C PGCD 10
C ..................................................................PGCD 20
C PGCD 30
C SUBROUTINE PGCD PGCD 40
C PGCD 50
C PURPOSE PGCD 60
C DETERMINE GREATEST COMMON DIVISOR OF TWO POLYNOMIALS PGCD 70
C PGCD 80
C USAGE PGCD 90
C CALL PGCD(X,IDIMX,Y,IDIMY,WORK,EPS,IER) PGCD 100
C PGCD 110
C DESCRIPTION OF PARAMETERS PGCD 120
C X - VECTOR OF COEFFICIENTS FOR FIRST POLYNOMIAL, PGCD 130
C ORDERED FROM SMALLEST TO LARGEST POWER PGCD 140
C IDIMX - DIMENSION OF X PGCD 150
C Y - VECTOR OF COEFFICIENTS FOR SECOND POLYNOMIAL, PGCD 160
C ORDERED FROM SMALLEST TO LARGEST POWER. PGCD 170
C THIS IS REPLACED BY GREATEST COMMON DIVISOR PGCD 180
C IDIMY - DIMENSION OF Y PGCD 190
C WORK - WORKING STORAGE ARRAY PGCD 200
C EPS - TOLERANCE VALUE BELOW WHICH COEFFICIENT IS PGCD 210
C ELIMINATED DURING NORMALIZATION PGCD 220
C IER - RESULTANT ERROR CODE WHERE PGCD 230
C IER=0 NO ERROR PGCD 240
C IER=1 X OR Y IS ZERO POLYNOMIAL PGCD 250
C PGCD 260
C REMARKS PGCD 270
C IDIMX MUST BE GREATER THAN IDIMY PGCD 280
C IDIMY=1 ON RETURN MEANS X AND Y ARE PRIME, THE GCD IS A PGCD 290
C CONSTANT. IDIMX IS DESTROYED DURING COMPUTATION. PGCD 300
C PGCD 310
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED PGCD 320
C PDIV PGCD 330
C PNORM PGCD 340
C PGCD 350
C METHOD PGCD 360
C GREATEST COMMON DIVISOR OF TWO POLYNOMIALS X AND Y IS PGCD 370
C DETERMINED BY MEANS OF EUCLIDEAN ALGORITHM. COEFFICIENT PGCD 380
C VECTORS X AND Y ARE DESTROYED AND GREATEST COMMON PGCD 390
C DIVISOR IS GENERATED IN Y. PGCD 400
C PGCD 410
C ..................................................................PGCD 420
C PGCD 430
SUBROUTINE PGCD(X,IDIMX,Y,IDIMY,WORK,EPS,IER) PGCD 440
DIMENSION X(1),Y(1),WORK(1) PGCD 450
C PGCD 460
C DIMENSION REQUIRED FOR VECTOR NAMED WORK IS IDIMX-IDIMY+1 PGCD 470
C PGCD 480
1 CALL PDIV(WORK,NDIM,X,IDIMX,Y,IDIMY,EPS,IER) PGCD 490
IF(IER) 5,2,5 PGCD 500
2 IF(IDIMX) 5,5,3 PGCD 510
C PGCD 520
C INTERCHANGE X AND Y PGCD 530
C PGCD 540
3 DO 4 J=1,IDIMY PGCD 550
WORK(1)=X(J) PGCD 560
X(J)=Y(J) PGCD 570
4 Y(J)=WORK(1) PGCD 580
NDIM=IDIMX PGCD 590
IDIMX=IDIMY PGCD 600
IDIMY=NDIM PGCD 610
GO TO 1 PGCD 620
5 RETURN PGCD 630
END PGCD 640