The Matrix Unwinding Function
Talk by Mary Aprahamian
Date: 18.11.14 Time: 17.00 - 18.00 Room: ETH HG G 43
In this talk we introduce the matrix unwinding function, which describes the discrepancy between a matrix and the principal logarithm of its exponential. We show that the unwinding function is instrumental in the derivation of correct identities involving logarithms and facilitates the understanding of other complex multivalued matrix functions, including inverse trigonometric functions. We also use it to study the matrix sign function. We give a numerical scheme for computing the matrix unwinding function and show how it can be used in conjunction with the scaling and squaring algorithm to compute the matrix exponential using the idea of argument reduction. (Joint work with Nick Higham)