File: NONLIN.FT of Tape: Various/ETH/eth11-1

(Source file text) 

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C	NONLIN.FOR - SAMPLE PROGRAM (SOLN. OF F(X)=X OR 0) :
C  RTWI		- WEGSTEIN'S ITERATION
C  RTNI		- NEWTON'S ITERATION
C  RTMI		- MUELLER'S ITERATION
	EXTERNAL FCN
	EXTERNAL FCN2
	EXTERNAL FCN3
C
C  OUTPUT CHANNEL = IOUT
	IOUT=2
	CALL RTMI(XM,FM,FCN2,0.5,1.8,1.E-3,50,IRM)
	CALL RTNI(XN,FN,DERN,FCN3,1.3,1.E-3,50,IRN)
	CALL RTWI(XW,XWF,FCN,1.15,1.E-3,50,IRW)
	WRITE(IOUT,100) XM,FM,IRM
100	FORMAT(//' SOLUTION TO X**9-1=0 NEAR 1'//
	1' MUELLER''S ITERATION'/' ROOT =',F10.5,'  FUNCTION ='
	2F10.5,/' IER =',I2)
	WRITE(IOUT,101) XN,FN,IRN
101	FORMAT(//' NEWTON''S ITERATION'/' ROOT =',F10.5,' FUNCTION ='
	1F10.5,/' IER=',I2)
	WRITE(IOUT,102) XW,XWF,IRW
102	FORMAT(//' WEGSTEIN''S ITERATION'/' ROOT =',F10.5,' X-F(X) ='
	1F10.5,/' IER=',I2)
	STOP
	END
	FUNCTION FCN(X)
C	FUNCTION FOR ROUTINE RTWI
	FCN=X**9+X-1.0
	RETURN
	END
	FUNCTION FCN2(X)
C	FUNCTION FOR ROUTINE RTMI
	FCN2=X**9-1.0
	RETURN
	END
	SUBROUTINE FCN3(X,F,DERF)
C	SUBROUTINE FOR ROUTINE RTNI
	F=X**9-1.0
	DERF=9.0*X**8
	RETURN
	END

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