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exist

Check whether Composite is defined on workers

Syntax

h = exist(C,labidx)
h = exist(C)

Description

h = exist(C,labidx) returns true if the entry in Composite C has a defined value on the worker with spmdIndex labidx, false otherwise. In the general case where labidx is an array, the output h is an array of the same size as labidx, and h(i) indicates whether the Composite entry labidx(i) has a defined value.

h = exist(C) is equivalent to h = exist(C, 1:length(C)).

If exist(C,labidx) returns true, C(labidx) does not throw an error, provided that the values of C on those workers are serializable. The function throws an error if any labidx is invalid.

Examples

Define a variable on a random number of workers. Check on which workers the Composite entries are defined, and get all those values: 

 spmd
   if rand() > 0.5
       c = spmdIndex;
   end
 end
 ind = exist(c);
 cvals = c(ind);

Version History

Introduced in R2008b

See Also