%%HP: T(3)A(D)F(.);
\<< \-> matr
  \<<
    IF 'matr' VTYPE
3 == matr SIZE SIZE
1 > AND
    THEN 1 1 1 matr
SIZE LIST\-> DROP \->
det p q m n
      \<<
        WHILE 'p\<=m'
\->NUM 'q\<=n' \->NUM AND
        REPEAT 0 p
\-> cmax k
          \<< p m
            FOR row
matr row q 2 \->LIST
GET ABS \-> x
              \<<
IF 'x>cmax'
THEN x 'cmax' STO
row 'k' STO
END
              \>>
            NEXT
            IF '
cmax>.00001'
            THEN 1
n
              FOR
col matr p col 2
\->LIST GET matr k
col 2 \->LIST GET \->
tp tk
\<< matr k col 2
\->LIST tp PUT 'matr'
STO matr p col 2
\->LIST tk PUT 'matr'
STO
\>>
              NEXT
              IF 'k
>p'
              THEN
det NEG 'det' STO
              END
matr p q 2 \->LIST
GET \-> l
              \<< 1 n
FOR col matr p col
2 \->LIST GET l / \->
tl
  \<< matr p col 2
\->LIST tl PUT 'matr'
STO
  \>>
NEXT l det * 'det'
STO
              \>> 1 m
              FOR
row matr row q 2
\->LIST GET \-> l
\<< 1 n
  FOR col
    IF 'row\=/p'
    THEN matr row
col 2 \->LIST GET
matr p col 2 \->LIST
GET l * - \-> tv
      \<< matr row
col 2 \->LIST tv PUT
'matr' STO
      \>>
    END
  NEXT
\>>
              NEXT
'p' INCR DROP 'q'
INCR DROP
            ELSE 0
'det' STO 'q' INCR
DROP
            END
          \>>
        END
      \>> matr
"Reduced Echelon Matrix
 "
1 DISP 1 FREEZE
    ELSE matr
"ECHEL Error:
Not A Matrix"
1 DISP 1400 .065
BEEP 1 FREEZE
    END
  \>>
\>>