C ________________________________________________________ C | | C | COMPUTE THE DETERMINANT OF A FACTORED SYMMETRIC MATRIX | C | | C | INPUT: | C | | C | A --SFACT'S OUTPUT | C | | C | OUTPUT: | C | | C | SDET,E--DETERMINANT IS SDET*10.**E (E INTEGER) | C | | C | BUILTIN FUNCTIONS: ABS,ALOG10,DLOG10 | C |________________________________________________________| C FUNCTION SDET(E,A) REAL A(1),D,F,G DOUBLE PRECISION C INTEGER E,H,I,N D = A(1) IF ( ABS(D) .EQ. 1233 ) GOTO 10 WRITE(6,*) 'ERROR: MUST FACTOR WITH SFACT BEFORE', 1'COMPUTING DETERMINANT' STOP 10 E = 0 IF ( D .LT. 0. ) GOTO 80 D = 1. F = 2.**64 G = 1./F H = 64 N = A(2) I = 4 20 D = D*A(I) I = I + N N = N - 1 IF ( N .EQ. 0 ) GOTO 50 30 IF ( ABS(D) .LT. F ) GOTO 40 E = E + H D = D*G GOTO 30 40 IF ( ABS(D) .GT. G ) GOTO 20 E = E - H D = D*F GOTO 40 50 IF ( E .NE. 0 ) GOTO 60 SDET = D RETURN 60 IF ( D .EQ. 0. ) GOTO 90 C = ALOG10(ABS(D)) + E*DLOG10(2.D0) E = C C = C - E IF ( C .LE. 0.D0 ) GOTO 70 C = C - 1 E = E + 1 70 F = 10.**C IF ( D .LT. 0. ) F = -F SDET = F RETURN 80 SDET = 0. RETURN 90 E = 0 GOTO 80 END