CRAC

This method returns the current task identifier. This number ranges from 0 to nbTask-1.

N.B.: the task identifier is determined automatically by CRAC, using the XML file that describes the execution context.

This method returns the number of tasks involved in the current execution.

This method returns the argument array for the task taskId

N.B.: the array is given by the user in the XML file that describes the execution context.

This method returns the number of argument passed to the task taskId

CAUTION: this method should never be used in "normal" code. It is only provided for debugging purposes

This method returns the daemon identifier that hosts the current task. This number ranges from 0 to nbDaemon-1.

N.B.: the daemon identifier is determined automatically by CRAC, using the XML file that describes the VDM.

CAUTION: this method should never be used in "normal" code. It is only provided for debugging purposes

A node represents the computing entity hosted by the daemon for an execution. It may contains several tasks. This method returns the rank of the current task in the node.

N.B.: the rank is determined automatically by CRAC, using the XML file that describes the execution context.

This method returns an absolute time as a double. In order to measure a time gap, two calls must be done, as shown below.

double gap = CRACGetLocalTime();
...
...
gap = CRACGetLocalTime() - gap;
cout << "elapsed time : " << gap << "s" << endl;
  

This method sends a message of size size to task dest, containing bytes given in data and marked with the tag tag. The first byte sent is byte 0 of data.

N.B.: this method never blocks and returns nearly immediately. It simply copies the data in the sending queues used by the Sender thread.

This method tries to receive a message of size size from task src, marked with the tag tag, storing bytes in data. The first byte received is stored at index 0 of data.

mode indicates if the call is blocking or not. Two values are possible :

• CRAC_NOBLOCK: if no message with the given source and tag exists in the reception queues, the method return -1. Else, it fills data and returns the real size of the message (may be < size)
• CRAC_BLOCK: the method blocks until a message with the given source and tag exists in the reception queues. Then, it fills data and returns the real size of the message (may be < size)

N.B.: obviously, this call must be chosen blocking for SIAC executions and not blocking for AIAC.

This method manages all operations bounded to local/global convergence. There are two types of operation, depending on the value of op:

• CRAC_GET_CONV: the method sends the local convergence state set and returns the global convergence state. It may return immediately or not (see below).
• CRAC_RESET_CONV: the method resets the local/global convergence state to false and returns true. This operation is used when an application does several series of iterations and must detect the global convergence for each.

In case of op = CRAC_RESET_CONV, mode indicates if the call is blocking or not. Two values are possible :

• CRAC_NOBLOCK: if no message saying the global convergence has been reached exists in the reception queues, the method return false. Else, it returns true.
• CRAC_BLOCK: the method blocks until a message with the global convergence state exists in the reception queues. Then, it returns this state which may be true or false, depending on if the global convergence has been reached.

N.B.: obviously, this call must be chosen blocking for SIAC executions and not blocking for AIAC.

The task src broadcasts to all other tasks a message of size size, containing bytes given in data. The first byte sent is byte 0 of data. All other tasks store the message in data.

N.B. 1: this method use a binary tree over all tasks to achieve the broadcast in a minimal communication steps. Thus, a task may receive the message from a task != src.

N.B. 2: this method is blocking until the broadcasted message is received. Internally, an acknowledgment is sent to the sender immediately after the reception.

N.B. 3: This method (like CRACBarrier()) must be called by all tasks. If it is not the case, some tasks may be blocked because an acknowledgment is missing.

This method allows to insert a synchronization point of all tasks during the execution.

N.B. 1: this method uses a decentralized algorithm that implies only one communication with each neighbors. Thus, it is minimal in communication steps and bandwidth use.

N.B. 2: This method (like CRACBroadcast()) must be called by all tasks. If it is not the case, some tasks may be blocked because an internal acknowledgment is missing.

This method allows to end correctly an execution. In fact, it is a special barrier.

This method allows to set some internals parameters of CRAC. It should never be used, except with what = CRAC_ITER_CONV. The second parameter is an integer value. It is only used for AIAC executions. It fixes the number of iterations the supermaster waits for when the global convergence has been reached. Passed this number, it warns all tasks. Waiting for few iterations allows to possibly receive a message saying a task has no more a convergence state set to true.