1  ! PROGRAM INVE, VERSION 1A (31-AUG-73)
   !
2  ! PROGRAM INVE PERFORMS MATRIX INVERSIONS FOR COSAP MODULES.
   ! IT IS ONE OF THE SEVERAL PROGRAMS AND FILES WHICH COMPOSE COSAP,
   ! LAWRENCE UNIVERSITY'S CONVERSATIONALLY ORIENTED STATISTICAL
3  ! ANALYSIS PACKAGE.  COSAP IS DISTRIBUTED FOR EDUCATIONAL USE, ON
   ! THE CONDITION THAT IT NOT BE SOLD, RENTED OR LEASED FOR PROFIT.
   !
4  ! IF YOU DESIRE FURTHER INFORMATION ABOUT COSAP, PLEASE CONTACT THE
   !LAWRENCE UNIVERSITY COMPUTER CENTER, APPLETON, WISCONSIN, 54911.
   !
10 DIM N%(30%) ! FUNCTION TO CREATE FILE EXT BASED ON JOB #
20 DEF FNZ$ : IF N%(0%)=30% THEN 30 
   ELSE CHANGE SYS(CHR$(6%)+CHR$(9%)+CHR$(0%)) TO N% :
   Z8$=".J"+RIGHT(NUM$(N%(1%)/2%),2%)
30 FNZ$=Z8$ ! EXTENSION IS ".J" + JOB #
40 FNEND
110 OPEN "DISC2"+FNZ$ AS FILE 2%
120 OPEN "DISC1"+FNZ$ AS FILE 3%
130 DIM #2%, N2(50%),M2(50%),T9(0%),L6(0%),G9(0%),L1(0%)
140 DIM #3%,R(50%,50%)
150 L6=L6(0%)
160 DIM L(50%),M(50%)
170 D=1
180 FOR K%=1% TO L6 : L(K%)=K% : M(K%)=K% : A6=R(K%,K%) :
    FOR I%=K% TO L6 : FOR J%=K% TO L6 : 
    IF ABS(A6)>=ABS(R(I%,J%)) THEN 200
190 A6=R(I%,J%):L(K%)=I%:M%(K%)=J%
200 NEXT J% : NEXT I%
210 J=L(K%) : IF L(K%)<=K% THEN 230
220 FOR I%=1% TO L6 : H=-R(K%,I%) : R(K%,I%)=R(J,I%) : R(J,I%)=H :
    NEXT I%
230 I%=M(K%) : IF M(K%)<=K% THEN 250
240 FOR J%=1% TO L6 : H=-R(J%,K%) : R(J%,K%)=R(J%,I%) : R(J%,I%)=H :
    NEXT J%
250 FOR I%=1% TO L6 : IF I%=K% THEN 260 ELSE R(I%,K%)=R(I%,K%)
    /(-R(K%,K%))
260 NEXT I% :  FOR I%=1% TO L6 : FOR J%=1% TO L6 : IF I%=K% THEN 280
    ELSE IF J%=K% THEN 280
270 R(I%,J%)=R(I%,K%)*R(K%,J%)+R(I%,J%)
280 NEXT J% : NEXT I% : FOR J%=1% TO L6 : IF J%=K% THEN 290 ELSE
    R(K%,J%)=R(K%,J%)/R(K%,K%)
290 NEXT J% : D=D*R(K%,K%) : R(K%,K%)=1/R(K%,K%) : NEXT K%
300 K%=L6
310 K%=K%-1%
320 IF K%<=0% THEN 500
330 I%=L(K%) : IF I%<=K% THEN 350
340 FOR J%=1% TO L6 : H=R(J%,K%) : R(J%,K%)=-R(J%,I%) : 
    R(J%,I%)=H  : NEXT J%
350 J%=M(K%) : IF J%<=K% THEN 310
360 FOR I%=1% TO L6 : H=R(K%,I%) : R(K%,I%)=-R(J%,I%) : 
    R(J%,I%)=H : NEXT I% : GOTO 310
500 CLOSE 1%,2%,3%,4%,5% : K$=SYS(CHR$(7%)) : N$=LEFT(K$,7%) :
    S0=VAL(RIGHT(K$,8%)) : CHAIN N$ S0
32767 END