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Parallelize

Parallelize[expr]
evaluates expr using automatic parallelization.
  • Parallelize[expr] automatically distributes different parts of the evaluation of expr among different available kernels and processors.
  • Parallelize[expr] normally gives the same result as evaluating expr, except for side effects during the computation.
  • The Method option for Parallelize specifies the parallelization method to use. Possible settings include:
"CoarsestGrained"break the computation into as many pieces as there are available kernels
"FinestGrained"break the computation into the smallest possible subunits
"EvaluationsPerKernel"→ebreak the computation into at most e pieces per kernel
"ItemsPerEvaluation"→mbreak the computation into evaluations of at most m subunits each
Automaticcompromise between overhead and load-balancing
  • Method->"CoarsestGrained" is suitable for computations involving many subunits, all of which take the same amount of time. It minimizes overhead, but does not provide any load balancing.
  • Method->"FinestGrained" is suitable for computations involving few subunits whose evaluations take different amounts of time. It leads to higher overhead, but maximizes load balancing.
EXAMPLESCLOSE ALL
Basic Examples   (3)
Functions used need to be distributed first:
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Functions used need to be distributed first:
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Scope   (11)
The result need not have the same length as the input:
Without a function, Parallelize simply evaluates the elements in parallel:
Count the number of primes up to one million:
Check whether 93 occurs in a list of the first 100 primes:
Evaluate a table in parallel, with or without an iterator variable:
Evaluate a product in parallel:
Possible Issues   (1)
Expressions that cannot be parallelized are evaluated normally:
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