Message-ID: <2475A5E7ACB80F4C81BFF348ADCC9B0F4E635EDD@EXMBX03.xuhb.nhs.uk>
Date: 2016-04-26T12:25:19Z
From: David Mcnulty
Subject: Penalised spline regression
Good Afternoon Everyone,
I am looking for advice fitting a linear mixed model where the random components do not seem to fit within the model formulae for lmer. The columns of Z are not stratified and have the notional random formula (z1 | 1) + ... + (zk | 1).
Context
I am fitting a penalised thin plate spline with knots k1 to kn. The basis functions Zk are |x-ki|^3 and the penalty matrix has elements |ki-kj|^3. Rather than fit basis functions Zk I have transformed the basis to Z = Zk %*% penalty^(-1/2).
Full details are in section 2: Bayesian analysis for penalised spline regression using winBUGS. https://www.jstatsoft.org/article/view/v014i14/v14i14.pdf
I am specifically looking for an alternative to the function spm() in package semipar.
Thank you for any help or advice.
Dave.
David Mcnulty
Medical Statistician
Tel: +44 (0) 121 371 2448
Internal: 12448
Email: David.Mcnulty at uhb.nhs.uk
Web: http://www.uhb.nhs.uk
Health Informatics - University Hospitals Birmingham NHS Foundation Trust
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