tailieunhanh - Financial Applications using Excel Add-in Development in C/C++ phần 2

giải pháp và các tùy chọn không mong muốn ảnh hưởng đến các hành vi của thuật toán. Hiệu chỉnh phần , trên trang 511, nói chuyện nhiều hơn một chút về công cụ này rất mạnh mẽ. Sự phức tạp về quản lý khi các giải pháp hội tụ, | Excel Functionality 33 unwanted solutions and options that dictate the behaviour of the algorithm. Section Calibration on page 511 talks a little more about this very powerful tool. The complexities governing when solutions converge when they are unlikely to when there may be multiple solutions and to which one you are most likely to converge are beyond the scope of this book. Excel provides help for the solver via the Tools Solver. dialog s Help button. If you intend to rely on a solver for something important you either need to know that your function is very well behaved or that you understand its behaviour well enough to know when it will be reliable. EXCEL RECALCULATION LOGIC The first thing to say on this often very subtle and complex subject is that there is much more that can be said than is said here. This section attempts to provide some basic insight and a foundation for further reading. Excel recalculates by creating lists of cells which determine the order in which things should be calculated. Excel constructs these by inspecting the formulae in cells to determine their precedents establishing precedent dependent relationships for all cells. Once constructed cells in the lists thus generated are marked for recalculation whenever a precedent cell has either changed or has itself been marked for recalculation. Once this is done Excel recalculates these cells in the order determined by the list. After an edit to one or more formulae lists may need to be reconstructed. However most of the time edits are made to static cells that do not contain formulae and are not therefore dependent on anything. This means that Excel does not usually have to do this work whenever there is new input. As this section shows this system is not infallible. Care must be taken in certain circumstances and certain practices should be avoided altogether. VB code and spreadsheet examples are contained in the spreadsheet on the CD ROM. Further more .