22 lines
490 B
Racket
22 lines
490 B
Racket
#lang racket
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(require data/queue)
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(define (simple-moving-average period)
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(define queue (make-queue))
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(define sum 0.0)
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(lambda (x)
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(enqueue! queue x)
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(set! sum (+ sum x))
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(when (> (queue-length queue) period)
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(set! sum (- sum (dequeue! queue))))
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(/ sum (queue-length queue))))
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;; Tests
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(define sma3 (simple-moving-average 3))
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(define sma5 (simple-moving-average 5))
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(for/lists (lst1 lst2)
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([i '(1 2 3 4 5 5 4 3 2 1)])
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(values (sma3 i) (sma5 i)))
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