The operation of the truss analysis application is detailed on the pages within the site. The binary search is used for dyanmic analyses, continually cutting the breaking-point search range in half. The Gaussion REF method is just a way of solving simultaneous equations arranged into a matrix. It works by solving each equation in terms of one varialbe at a time, and substituing the expression into the other equations. More on both these methods appears within the site files.
Memory really is the only limit to the truss analysis program supplied online.
It has been designed to expand to fit any sized truss, and can handle anything that your computer has memory for. The computations are limited by the floating point precision available. Glance through the truss after an analysis, and make sure that it makes sense. In line with the floating point precision, the number are rounded off to three sig figs. A force of 1.00023 will end up being a 1.00 on the display.