronously, or
    <c>-EAGAIN</c> if at least some transfers are still ongoing and
    should be awaited for by the core.

\var int (*starpu_data_copy_methods::mpi_ms_to_mpi_ms_async)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void * event)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MPI Slave node to the \p dst_interface interface on
    the \p dst_node MPI Slave node, using the given stream. Must
    return 0 if the transfer was actually completed completely
    synchronously, or <c>-EAGAIN</c> if at least some transfers are
    still ongoing and should be awaited for by the core.

\var int (*starpu_data_copy_methods::ram_to_mic_async)(void *src_intreface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node CPU node to the \p dst_interface interface on the \p
    dst_node MIC node. Must return 0 if the transfer was actually
    completed completely synchronously, or <c>-EAGAIN</c> if at least
    some transfers are still ongoing and should be awaited for by the
    core.

\var int (*starpu_data_copy_methods::mic_to_ram_async)(void *src_intreface, unsigned src_node, void *dst_interface, unsigned dst_node)
    Define how to copy data from the \p src_interface interface on the
    \p src_node MIC node to the \p dst_interface interface on the \p
    dst_node CPU node. Must return 0 if the transfer was actually
    completed completely synchronously, or <c>-EAGAIN</c> if at least
    some transfers are still ongoing and should be awaited for by the
    core.

\var int (*starpu_data_copy_methods::any_to_any)(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void *async_data)
    Define how to copy data from the \p src_interface interface on the
    \p src_node node to the \p dst_interface interface on the \p
    dst_node node. This is meant to be implemented through the
    starpu_interface_copy() helper, to which async_data should be
    passed as such, and will be used to manage asynchronicity. This
    must return <c>-EAGAIN</c> if any of the starpu_interface_copy()
    calls has returned <c>-EAGAIN</c> (i.e. at least some transfer is
    still ongoing), and return 0 otherwise.

\enum starpu_data_interface_id
\ingroup API_Data_Interfaces
Identifier for all predefined StarPU data interfaces
\var starpu_data_interface_id::STARPU_UNKNOWN_INTERFACE_ID
    Unknown interface
\var starpu_data_interface_id::STARPU_MATRIX_INTERFACE_ID
    Identifier for the matrix data interface
\var starpu_data_interface_id::STARPU_BLOCK_INTERFACE_ID
    Identifier for block data interface
\var starpu_data_interface_id::STARPU_VECTOR_INTERFACE_ID
    Identifier for the vector data interface
\var starpu_data_interface_id::STARPU_CSR_INTERFACE_ID
    Identifier for the csr data interface
\var starpu_data_interface_id::STARPU_BCSR_INTERFACE_ID
    Identifier for the bcsr data interface
\var starpu_data_interface_id::STARPU_VARIABLE_INTERFACE_ID
    Identifier for the variable data interface
\var starpu_data_interface_id::STARPU_VOID_INTERFACE_ID
    Identifier for the void data interface
\var starpu_data_interface_id::STARPU_MULTIFORMAT_INTERFACE_ID
    Identifier for the multiformat data interface
\var starpu_data_interface_id::STARPU_COO_INTERFACE_ID
    Identifier for the coo data interface
\var starpu_data_interface_id::STARPU_MAX_INTERFACE_ID
    Maximum number of data interfaces

@name Registering Data
\ingroup API_Data_Interfaces

There are several ways to register a memory region so that it can be
managed by StarPU. The functions below allow the registration of
vectors, 2D matrices, 3D matrices as well as BCSR and CSR sparse
matrices.

\fn void starpu_void_data_register(starpu_data_handle_t *handle)
\ingroup API_Data_Interfaces
Register a void interface. There is no data really associated
to that interface, but it may be used as a synchronization mechanism.
It also permits to express an abstract piece of data that is managed
by the application internally: this makes it possible to forbid the
concurrent execution of different tasks accessing the same <c>void</c>
data in read-write concurrently.

\fn void starpu_variable_data_register(starpu_data_handle_t *handle, int home_node, uintptr_t ptr, size_t size)
\ingroup API_Data_Interfaces
Register the \p size byte element pointed to by \p ptr, which is
typically a scalar, and initialize \p handle to represent this data item.

Here an example of how to use the function.
\code{.c}
float var = 42.0;
starpu_data_handle_t var_handle;
starpu_variable_data_register(&var_handle, STARPU_MAIN_RAM, (uintptr_t)&var, sizeof(var));
\endcode

\fn void starpu_variable_ptr_register(starpu_data_handle_t handle, unsigned node, uintptr_t ptr, uintptr_t dev_handle, size_t offset)
\ingroup API_Data_Interfaces
Register into the \p handle that to store data on node \p node it should use the
buffer located at \p ptr, or device handle \p dev_handle and offset \p offset
(for OpenCL, notably)

\fn void starpu_vector_data_register(starpu_data_handle_t *handle, int home_node, uintptr_t ptr, uint32_t nx, size_t elemsize)
\ingroup API_Data_Interfaces
Register the \p nx \p elemsize-byte elements pointed to by \p ptr and initialize \p handle to represent it.

Here an example of how to use the function.
\code{.c}
float vector[NX];
starpu_data_handle_t vector_handle;
starpu_vector_data_register(&vector_handle, STARPU_MAIN_RAM, (uintptr_t)vector, NX, sizeof(vector[0]));
\endcode

\fn void starpu_vector_ptr_register(starpu_data_handle_t handle, unsigned node, uintptr_t ptr, uintptr_t dev_handle, size_t offset)
\ingroup API_Data_Interfaces
Register into the \p handle that to store data on node \p node it should use the
buffer located at \p ptr, or device handle \p dev_handle and offset \p offset
(for OpenCL, notably)

\fn void starpu_matrix_data_register(starpu_data_handle_t *handle, int home_node, uintptr_t ptr, uint32_t ld, uint32_t nx, uint32_t ny, size_t elemsize)
\ingroup API_Data_Interfaces
Register the \p nx x \p  ny 2D matrix of \p elemsize-byte elements pointed
by \p ptr and initialize \p handle to represent it. \p ld specifies the number
of elements between rows. a value greater than \p nx adds padding, which
can be useful for alignment purposes.

Here an example of how to use the function.
\code{.c}
float *matrix;
starpu_data_handle_t matrix_handle;
matrix = (float*)malloc(width * height * sizeof(float));
starpu_matrix_data_register(&matrix_handle, STARPU_MAIN_RAM, (uintptr_t)matrix, width, width, height, sizeof(float));
\endcode

\fn void starpu_matrix_ptr_register(starpu_data_handle_t handle, unsigned node, uintptr_t ptr, uintptr_t dev_handle, size_t offset, uint32_t ld)
\ingroup API_Data_Interfaces
Register into the \p handle that to store data on node \p node it should use the
buffer located at \p ptr, or device handle \p dev_handle and offset \p offset
(for OpenCL, notably), with \p ld elements between rows.

\fn void starpu_block_data_register(starpu_data_handle_t *handle, int home_node, uintptr_t ptr, uint32_t ldy, uint32_t ldz, uint32_t nx, uint32_t ny, uint32_t nz, size_t elemsize)
\ingroup API_Data_Interfaces
Register the \p nx x \p ny x \p nz 3D matrix of \p elemsize byte elements
pointed by \p ptr and initialize \p handle to represent it. Again, \p ldy and
\p ldz specify the number of elements between rows and between z planes.

Here an example of how to use the function.
\code{.c}
float *block;
starpu_data_handle_t block_handle;
block = (float*)malloc(nx*ny*nz*sizeof(float));
starpu_block_data_register(&block_handle, STARPU_MAIN_RAM, (uintptr_t)block, nx, nx*ny, nx, ny, nz, sizeof(float));
\endcode

\fn void starpu_block_ptr_register(starpu_data_handle_t handle, unsigned node, uintptr_t ptr, uintptr_t dev_handle, size_t offset, uint32_t ldy, uint32_t ldz)
\ingroup API_Data_Interfaces
Register into the \p handle that to store data on node \p node it should use the
buffer located at \p ptr, or device handle \p dev_handle and offset \p offset
(for OpenCL, notably), with \p ldy elements between rows and \p ldz elements between z planes.

\fn void starpu_bcsr_data_register(starpu_data_handle_t *handle, int home_node, uint32_t nnz, uint32_t nrow, uintptr_t nzval, uint32_t *colind, uint32_t *rowptr, uint32_t firstentry, uint32_t r, uint32_t c, size_t elemsize)
\ingroup API_Data_Interfaces
This variant of starpu_data_register() uses the BCSR (Blocked
Compressed Sparse Row Representation) sparse matrix interface.
Register the sparse matrix made of \p nnz non-zero blocks of elements of
size \p elemsize stored in \p nzval and initializes \p handle to represent it.
Blocks have size \p r * \p c. \p nrow is the number of rows (in terms of
blocks), \p colind is an array of nnz elements, colind[i] is the block-column index for block i in \p nzval,
\p rowptr is an array of nrow+1 elements, rowptr[i] is the block-index (in \p nzval) of the first block of row i. By convention, rowptr[nrow] is the number of blocks, this allows an easier access of the matrix's elements for the kernels.
\p firstentry is the index of the first entry of the given arrays
(usually 0 or 1).

Here an example of how to use the function.
\code{.c}
/*
 * We use the following matrix:
 *
 *   +----------------+
 *   |  0   1   0   0 |
 *   |  2   3   0   0 |
 *   |  4   5   8   9 |
 *   |  6   7  10  11 |
 *   +----------------+
 *
 * nzval  = [0, 1, 2, 3] ++ [4, 5, 6, 7] ++ [8, 9, 10, 11]
 * colind = [0, 0, 1]
 * rowptr = [0, 1, 3]
 * r = c = 2
 */

/* Size of the blocks */
int R = 2;
int C = 2;

int NROWS = 2;
int NNZ_BLOCKS = 3;    /* out of 4 */
int NZVAL_SIZE = (R*C*NNZ_BLOCKS);

int nzval[NZVAL_SIZE]  =
{
	0, 1, 2, 3,    /* First block  */
	4, 5, 6, 7,    /* Second block */
	8, 9, 10, 11   /* Third block  */
};
uint32_t colind[NNZ_BLOCKS] =
{
	0, /* block-column index for first block in nzval */
	0, /* block-column index for second block in nzval */
	1  /* block-column index for third block in nzval */
};
uint32_t rowptr[NROWS+1] =
{
	0, / * block-index in nzval of the first block of the first row. */
	1, / * block-index in nzval of the first block of the second row. */
	NNZ_BLOCKS /* number of blocks, to allow an easier element's access for the kernels */
};

starpu_data_handle_t bcsr_handle;
starpu_bcsr_data_register(&bcsr_handle,
			  STARPU_MAIN_RAM,
			  NNZ_BLOCKS,
			  NROWS,
			  (uintptr_t) nzval,
			  colind,
			  rowptr,
			  0, /* firstentry */
			  R,
			  C,
			  sizeof(nzval[0]));
\endcode

\fn void starpu_csr_data_register(starpu_data_handle_t *handle, int home_node, uint32_t nnz, uint32_t nrow, uintptr_t nzval, uint32_t *colind, uint32_t *rowptr, uint32_t firstentry, size_t elemsize)
\ingroup API_Data_Interfaces
This variant of starpu_data_register() uses the CSR (Compressed
Sparse Row Representation) sparse matrix interface. TODO

\fn void starpu_coo_data_register(starpu_data_handle_t *handleptr, int home_node, uint32_t nx, uint32_t ny, uint32_t n_values, uint32_t *columns, uint32_t *rows, uintptr_t values, size_t elemsize);
\ingroup API_Data_Interfaces
Register the \p nx x \p ny 2D matrix given in the COO format, using the
\p columns, \p rows, \p values arrays, which must have \p n_values elements of
size \p elemsize. Initialize \p handleptr.

\fn void *starpu_data_get_interface_on_node(starpu_data_handle_t handle, unsigned memory_node)
\ingroup API_Data_Interfaces
Return the interface associated with \p handle on \p memory_node.

@name Accessing Data Interfaces
\ingroup API_Data_Interfaces

Each data interface is provided with a set of field access functions.
The ones using a <c>void *</c> parameter aimed to be used in codelet
implementations (see for example the code in
\ref VectorScalingUsingStarPUAPI).

\fn void *starpu_data_handle_to_pointer(starpu_data_handle_t handle, unsigned node)
\ingroup API_Data_Interfaces
Return the pointer associated with \p handle on node \p node or <c>NULL</c>
if handle’s interface does not support this operation or data for this
\p handle is not allocated on that \p node.

\fn void *starpu_data_get_local_ptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the local pointer associated with \p handle or <c>NULL</c> if
\p handle’s interface does not have any data allocated locally.

\fn enum starpu_data_interface_id starpu_data_get_interface_id(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the unique identifier of the interface associated with
the given \p handle.

\fn size_t starpu_data_get_size(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the data associated with \p handle.

\fn int starpu_data_pack(starpu_data_handle_t handle, void **ptr, starpu_ssize_t *count)
\ingroup API_Data_Interfaces
Execute the packing operation of the interface of the data
registered at \p handle (see starpu_data_interface_ops). This
packing operation must allocate a buffer large enough at \p ptr and copy
into the newly allocated buffer the data associated to \p handle. \p count
will be set to the size of the allocated buffer. If \p ptr is <c>NULL</c>, the
function should not copy the data in the buffer but just set \p count to
the size of the buffer which would have been allocated. The special
value -1 indicates the size is yet unknown.

\fn int starpu_data_unpack(starpu_data_handle_t handle, void *ptr, size_t count)
\ingroup API_Data_Interfaces
Unpack in handle the data located at \p ptr of size \p count as
described by the interface of the data. The interface registered at
\p handle must define a unpacking operation (see
starpu_data_interface_ops). The memory at the address \p ptr is freed
after calling the data unpacking operation.

@name Accessing Variable Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_variable_interface
\ingroup API_Data_Interfaces
Variable interface for a single data (not a vector, a matrix, a list, ...)
\var enum starpu_data_interface_id starpu_variable_interface::id
    Identifier of the interface
\var uintptr_t starpu_variable_interface::ptr
    local pointer of the variable
\var uintptr_t starpu_variable_interface::dev_handle
    device handle of the variable.
\var size_t starpu_variable_interface::offset
    offset in the variable
\var size_t starpu_variable_interface::elemsize
    size of the variable

\fn size_t starpu_variable_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the variable designated by \p handle.

\fn uintptr_t starpu_variable_get_local_ptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a pointer to the variable designated by \p handle.

\def STARPU_VARIABLE_GET_PTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the variable designated by \p interface.

\def STARPU_VARIABLE_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of the variable designated by \p interface.

\def STARPU_VARIABLE_GET_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the variable designated by
\p interface, to be used with OpenCL. The offset documented below has to be
used in addition to this.

\def STARPU_VARIABLE_GET_OFFSET(interface)
\ingroup API_Data_Interfaces
Return the offset in the variable designated by \p interface, to
be used with the device handle.

@name Accessing Vector Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_vector_interface
Vector interface
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_vector_interface::id
    Identifier of the interface
\var uintptr_t starpu_vector_interface::ptr
    local pointer of the vector
\var uintptr_t starpu_vector_interface::dev_handle
    device handle of the vector.
\var size_t starpu_vector_interface::offset
    offset in the vector
\var uint32_t starpu_vector_interface::nx
    number of elements on the x-axis of the vector
\var size_t starpu_vector_interface::elemsize
    size of the elements of the vector
\var uint32_t starpu_vector_interface::slice_base
    vector slice base, used by the StarPU OpenMP runtime support

\fn uint32_t starpu_vector_get_nx(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements registered into the array designated by \p handle.

\fn size_t starpu_vector_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of each element of the array designated by \p handle.

\fn uintptr_t starpu_vector_get_local_ptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the local pointer associated with \p handle.

\def STARPU_VECTOR_GET_PTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the array designated by \p interface, valid on
CPUs and CUDA only. For OpenCL, the device handle and offset need to
be used instead.

\def STARPU_VECTOR_GET_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the array designated by \p interface,
to be used with OpenCL. the offset documented below has to be used in
addition to this.

\def STARPU_VECTOR_GET_OFFSET(interface)
\ingroup API_Data_Interfaces
Return the offset in the array designated by \p interface, to be
used with the device handle.

\def STARPU_VECTOR_GET_NX(interface)
\ingroup API_Data_Interfaces
Return the number of elements registered into the array
designated by \p interface.

\def STARPU_VECTOR_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of each element of the array designated by
\p interface.

\def STARPU_VECTOR_GET_SLICE_BASE(interface)
\ingroup API_Data_Interfaces
Return the OpenMP slice base annotation of each element of the array designated by
\p interface.

\sa starpu_omp_vector_annotate

@name Accessing Matrix Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_matrix_interface
Matrix interface for dense matrices
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_matrix_interface::id
    Identifier of the interface
\var uintptr_t starpu_matrix_interface::ptr
    local pointer of the matrix
\var uintptr_t starpu_matrix_interface::dev_handle
    device handle of the matrix.
\var size_t starpu_matrix_interface::offset
    offset in the matrix
\var uint32_t starpu_matrix_interface::nx
    number of elements on the x-axis of the matrix
\var uint32_t starpu_matrix_interface::ny
    number of elements on the y-axis of the matrix
\var uint32_t starpu_matrix_interface::ld
    number of elements between each row of the matrix. Maybe be equal
    to starpu_matrix_interface::nx when there is no padding.
\var size_t starpu_matrix_interface::elemsize
    size of the elements of the matrix

\fn uint32_t starpu_matrix_get_nx(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements on the x-axis of the matrix
designated by \p handle.

\fn uint32_t starpu_matrix_get_ny(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements on the y-axis of the matrix
designated by \p handle.

\fn uint32_t starpu_matrix_get_local_ld(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements between each row of the matrix
designated by \p handle. Maybe be equal to nx when there is no padding.

\fn uintptr_t starpu_matrix_get_local_ptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the local pointer associated with \p handle.

\fn size_t starpu_matrix_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the elements registered into the matrix
designated by \p handle.

\def STARPU_MATRIX_GET_PTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the matrix designated by \p interface, valid
on CPUs and CUDA devices only. For OpenCL devices, the device handle
and offset need to be used instead.

\def STARPU_MATRIX_GET_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the matrix designated by \p interface,
to be used with OpenCL. The offset documented below has to be used in
addition to this.

\def STARPU_MATRIX_GET_OFFSET(interface)
\ingroup API_Data_Interfaces
Return the offset in the matrix designated by \p interface, to be
used with the device handle.

\def STARPU_MATRIX_GET_NX(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the x-axis of the matrix
designated by \p interface.

\def STARPU_MATRIX_GET_NY(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the y-axis of the matrix
designated by \p interface.

\def STARPU_MATRIX_GET_LD(interface)
\ingroup API_Data_Interfaces
Return the number of elements between each row of the matrix
designated by \p interface. May be equal to nx when there is no padding.

\def STARPU_MATRIX_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of the elements registered into the matrix
designated by \p interface.

@name Accessing Block Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_block_interface
Block interface for 3D dense blocks
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_block_interface::id
    identifier of the interface
\var uintptr_t starpu_block_interface::ptr
    local pointer of the block
\var uintptr_t starpu_block_interface::dev_handle
    device handle of the block.
\var size_t starpu_block_interface::offset
    offset in the block.
\var uint32_t starpu_block_interface::nx
    number of elements on the x-axis of the block.
\var uint32_t starpu_block_interface::ny
    number of elements on the y-axis of the block.
\var uint32_t starpu_block_interface::nz
    number of elements on the z-axis of the block.
\var uint32_t starpu_block_interface::ldy
    number of elements between two lines
\var uint32_t starpu_block_interface::ldz
    number of elements between two planes
\var size_t starpu_block_interface::elemsize
    size of the elements of the block.

\fn uint32_t starpu_block_get_nx(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements on the x-axis of the block
designated by \p handle.

\fn uint32_t starpu_block_get_ny(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements on the y-axis of the block
designated by \p handle.

\fn uint32_t starpu_block_get_nz(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements on the z-axis of the block
designated by \p handle.

\fn uint32_t starpu_block_get_local_ldy(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements between each row of the block
designated by \p handle, in the format of the current memory node.

\fn uint32_t starpu_block_get_local_ldz(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of elements between each z plane of the block
designated by \p handle, in the format of the current memory node.

\fn uintptr_t starpu_block_get_local_ptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the local pointer associated with \p handle.

\fn size_t starpu_block_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the elements of the block designated by
\p handle.

\def STARPU_BLOCK_GET_PTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the block designated by \p interface.

\def STARPU_BLOCK_GET_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the block designated by \p interface,
to be used on OpenCL. The offset document below has to be used in
addition to this.

\def STARPU_BLOCK_GET_OFFSET(interface)
\ingroup API_Data_Interfaces
Return the offset in the block designated by \p interface, to be
used with the device handle.

\def STARPU_BLOCK_GET_NX(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the x-axis of the block
designated by \p interface.

\def STARPU_BLOCK_GET_NY(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the y-axis of the block
designated by \p interface.

\def STARPU_BLOCK_GET_NZ(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the z-axis of the block
designated by \p interface.

\def STARPU_BLOCK_GET_LDY(interface)
\ingroup API_Data_Interfaces
Return the number of elements between each row of the block
designated by \p interface. May be equal to nx when there is no padding.

\def STARPU_BLOCK_GET_LDZ(interface)
\ingroup API_Data_Interfaces
Return the number of elements between each z plane of the block
designated by \p interface. May be equal to nx*ny when there is no
padding.

\def STARPU_BLOCK_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of the elements of the block designated by
\p interface.

@name Accessing BCSR Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_bcsr_interface
BCSR interface for sparse matrices (blocked compressed sparse
row representation)
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_bcsr_interface::id
    Identifier of the interface
\var uint32_t starpu_bcsr_interface::nnz
    number of non-zero BLOCKS
\var uint32_t starpu_bcsr_interface::nrow
    number of rows (in terms of BLOCKS)
\var uintptr_t starpu_bcsr_interface::nzval
    non-zero values
\var uint32_t *starpu_bcsr_interface::colind
    array of nnz elements, colind[i] is the block-column index for block i in nzval
\var uint32_t *starpu_bcsr_interface::rowptr
    array of nrow+1 elements, rowptr[i] is the block-index (in nzval) of the first block of row i. By convention, rowptr[nrow] is the number of blocks, this allows an easier access of the matrix's elements for the kernels.
\var starpu_bcsr_interface::firstentry
    k for k-based indexing (0 or 1 usually). Also useful when partitionning the matrix.
\var uint32_t starpu_bcsr_interface::r
    height of the blocks
\var uint32_t starpu_bcsr_interface::c
    width of the blocks
\var size_t starpu_bcsr_interface::elemsize
    size of the elements of the matrix

\fn uint32_t starpu_bcsr_get_nnz(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of non-zero elements in the matrix designated
by \p handle.

\fn uint32_t starpu_bcsr_get_nrow(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of rows (in terms of blocks of size r*c) in
the matrix designated by \p handle.

\fn uint32_t starpu_bcsr_get_firstentry(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the index at which all arrays (the column indexes, the
row pointers...) of the matrix desginated by \p handle.

\fn uintptr_t starpu_bcsr_get_local_nzval(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a pointer to the non-zero values of the matrix
designated by \p handle.

\fn uint32_t *starpu_bcsr_get_local_colind(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a pointer to the column index, which holds the positions
of the non-zero entries in the matrix designated by \p handle.

\fn uint32_t *starpu_bcsr_get_local_rowptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the row pointer array of the matrix designated by
\p handle.

\fn uint32_t starpu_bcsr_get_r(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of rows in a block.

\fn uint32_t starpu_bcsr_get_c(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of columns in a block.

\fn size_t starpu_bcsr_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the elements in the matrix designated by
\p handle.

\def STARPU_BCSR_GET_NNZ(interface)
\ingroup API_Data_Interfaces
Return the number of non-zero values in the matrix designated
by \p interface.

\def STARPU_BCSR_GET_NZVAL(interface)
\ingroup API_Data_Interfaces
Return a pointer to the non-zero values of the matrix
designated by \p interface.

\def STARPU_BCSR_GET_NZVAL_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the array of non-zero values in the
matrix designated by \p interface. The offset documented below has to be
used in addition to this.

\def STARPU_BCSR_GET_COLIND(interface)
\ingroup API_Data_Interfaces
Return a pointer to the column index of the matrix designated
by \p interface.

\def STARPU_BCSR_GET_COLIND_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the column index of the matrix
designated by \p interface. The offset documented below has to be used in
addition to this.

\def STARPU_BCSR_GET_ROWPTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the row pointer array of the matrix
designated by \p interface.

\def STARPU_BCSR_GET_ROWPTR_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the row pointer array of the matrix
designated by \p interface. The offset documented below has to be used in
addition to this.

\def STARPU_BCSR_GET_OFFSET
\ingroup API_Data_Interfaces
Return the offset in the arrays (coling, rowptr, nzval) of the
matrix designated by \p interface, to be used with the device handles.

@name Accessing CSR Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_csr_interface
CSR interface for sparse matrices (compressed sparse row representation)
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_csr_interface::id
    Identifier of the interface
\var uint32_t starpu_csr_interface::nnz
    number of non-zero entries
\var uint32_t starpu_csr_interface::nrow
    number of rows
\var uintptr_t starpu_csr_interface::nzval
    non-zero values
\var uint32_t *starpu_csr_interface::colind
    position of non-zero entries on the row
\var uint32_t *starpu_csr_interface::rowptr
    index (in nzval) of the first entry of the row
\var uint32_t starpu_csr_interface::firstentry
    k for k-based indexing (0 or 1 usually). also useful when partitionning the matrix.
\var size_t starpu_csr_interface::elemsize
    size of the elements of the matrix

\fn uint32_t starpu_csr_get_nnz(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the number of non-zero values in the matrix designated
by \p handle.

\fn uint32_t starpu_csr_get_nrow(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the row pointer array of the matrix
designated by \p handle.

\fn uint32_t starpu_csr_get_firstentry(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the index at which all arrays (the column indexes, the
row pointers...) of the matrix designated by \p handle.

\fn uintptr_t starpu_csr_get_local_nzval(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a local pointer to the non-zero values of the matrix
designated by \p handle.

\fn uint32_t *starpu_csr_get_local_colind(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a local pointer to the column index of the matrix
designated by \p handle.

\fn uint32_t *starpu_csr_get_local_rowptr(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return a local pointer to the row pointer array of the matrix
designated by \p handle.

\fn size_t starpu_csr_get_elemsize(starpu_data_handle_t handle)
\ingroup API_Data_Interfaces
Return the size of the elements registered into the matrix
designated by \p handle.

\def STARPU_CSR_GET_NNZ(interface)
\ingroup API_Data_Interfaces
Return the number of non-zero values in the matrix designated
by \p interface.

\def STARPU_CSR_GET_NROW(interface)
\ingroup API_Data_Interfaces
Return the size of the row pointer array of the matrix
designated by \p interface.

\def STARPU_CSR_GET_NZVAL(interface)
\ingroup API_Data_Interfaces
Return a pointer to the non-zero values of the matrix
designated by \p interface.

\def STARPU_CSR_GET_NZVAL_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the array of non-zero values in the
matrix designated by \p interface. The offset documented below has to be
used in addition to this.

\def STARPU_CSR_GET_COLIND(interface)
\ingroup API_Data_Interfaces
Return a pointer to the column index of the matrix designated
by \p interface.

\def STARPU_CSR_GET_COLIND_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the column index of the matrix
designated by \p interface. The offset documented below has to be used in
addition to this.

\def STARPU_CSR_GET_ROWPTR(interface)
\ingroup API_Data_Interfaces
Return a pointer to the row pointer array of the matrix
designated by \p interface.

\def STARPU_CSR_GET_ROWPTR_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the row pointer array of the matrix
designated by \p interface. The offset documented below has to be used in
addition to this.

\def STARPU_CSR_GET_OFFSET
\ingroup API_Data_Interfaces
Return the offset in the arrays (colind, rowptr, nzval) of the
matrix designated by \p interface, to be used with the device handles.

\def STARPU_CSR_GET_FIRSTENTRY(interface)
\ingroup API_Data_Interfaces
Return the index at which all arrays (the column indexes, the
row pointers...) of the \p interface start.

\def STARPU_CSR_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of the elements registered into the matrix
designated by \p interface.

@name Accessing COO Data Interfaces
\ingroup API_Data_Interfaces

\struct starpu_coo_interface
COO Matrices
\ingroup API_Data_Interfaces
\var enum starpu_data_interface_id starpu_coo_interface::id
    identifier of the interface
\var uint32_t  *starpu_coo_interface::columns
    column array of the matrix
\var uint32_t  *starpu_coo_interface::rows
    row array of the matrix
\var uintptr_t starpu_coo_interface::values
    values of the matrix
\var uint32_t  starpu_coo_interface::nx
    number of elements on the x-axis of the matrix
\var uint32_t  starpu_coo_interface::ny
    number of elements on the y-axis of the matrix
\var uint32_t  starpu_coo_interface::n_values
    number of values registered in the matrix
\var size_t starpu_coo_interface::elemsize
    size of the elements of the matrix

\def STARPU_COO_GET_COLUMNS(interface)
\ingroup API_Data_Interfaces
Return a pointer to the column array of the matrix designated
by \p interface.

\def STARPU_COO_GET_COLUMNS_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the column array of the matrix
designated by \p interface, to be used with OpenCL. The offset documented
below has to be used in addition to this.

\def STARPU_COO_GET_ROWS(interface)
\ingroup API_Data_Interfaces
Return a pointer to the rows array of the matrix designated by
\p interface.

\def STARPU_COO_GET_ROWS_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the row array of the matrix
designated by \p interface, to be used on OpenCL. The offset documented
below has to be used in addition to this.

\def STARPU_COO_GET_VALUES(interface)
\ingroup API_Data_Interfaces
Return a pointer to the values array of the matrix designated
by \p interface.

\def STARPU_COO_GET_VALUES_DEV_HANDLE(interface)
\ingroup API_Data_Interfaces
Return a device handle for the value array of the matrix
designated by \p interface, to be used on OpenCL. The offset documented
below has to be used in addition to this.

\def STARPU_COO_GET_OFFSET
\ingroup API_Data_Interfaces
Return the offset in the arrays of the COO matrix designated by
\p interface.

\def STARPU_COO_GET_NX(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the x-axis of the matrix
designated by \p interface.

\def STARPU_COO_GET_NY(interface)
\ingroup API_Data_Interfaces
Return the number of elements on the y-axis of the matrix
designated by \p interface.

\def STARPU_COO_GET_NVALUES(interface)
\ingroup API_Data_Interfaces
Return the number of values registered in the matrix designated
by \p interface.

\def STARPU_COO_GET_ELEMSIZE(interface)
\ingroup API_Data_Interfaces
Return the size of the elements registered into the matrix
designated by \p interface.

@name Defining Interface
\ingroup API_Data_Interfaces

Applications can provide their own interface as shown in
\ref DefiningANewDataInterface.

\fn uintptr_t starpu_malloc_on_node_flags(unsigned dst_node, size_t size, int flags)
\ingroup API_Data_Interfaces
Allocate \p size bytes on node \p dst_node with the given allocation \p flags. This returns 0 if
allocation failed, the allocation method should then return <c>-ENOMEM</c> as
allocated size. Deallocation must be done with starpu_free_on_node().

\fn void starpu_free_on_node_flags(unsigned dst_node, uintptr_t addr, size_t size, int flags)
\ingroup API_Data_Interfaces
Free \p addr of \p size bytes on node \p dst_node which was previously allocated
with starpu_malloc_on_node() with the given allocation \p flags.

\fn uintptr_t starpu_malloc_on_node(unsigned dst_node, size_t size)
\ingroup API_Data_Interfaces
Allocate \p size bytes on node \p dst_node with the default allocation flags. This returns 0 if
allocation failed, the allocation method should then return <c>-ENOMEM</c> as
allocated size. Deallocation must be done with starpu_free_on_node().

\fn void starpu_free_on_node(unsigned dst_node, uintptr_t addr, size_t size)
\ingroup API_Data_Interfaces
Free \p addr of \p size bytes on node \p dst_node which was previously allocated
with starpu_malloc_on_node().

\fn void starpu_malloc_on_node_set_default_flags(unsigned node, int flags)
\ingroup API_Data_Interfaces
Define the default flags for allocations performed by starpu_malloc_on_node() and
starpu_free_on_node(). The default is \ref STARPU_MALLOC_PINNED | \ref STARPU_MALLOC_COUNT.

\fn int starpu_interface_copy(uintptr_t src, size_t src_offset, unsigned src_node, uintptr_t dst, size_t dst_offset, unsigned dst_node, size_t size, void *async_data)
\ingroup API_Data_Interfaces
Copy \p size bytes from byte offset \p src_offset of \p src on \p src_node
to byte offset \p dst_offset of \p dst on \p dst_node. This is to be used in
the starpu_data_copy_methods::any_to_any copy method, which is provided with \p async_data to
be passed to starpu_interface_copy(). this returns <c>-EAGAIN</c> if the
transfer is still ongoing, or 0 if the transfer is already completed.

\fn uint32_t starpu_hash_crc32c_be_n(const void *input, size_t n, uint32_t inputcrc)
\ingroup API_Data_Interfaces
Compute the CRC of a byte buffer seeded by the \p inputcrc
<em>current state</em>. The return value should be considered as the new
<em>current state</em> for future CRC computation. This is used for computing
data size footprint.

\fn uint32_t starpu_hash_crc32c_be(uint32_t input, uint32_t inputcrc)
\ingroup API_Data_Interfaces
Compute the CRC of a 32bit number seeded by the \p inputcrc
<em>current state</em>. The return value should be considered as the new
<em>current state</em> for future CRC computation. This is used for computing
data size footprint.

\fn uint32_t starpu_hash_crc32c_string(const char *str, uint32_t inputcrc)
\ingroup API_Data_Interfaces
Compute the CRC of a string seeded by the \p inputcrc <em>current
state</em>. The return value should be considered as the new <em>current
state</em> for future CRC computation. This is used for computing data
size footprint.

\fn int starpu_data_interface_get_next_id(void)
\ingroup API_Data_Interfaces
Return the next available id for a newly created data interface
(\ref DefiningANewDataInterface).

*/