#|;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
HW4 #6 A
DisplayMatrixRowCol.rkt by Ryan Liszewski
Reads matrix from a file and display a specified row or column
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#lang racket
;read matrix from file
(define (read-matrix filename)
  (let* ((inport (open-input-file filename))
         (nrow (read inport))
         (ncol (read inport))
         (mat (make-vector nrow)))
    (do ((i 0 (add1 i)))
      ((>= i nrow) (close-input-port inport) mat)
      (let ((row (make-vector ncol)))
        (do ((j 0 (add1 j)))
          ((>= j ncol) (vector-set! mat i row))
          (vector-set! row j (read inport)))))))

;display vector
(define (display-vector v)
  (do ((i 0 (add1 i)))
    ((>= i (vector-length v)) (display ""))
    (display (vector-ref v i)) (display " ")))

;return i-th row
(define (ro filename i)
  (define mat (read-matrix filename))
  (vector-ref mat i))
;display i-th row
(define (row filename i)
  (display-vector (ro filename (- i 1))))

;return j-th col
(define (co filename j)
  (define mat (read-matrix filename))
  (define nrow (vector-length mat))
  (define column (make-vector nrow))
  (do ((i 0 (add1 i)))
    ((>= i nrow) column)
    (vector-set! column i (vector-ref (vector-ref mat i) j))))

;display j-th col
(define (col filename j)
  (display-vector (co filename (- j 1))))







#|;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
HW4 #6 B
MatrixMultiplication.rkt by Ryan Liszewski

Multiplies two matrices from two input files and produces the result in an output file
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;|#
#lang racket
;read matrix from file
(define (read-matrix filename)
  (let* ((inport (open-input-file filename))
         (nrow (read inport))
         (ncol (read inport))
         (mat (make-vector nrow)))
    (do ((i 0 (add1 i)))
      ((>= i nrow) (close-input-port inport) mat)
      (let ((row (make-vector ncol)))
        (do ((j 0 (add1 j)))
          ((>= j ncol) (vector-set! mat i row))
          (vector-set! row j (read inport)))))))

;display components of the given vector
(define (display-vector v)
  (do ((i 0 (add1 i)))
    ((>= i (vector-length v)) (display ""))
    (display (vector-ref v i)) (display " ")))

;return i-th row
(define (ro filename i)
  (define mat (read-matrix filename))
  (vector-ref mat i))

;display i-th row
(define (row filename i)
  (display-vector (ro filename (- i 1))))

;return j-th col
(define (co filename j)
  (define mat (read-matrix filename))
  (define nrow (vector-length mat))
  (define column (make-vector nrow))
  (do ((i 0 (add1 i)))
    ((>= i nrow) column)
    (vector-set! column i (vector-ref (vector-ref mat i) j))))

;display j-th col
(define (col filename j)
  (display-vector (co filename (- j 1))))

;return dot product
(define (dot-product v1 v2)
  (do ((i 0 (add1 i)) (sum 0 (+ sum (* (vector-ref v1 i)
                                       (vector-ref v2 i)))))
    ((>= i (vector-length v1)) sum)))

;matrix multiplication
(define (mmul f1 f2 f3)
  (define m1 (read-matrix f1))
  (define m2 (read-matrix f2))
  (define nrow (vector-length m1))
  (define ncol (vector-length m2))
  (define outport (open-output-file f3))
  (display nrow outport) (display " " outport)
  (display ncol outport) (newline outport)
  (do ((i 0 (add1 i)))
    ((>= i nrow) (close-output-port outport) (display ""))
    (let ((row (make-vector ncol)))
      (do ((j 0 (add1 j)))
        ((>= j ncol) (display-vector row) (newline) (newline outport))
        (vector-set! row j (dot-product (ro f1 i) (co f2 j)))
        (display (vector-ref row j) outport) (display " \n" outport)))))