228 DO 114 IS = 1,3 



229 SLOP = SLOP + W(IS + 4) * T(IS) 



230 SLOPI = SLOPI + WI(IS+4) ♦ T(IS) 



231 SUM = SUM + W(IS) * T(IS) 



232 114 SUMI = SUMI + WI(IS) * T(IS) 



233 V = SUM 



234 VI = SUMI 



235 CALL SETUP 



236 CALL DETNT (N,DET,DETI) 



237 C** EVALUATE DETERMINANT AT THE EXTRAPOLATED POINT. 



238 VEL = DET 

 233 VELI = DETI 



240 C** ITERATE FOR THE ROOT USING EXTRAPOLATED SLOPE. 



241 DELTA = DET * SLOP - DETI * SLOPI 



242 DELTI = DET * SLOPI + DETI * SLOP 



243 IF (K1 .EO. 1) PRINT 1330, V, VI, DET, DETI, DELTA, DELTI 



244 V = V + DELTA 



245 VI = VI + DELTI 



246 IF (VI .GE. 0.) GO TO 124 



247 DELTI = DELTI - VI 



248 CHNGI = CHNGI - VI 



249 VI = 0. 



250 C** RE-EVALUATE AT NEW POINT. 



251 124 CALL SETUP 



252 CALL DETNT (N, DET, DETI) 



253 TEMNR = DELTA 



254 TEMNI = DELTI 



255 TEMDR=VEL-DET 



256 TEIV!DI=VELI-DETI 



257 TEMDEN=TEMDRf TEMDR+TEMDI*TEMDI 



258 IF (TEMDEN .EO. 0.) GO TO 123 



259 TEMRNU=TEMNR*TEMDR+TEMNI*TEMDI 

 2C0 lcKUNU=TEMNI^TEMDR-TEMNR*TEMDI 



261 C** EVALUATE SLOPE (RECIPROCAL ACTUALLY USED). 



262 SLR = TEMRNU / TEMDEN 



263 SLI = TEMINU / TEMDEN 



264 DELTA = DET * SLR - DETI * SLI 



265 DELTI = DET * SLI + DETI * SLR 



266 IF (K1 .EO. 1) PRINT 1330, V, VI, DET, DETI, DELTA, DELTI 



267 C** CORRECT PHASE VELOCITY TO BEST VALUE. 



268 V = V + DELTA 



269 VI = VI + DELTI 



270 TEMP = V**2 / (TEMNR**2 + TEMNI**2) 



271 C** WAS INCREMENT LARGE ENOUGH TO PERMIT EVALUATION OF SLOPE. 



272 IF (TEMP . LT . RLIM) GO TO 123 



273 IF (TEMP . LT . 1.E34) GO TO 141 



274 SLR = SLOP 



275 C** IF NOT, USE EXTRAPOLATED SLOPE. 



276 SLI = SLOPI 



277 GO TO 141 



278 123 CONTINUE 



279 C** IF SO, FIND 1 - RATIO OF SLOPES. 



280 TEMDEN = ft;iR**2 + SLI**2) 



281 TEMDR = SLR * SLOP + SLI * SLOPI - TEMDEN 



282 TEMDI = SLR * SLOPI - SLI * SLOP 



283 TEMP = (TEMDR*+2 + TEMDI**2) / TEMDEN**2 



284 IF (TEMP .GT. TLIM) GO TO 116 



98 



