Linear and nonlinear least squares computing in view of control applications: invited survey talk presented at the 2nd IFAC Workshop "Control Applications of Nonlinear Programming and Optimization", DFVLR Oberpfaffenhofen, Sept. 80 - Deuflhard, Peter (Preprint / Sonderforschungsbereich <123> Stochastische Mathematische Modelle, Universität Heidelberg, 1980)