The Powellalgorithm searches for local minimum of an objective function for a set of linearly independent direction vectors without the knowledge of the derivatives. It is one of several algorithms classified as conjugate direction methods.
Analyst exposes several parameters for the Powell algorithm:
- Convergence tolerance for application of Brent's method for line minimization
- Metric stagnation tolerance defined as a fraction of the sum of the previous and current metric values.
- Maximum iterations for application of Brent's method for line minimization.
 M.J.D. Powell, "An efficient method for finding the minimum of a function of several variables without calculating derivatives," Compute J., vol. 7, pp. 155-162, July 1964
 William H. Press, Saul A. Teukolsky, William T. Vetterling, Brian P. Flannery, Numerical Recipes in C: the Art of Scientific Computing, 2nd edition, Cambridge Univ. Press, N.Y., 1992.
 Brent, R.P. 1973, Algorithms for Minimization without Derivatives (Eaglewood Cliffs, NJ: Prentice-Hall), Chapter 7.