Make sure parallel subkernels are launched:

Values used in subkernels need to be distributed first:

Symbols in the default context are distributed automatically:

Values of variables:

Functions:

Upvalues:

Attributes:

Distribute definitions for all symbols in the current context:

Auxiliary definitions on which a distributed definition depends are also automatically distributed:

DistributeDefinitions overwrites any previous values and attributes present:

Remove a distributed definition by clearing the function and distributing it again:

DistributeDefinitions uses ParallelEvaluate to transport definitions to all kernels:

An explicit ParallelEvaluate does the same:

Distributed definitions are remembered for new kernels; the effect of ParallelEvaluate is not:

For higher-level parallel commands, functions defined interactively are automatically distributed:

Distribute definitions manually and disable automatic distribution:

Symbols that have values only on the subkernels are not distributed:

The values on the subkernels remain intact:

As soon as a symbol gets a local value, it will be distributed with the next parallel computation:

Use ParallelNeeds to set up a package on all parallel kernels:

Use DistributeDefinitions to set up your own definitions:

$DistributedDefinitions gives the list of all symbols whose definitions have been distributed:

The list also includes symbols that were distributed automatically:

A function used that is not known on the parallel kernels may lead to sequential evaluation:

Define the function on all parallel kernels:

The function is now evaluated on the parallel kernels:

The use of DistributeDefinitions does not suppress automatic distribution of definitions:

Modify the definition:

The modified definition is automatically distributed:

Suppress the automatic distribution of definitions:

Symbols defined only on the subkernels are not distributed automatically:

Certain objects with an internal state may not work efficiently when distributed:

Recompute such objects on all subkernels for better performance:

Alternatively, reevaluate the data on all subkernels:

Definitions of symbols with the ReadProtected attribute cannot be distributed:

Definitions are only distributed as needed; if a definition has not changed, it is not distributed again:

Both symbols are still distributed: