Hardware Locality (hwloc): Add distances between objects

Hardware Locality (hwloc) 2.14.0rc1

Typedefs | Enumerations | Functions
Add distances between objects

## Typedefs
typedef void * | hwloc_distances_add_handle_t

## Enumerations
enum | hwloc_distances_add_flag_e { HWLOC_DISTANCES_ADD_FLAG_GROUP , HWLOC_DISTANCES_ADD_FLAG_GROUP_INACCURATE }

## Functions
hwloc_distances_add_handle_t | hwloc_distances_add_create (hwloc_topology_t topology, const char *name, unsigned long kind, unsigned long flags)
int | hwloc_distances_add_values (hwloc_topology_t topology, hwloc_distances_add_handle_t handle, unsigned nbobjs, hwloc_obj_t *objs, hwloc_uint64_t *values, unsigned long flags)
int | hwloc_distances_add_commit (hwloc_topology_t topology, hwloc_distances_add_handle_t handle, unsigned long flags)

## Detailed Description

The usual way to add distances is:

hwloc_distances_add_handle_t handle;
int err = -1;
handle = hwloc_distances_add_create(topology, "name", kind, 0);
if (handle) {
err = hwloc_distances_add_values(topology, handle, nbobjs, objs, values, 0);
if (!err)
err = hwloc_distances_add_commit(topology, handle, flags);
}
hwloc_distances_add_commit
int hwloc_distances_add_commit(hwloc_topology_t topology, hwloc_distances_add_handle_t handle, unsigned long flags)
Commit a new distances structure.
hwloc_distances_add_handle_t
void * hwloc_distances_add_handle_t
Handle to a new distances structure during its addition to the topology.
Definition distances.h:355
hwloc_distances_add_create
hwloc_distances_add_handle_t hwloc_distances_add_create(hwloc_topology_t topology, const char *name, unsigned long kind, unsigned long flags)
Create a new empty distances structure.
hwloc_distances_add_values
int hwloc_distances_add_values(hwloc_topology_t topology, hwloc_distances_add_handle_t handle, unsigned nbobjs, hwloc_obj_t *objs, hwloc_uint64_t *values, unsigned long flags)
Specify the objects and values in a new empty distances structure.

If `err` is `0` at the end, then addition was successful.

## Typedef Documentation

## ◆ hwloc_distances_add_handle_t

typedef void* hwloc_distances_add_handle_t

Handle to a new distances structure during its addition to the topology.

## Enumeration Type Documentation

## ◆ hwloc_distances_add_flag_e

enum hwloc_distances_add_flag_e

Flags for adding a new distances to a topology.

Enumerator
HWLOC_DISTANCES_ADD_FLAG_GROUP | Try to group objects based on the newly provided distance information. Grouping is only performed when the distances structure contains latencies, and when all objects are of the same type.
HWLOC_DISTANCES_ADD_FLAG_GROUP_INACCURATE | If grouping, consider the distance values as inaccurate and relax the comparisons during the grouping algorithms. The actual accuracy may be modified through the HWLOC_GROUPING_ACCURACY environment variable (see Environment variables for tweaking hwloc heuristics).

## Function Documentation

## ◆ hwloc_distances_add_commit()

int hwloc_distances_add_commit | ( | hwloc_topology_t | topology,
|  | hwloc_distances_add_handle_t | handle,
|  | unsigned long | flags )

Commit a new distances structure.

This function finalizes the distances structure and inserts in it the topology.

Parameter `handle` was previously returned by hwloc_distances_add_create(). Then objects and values were specified with hwloc_distances_add_values().

`flags` configures the behavior of the function using an optional OR'ed set of hwloc_distances_add_flag_e. It may be used to request the grouping of existing objects based on distances.

On error, the temporary distances structure and its content are destroyed.

Returns
  0 on success.
  -1 on error.

## ◆ hwloc_distances_add_create()

hwloc_distances_add_handle_t hwloc_distances_add_create | ( | hwloc_topology_t | topology,
|  | const char * | name,
|  | unsigned long | kind,
|  | unsigned long | flags )

Create a new empty distances structure.

Create an empty distances structure to be filled with hwloc_distances_add_values() and then committed with hwloc_distances_add_commit().

Parameter `name` is optional, it may be `NULL`. Otherwise, it will be copied internally and may later be freed by the caller.

`kind` specifies the kind of distance as a OR'ed set of hwloc_distances_kind_e. Only one kind of meaning and one kind of provenance may be given if appropriate (e.g. HWLOC_DISTANCES_KIND_MEANS_BANDWIDTH and HWLOC_DISTANCES_KIND_FROM_USER). Kind HWLOC_DISTANCES_KIND_HETEROGENEOUS_TYPES will be automatically set according to objects having different types in hwloc_distances_add_values().

`flags` must be `0` for now.

Returns
  A hwloc_distances_add_handle_t that should then be passed to hwloc_distances_add_values() and hwloc_distances_add_commit().
  `NULL` on error.

## ◆ hwloc_distances_add_values()

int hwloc_distances_add_values | ( | hwloc_topology_t | topology,
|  | hwloc_distances_add_handle_t | handle,
|  | unsigned | nbobjs,
|  | hwloc_obj_t * | objs,
|  | hwloc_uint64_t * | values,
|  | unsigned long | flags )

Specify the objects and values in a new empty distances structure.

Specify the objects and values for a new distances structure that was returned as a handle by hwloc_distances_add_create(). The structure must then be committed with hwloc_distances_add_commit().

The number of objects is `nbobjs` and the array of objects is `objs`. Distance values are stored as a one-dimension array in `values`. The distance from object i to object j is in slot i*nbobjs+j.

`nbobjs` must be at least 2.

Arrays `objs` and `values` will be copied internally, they may later be freed by the caller.

On error, the temporary distances structure and its content are destroyed.

`flags` must be `0` for now.

Returns
  0 on success.
  -1 on error.