50 lines
1.5 KiB
Scheme
50 lines
1.5 KiB
Scheme
;;; DERIV -- Symbolic derivation.
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(library (rnrs-benchmarks deriv)
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(export main)
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(import (rnrs) (rnrs-benchmarks))
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;;; Returns the wrong answer for quotients.
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;;; Fortunately these aren't used in the benchmark.
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(define (deriv a)
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(cond ((not (pair? a))
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(if (eq? a 'x) 1 0))
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((eq? (car a) '+)
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(cons '+
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(map deriv (cdr a))))
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((eq? (car a) '-)
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(cons '-
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(map deriv (cdr a))))
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((eq? (car a) '*)
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(list '*
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a
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(cons '+
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(map (lambda (a) (list '/ (deriv a) a)) (cdr a)))))
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((eq? (car a) '/)
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(list '-
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(list '/
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(deriv (cadr a))
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(caddr a))
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(list '/
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(cadr a)
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(list '*
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(caddr a)
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(caddr a)
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(deriv (caddr a))))))
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(else
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(fatal-error "No derivation method available"))))
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(define (main . args)
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(run-benchmark
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"deriv"
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deriv-iters
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(lambda (result)
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(equal? result
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'(+ (* (* 3 x x) (+ (/ 0 3) (/ 1 x) (/ 1 x)))
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(* (* a x x) (+ (/ 0 a) (/ 1 x) (/ 1 x)))
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(* (* b x) (+ (/ 0 b) (/ 1 x)))
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0)))
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(lambda (a) (lambda () (deriv a)))
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'(+ (* 3 x x) (* a x x) (* b x) 5))))
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