pca_matlab

进行PQ分解，计算电力系统潮流的有效方法，应用广泛(PQ decomposition is an effective method for calculating power flow in power system.)

说明：   这是几个常用的测试函数，通过这个测试函数可以比较算法性能的优劣。(This is a test of several commonly used functions, through this test function can compare the algorithm performance is good or bad.)

说明：  用fortran 70实现数值积分，并实例计算了三个函数，导出了积分值和误差(The numerical integration is realized by FORTRAN 70, and three functions are calculated with examples. The integral values and errors are derived.)

ABAQUS中用户材料子程序UMAT的开发主要解决两方面的问题：本构模型的建立和积分算法的选择。 本文主要研究非线性材料的UMAT实现方法，并重点研究其迭代算法部分，目前，用户材料子程序UMAT的迭代算法主要是常刚度法，常刚度法的优点在于算法原理较简单，程序编写较方便，缺点是当遇到复杂非线性材料时，其迭代次数较多，收敛速度也较慢，在这个情况下，本文采取的是一种迭代次数较少且收敛速度较快的切线刚度法，具体就是采用FORTRAN语言编制了基于Von-Mises模型的接口程序,并采用切线刚度算法，通过与ABAQUS自带本构关系计算的结果相比较，验证其正确性。(This paper studies the user subroutine UMAT of ABAQUS development methods, the use of FORTRAN language isotropic hardening material model of the interface program, studied the effects of such material is extremely elastic-plastic constitutive relation method. This article UMAT tightly around the secondary development of technology, the first principle of its interface detail, and then for the theory of nonlinear finite element incremental stiffness of the regular tangent stiffness method and the theory of algorithms to do an in-depth analysis of deduced a regular tangent stiffness and rigidity of the law of the specific expression of algorithm theory, and then the preparation of the two algorithms, respectively, of the UMAT program, and finally the establishment of a specific model checking, bringing with ABAQUS elasto-plastic constitutive relation of the calculated results compared to verify the correctness of the two.)

粘弹正演程序和模型实例,2维数值模拟正演，适应于粘弹介质，(This program can be two-dimensional numerical simulation of acoustic wave equation, Viscoelastic isotropic media.)

基于最小二乘法的离散数据的曲面拟合，有二次拟合和三次拟合，并能自动出图(Based on the least squares method of discrete data of the surface fitting, there are quadratic fitting and three fitting, and can automatically plot)

说明：  利用MATLAB实现了16位快速傅立叶变换，并与自包含函数进行了比较。(The 16-bit Fast Fourier Transform is realized by using MATLAB and compared with the self-contained function.)

三相潮流计算，使用的是牛顿拉弗逊方法。迭代较快。是解决潮流的较有效的方法。(Three-phase power flow calculation, using Newton' s method Laffer Johnson. Iterate rapidly. The trend is to solve the more effective method.)

最优化的bfgs算法，是采用matlab编程(BFGS optimization algorithm, using matlab programming)

别人的程序（Fortran）是关于边界元法求解声学问题。(Someone else' s program (Fortran) is on the boundary element method to solve acoustic problems.)