settol_root - fabiankindermann/ce-fortran GitHub Wiki

subroutine settol_root(tol)

Allows to alter the tolerance level of the root-finder fzero. By default, the tolerance level is . The tolerance level is used by fzero to indicate whether a root of the non-linear equation system has been found. The subroutine thereby considers the value an (approximate) root of the system, if

• real*8 :: tol
  A scalar value indicating the new tolerance level for the root-finder fzero. Note that tol needs to be strictly greater than 0, otherwise the subroutine will throw an error message.

• For further reading refer to:
  • Broydn, C.G. (1967). Quasi-Newton methods and their application to function minimisation. Mathematics of Computation, 19, 577-593.
  • Allen, M.B. & Isaacson, E.L. (1998). Numerical Analysis for Applied Science. Wiley Series in Pure and Applied Mathematics, New York: Wiley.
• This routine is used in the following programs:
  • prog09_08.f90
  • prog09_08m.f90
  • prog09_09.f90
  • prog09_09m.f90
  • prog09_10.f90
  • prog09_10m.f90
  • prog10_04.f90
  • prog10_05.f90
  • prog10_06.f90