NUMERICAL METHOD IV - Interpolation and Shape Functions

An excellent textbook established at several universities. Primarily written for students at technical universities, it is also a very useful handbook for engineers, PhD students and scientists. Now available in several forms at all continents. This textbook introduces the reader into various interpolation methods. The interpolation domain is usually divided into interpolation elements, such as finite elements and boundary elements. Interpolation on these elements is provided by shape functions, which are systematically defined in global and local coordinates by using null-points, null-lines or null-planes. Why the interpolation and shape functions are so important? Simply, because various various numerical methods (such as FEM and BEM) are based on them. The book is divided into seven chapters. The first chapter briefly explaines a background of interpolation. There is explained a difference between simple interpolation methods and higher level interpolation methods, as well as two kinds of interpolation formulas which uses coordinate and shape functions. In the second chapter are described various polynomial interpolation methods. It is also shown how Chebyshev polynomial interpolation my suppress Runge’s phenomenon and reduce interpolation error. In the third chapter non-polynomial methods (exponential, logarithmic, and rational) are discussed. These methods are important if the interpolation is performed over the semi-infinite or infinite domain, while described Fourier interpolations should be used if the interpolation function is periodic. Piecewise interpolation with one dimensional interpolation elements and splines are described in the fourth chapter. Interpolation on triangular and rectangular elements, as well as construction of their shape functions are described in the fifth and sixth chapter. Finally, volume interpolation elements (tetrahedral, prismatic and cube elements) are described in seventh chapter. Practical application is supported by 10 algorithms and 43 examples. Described interpolation elements can be easily used in finite and boundary element methods. Besides its practical usage, the given text with 131 figures and 26 tables, represents a valuable background for understanding, developing and applying various numerical methods.