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Shared::SharedArray

SharedArray constructs an array of shared elements. The array is replicated globally across SST's ranks and threads. The array can be written during SST's construction and/or init stages and becomes read-only either when all the components that have initialized the array also publish it or when the setup stage begins, whichever is first.

Before the array becomes read-only, components should use caution with functions that are not thread-safe as the array may be modified by other threads concurrently.

Constructor​

Shared::SharedArray<T>();
Shared::SharedArray<bool>(); // Special case that uses std::vector<bool> for storage

The template type T must be a non-pointer type and must be serializable.

initialize​

int initialize(const std::string& obj_name, size_t length = 0, T init_value = T(), verify_type v_type = INIT_VERIFY);

Initializes the SharedArray and returns the number of components (on the current rank) that have already initialized the array.

Parameters​

  • obj_name (std::string) The name of the object to initialize.
  • length (size_t) The size of the array. The array will be the maximum size initialized by any component.
  • init_value (T) A default value to give array elements. If not provided, the default constructor for type T is used.
  • v_type (verify_type) A conflict resolution policy: INIT_VERIFY (default), FE_VERIFY, or NO_VERIFY.
  • returns (int) The number of components on the current rank that have already initialized the array.

Error conditions​

  • Components may only call initialize once on each object.
  • Components may not initialize the same object with different verify_type arguments.
  • Initialize must be called prior to SST's setup stage.
  • The size of the array will be the maximum of the 'length' parameters provided in the initialize calls. Writing/reading beyond this length is not allowed.

begin​

const_iterator begin();

Returns a const iterator to the beginning of the array. If called prior to the SharedArray becoming read-only, the returned iterator could become invalid if the array is resized.

Parameters​

  • returns (const_iterator) A const iterator to the beginning of the array.

empty​

bool empty();

Returns whether array is empty. Thread-safe.

Parameters​

  • returns (bool) True if array is empty (size == 0), false otherwise.

end​

const_iterator end();

Returns a const iterator to the end of the array. If called prior to the SharedArray becoming read-only, the returned iterator could become invalid if the array is resized.

Parameters​

  • returns (const_iterator) A const iterator to the end of the array.

isFullyPublished​

bool isFullyPublished();

Returns whether every component that has initialized the array has also published it. Note that it is possible for isFullyPublished() to return true in one phase of init and return false in a subsequent phase if a component initializes the array between the calls to isFullyPublished() (e.g., during the init stage).

Parameters​

  • returns (bool) True if every component that has initialized the SharedArray has also published it, false otherwise.

mutex_read​

const T& mutex_read(int index);

Returns the value at the specified index. This is thread-safe and can be used prior to the array becoming read-only.

Parameters​

  • index (int) Index to read from.
  • returns (const T) A const reference to the value at the specified index.

operator[]​

const T& operator[](int index);

Returns the value at the specified index. This is not thread-safe. Prior to the array becoming read-only, use mutex_read() instead.

Parameters​

  • index (int) Index to read from.
  • returns (const T) A const reference to the value at the specified index.

publish​

void publish();

Changes the state of the SharedArray to read-only for the calling component. A component may not write the array after publishing it.

Parameters​

  • returns None.

rbegin​

const_reverse_iterator rbegin();

Returns a const reverse_iterator to the beginning of the array. If called prior to the SharedArray becoming read-only, the returned iterator could become invalid if the array is resized.

Parameters​

  • returns (const_reverse_iterator) A const reverse_iterator to the beginning of the array.

rend​

const_reverse_iterator rend();

Returns a const reverse_iterator to the end of the array. If called prior to the SharedArray becoming read-only, the returned iterator could become invalid if the array is resized.

Parameters​

  • returns (const_reverse_iterator) A const reverse_iterator to the end of array.

size​

size_t size();

Returns the size of the array. Thread safe.

Parameters​

  • returns (size_t) Size of the array.

write​

void write(int index, const T& value);

Write value to the specified index. This function can be used after calling initialize and prior to calling publish. It is thread-safe.

Parameters​

  • index (int) Index to write to.
  • value (const T) Value to write.
  • returns None
#include <sst/core/shared/sharedArray.h