52 lines
1.3 KiB
Scheme
52 lines
1.3 KiB
Scheme
;;; DERIV -- Symbolic derivation.
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(import (scheme base)
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(scheme read)
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(scheme write)
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(scheme cxr))
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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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(error #f "No derivation method available"))))
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(define (main)
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(let* ((count (read))
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(input1 (read))
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(output (read))
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(s (number->string count))
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(name "deriv"))
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(run-r7rs-benchmark
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(string-append name ":" s)
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count
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(lambda () (deriv (hide count input1)))
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(lambda (result) (equal? result output)))))
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(include "src/common.sch")
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