论文标题
插值基础的线性化 - 比较i
Linearizations for interpolation bases -- a comparison I
论文作者
论文摘要
解决非线性特征值问题$ t(λ)x = 0 $的一种策略是解决多项式特征值问题(pep)$ p(λ)x = 0 $,通过插值近似于原始问题。然后,通常通过线性化解决此PEP。关于线性化的大多数文献都假定$ p(λ)$是在单一基础上表达的,但是由于多项式近似技术,在这种情况下,$ p(λ)$以非工程学为基础表示。大多数频率使用的基础是Chebyshev,牛顿的基础和拉格朗日基础。在本文中,我们构建了一个线性化的$ P(λ)$的系列,该系列易于从$ p(λ)$的矩阵系数中构造,当该多项式在这三个基础中表达时。我们还提供特征向量的恢复公式(当$ p(λ)$是常规的)和最小基础和最小索引的恢复公式(当$ p(λ)$是单数时)。我们的最终目标是比较这些线性化的数值行为,在同一家族中(选择一个最佳),以及基于特征值在插值节点的位置的其他家族的线性化。
One strategy to solve a nonlinear eigenvalue problem $T(λ)x=0$ is to solve a polynomial eigenvalue problem (PEP) $P(λ)x=0$ that approximates the original problem through interpolation. Then, this PEP is usually solved by linearization. Most of the literature about linearizations assumes that $P(λ)$ is expressed in the monomial basis but, because of the polynomial approximation techniques, in this context, $P(λ)$ is expressed in a non-monomial basis. The bases used with most frequency are the Chebyshev basis, the Newton basis and the Lagrange basis. In this paper we construct a family of linearizations of $P(λ)$ that is easy to construct from the matrix coefficients of $P(λ)$ when this polynomial is expressed in any of those three bases. We also provide recovery formulas of eigenvectors (when $P(λ)$ is regular) and recovery formulas of minimal bases and minimal indices (when $P(λ)$ is singular). Our ultimate goal is to compare the numerical behavior of these linearizations, within the same family (to select the best one) and with the linearizations of other families based on the location of the eigenvalues with respect to the interpolation nodes.