NB. par.ijs - Parallel execution utilities for J
NB. Provides 'par' and 'parr' for easy parallel map operations
NB.
NB. Uses threadpool 1 (separate from pool 0 used by J primitives)
NB. to avoid interference with other threaded operations.

NB. =========================================================
NB. Configuration (in z locale for global access)
NB. =========================================================

NB. Threadpool number for par operations (1 = separate from primitives)
par_POOL_z_ =: 1

NB. Get number of CPU cores (8 T. '' returns corecount,maxthreads)
par_cores_z_ =: {. 8 T. ''

NB. =========================================================
NB. Thread pool management
NB. =========================================================

NB. Initialize threadpool with n workers
par_init_z_ =: 3 : 0
  for_i. i. y do.
    0 T. < par_POOL
  end.
  par_workers''
)

NB. Get worker count in our pool
par_workers_z_ =: 3 : '{: 2 T. par_POOL'

NB. Get pool statistics (idle, pending, total)
par_status_z_ =: 3 : '2 T. par_POOL'

NB. =========================================================
NB. Parallel execution adverbs/conjunctions
NB. =========================================================

NB. par - Parallel map at rank _1 (items)
NB. Usage: verb par array
NB. Example: *: par i.100
NB.          +/ par matrix   NB. sum each row
par_z_ =: 1 : '>@(u t. par_POOL "_1)'

NB. parr - Parallel map conjunction with configurable rank
NB. Usage: verb parr rank array
NB. Example: *: parr 0 i.100   NB. each atom
NB.          +/ parr 1 matrix  NB. each row
parr_z_ =: 2 : '>@(u t. par_POOL " n)'

NB. =========================================================
NB. Auto-initialize on load
NB. =========================================================

NB. Initialize with cores-1 workers in pool 1
par_init par_cores - 1

smoutput 'par.ijs loaded: ', (": par_workers''), ' workers in pool ', (": par_POOL), ' (', (": par_cores), ' cores)'