Sources Esope | Cast3M

nrqfun
C NRQFUN    SOURCE    CHAT      05/01/13    02:01:54     5004
c
             FUNCTION NR_QFUNC(QINI,QA,M,CT,PRECIS)
      IMPLICIT INTEGER(I-N)
      real*8 qini,qa,m,ct,precis,qqa,valor,dq,NR_qfunc
      integer it
      valor=qini
      it=0
10    continue
      it=it+1
      qqa=(1.D0+valor/qa)
      dq=(valor*qqa**m-ct)/(qqa**m+m*valor/qa*qqa**(m-1.D0))
      valor=valor-dq
      if (abs(dq).lt.precis*(qini+1.D0)) then
         NR_qfunc=valor
         return
      endif
      if (it.gt.20) then
        write(*,*)' NR_qfunc error',it,abs(dq),precis
        stop
      endif
      goto 10
      end