[plt-scheme] Undefined Identifier?

From: Adamson, Joel J. (JADAMSON at PARTNERS.ORG)
Date: Mon Oct 22 15:21:58 EDT 2007

Dear List,

I have a module that works just fine, and then I added a (provide/contract ) and
now I get these run-time errors.  The other change I made was to import some new
modules to cover the provide/contract.

> (require "leslie.ss")
> (define queen   (build-L-hash     delta
reference to an identifier before its definition: build-L-hash in module:
> (neXt-gen monkey (make-f64vector 5 100) 10)
reference to undefined identifier: lifted.3

The module is below.  As far as I can tell, I'm not referencing build-L-hash
before I define it, except in the provide, which never mattered before.  And
what does "lifted.3" mean?  

Where do I go to find these errors?  The deepest debugging I do is using trace.
What else should I use?  I'm using MzScheme 371 from SVN (fairly recent).  No
DrScheme or MrED. 


(module leslie mzscheme
   (lib "compat.ss")
   (lib "foreign.ss")
   (all-except (lib "list.ss" "srfi" "1") any)
   (lib "vector-lib.ss" "srfi" "43")
   (all-except (lib "contract.ss") ->)
   (rename (lib "contract.ss") ->/c ->)
   (planet "all.ss" ("wmfarr" "plt-linalg.plt" 1 5)))
  (provide make-L

   (neXt-gen (->/c ((hash-table? 'equal) f64vector? integer? f64vector?))))
  ;; this function builds the Leslie matrix
  ;; this works as of 23:32 on 8-20-2007
  (define (make-L M P a)
      (let* ((d (length M))               ;create a dxd matrix
             (L (make-matrix d d 0)))     ;of zeros
        (do ((x 0 (+ x 1))                ;start at 0
             (off-by 1 (+ off-by 1)))     ;off-diag elements
            ((= x d) L)                   ;when x = d we're done
          (matrix-set! L x 0 (*           
                              (* (list-ref M x) (list-ref a x))
                              (list-ref P 0))) ;f(x,t)
          (if (= x (- d 1))                    
              (matrix-set! L x off-by (list-ref P off-by))))))

  (define (make-L-helper life-table)
    (make-L (life-table-M life-table)
            (life-table-P life-table)
            (life-table-a life-table)))
  ;; usage: (define hash (build-L-hash struct-list struct-field)
  ;; the only remaining task is to coerce any input into a list, since
  ;; map and foreach expect proper lists
  (define (build-L-hash struct-list struct-field)
    (let ((hash (make-hash-table 'equal))
          (struct-list (if (atom? struct-list)
                            (list struct-list)
       (lambda (s)
         (let ((matrix (make-L-helper s)))
            (lambda (v)
              (hash-table-put! hash v matrix))
            (struct-field s))))

  ;; NEXT-GEN takes a hash L, a vector N and a time
  ;; t and produces the next vector
  ;; hash-table f64vector integer -> f64vector
  (define (neXt-gen L N t)
     (hash-table-get L t)))

  ;; NEXT-ACCUM takes a hash L, a vector N, a time
  ;; t0, t and produces a list of successive values of
  ;; the vector
  (define (neXt-accum L N t0 t)
    (let ((neXt-vec (neXt-gen L N t0)))
      (if (= 1 (- t0 t)) '()
          (cons neXt-vec
                (neXt-accum L neXt-vec
                            (add1 t0) t)))))

  ;; NEXT-DIFF take a hash L, a vector N and times t,t0 and produces the
  ;; stable age distribution
  ;; this function should be used with a call-with-values procedure to
  ;; produce the output "Population size:... Time to Stable Age
  ;; Distribution... Size of ..."
  ;; hash f64vector integer integer float -> f64vector integer float
  (define (neXt-diff L N t0 t tol)
    (let* ((neXt-vec (neXt-gen L N t0))
           (norm (f64vector-norm
                  (apply f64vector-sub
                          (neXt-accum L neXt-vec t0 (add1 t0)))))))
      (cond ((> t0 t) (error (format "Failure to converge")))
            ((< norm tol) (values
                           (vector-list-scale (list N))
            (else (neXt-diff L neXt-vec (add1 t0) t tol))))))

;; test:
  ;;   (define delta
  ;;   (make-life-table
  ;;    (iota 100 0 1)
  ;;    (iota 5 5 5)
  ;;    (iota 5 0.8 -0.02)
  ;;    (make-list 5 0.5)))

  ;; (define epsilon
  ;;   (make-life-table
  ;;    (iota 100 100 1)
  ;;    (iota 5 5 5)
  ;;    (iota 5 0.6 -0.002)
  ;;    (make-list 5 0.5)))
  ;;   (define peter
  ;;   (build-L-hash
  ;;    (list delta epsilon)
  ;;    life-table-gens))
  ;; (map f64vector->list
  ;;         (vector-list-scale
  ;;          (grow-pop-age-classes
  ;;           peter
  ;;           (make-f64vector 5 100)
  ;;           1 200)))

Joel J. Adamson
Clinical Research Analyst
Pediatric Psychopharmacology Research
Massachusetts General Hospital
55 Fruit St.
Boston, MA 02114
(617) 643-1432
(303) 880-3109 (mobile)

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