Add small random numbers to default initial values for rate constants to avoid

numerical artefacts occurring in eigenvalue based solutions.



git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/kinfit/pkg/mkin@135 edb9625f-4e0d-4859-8d74-9fd3b1da38cb

1 files changed, 2 insertions, 2 deletions

diff --git a/R/mkinfit.R b/R/mkinfit.R
index 635ec29..2012755 100644
--- a/R/mkinfit.R
+++ b/R/mkinfit.R
@@ -60,7 +60,7 @@ mkinfit <- function(mkinmod, observed,
   defaultpar.names <- setdiff(mkinmod$parms, names(parms.ini))

   for (parmname in defaultpar.names) {

     # Default values for rate constants, depending on the parameterisation

-    if (substr(parmname, 1, 2) == "k_") parms.ini[parmname] = 0.1 

+    if (substr(parmname, 1, 2) == "k_") parms.ini[parmname] = 0.1 + runif(1)/1e6

     # Default values for rate constants for reversible binding

     if (grepl("free_bound$", parmname)) parms.ini[parmname] = 0.1 

     if (grepl("bound_free$", parmname)) parms.ini[parmname] = 0.02

@@ -115,7 +115,7 @@ mkinfit <- function(mkinmod, observed,
       solution_type = "analytical"

     } else {

       if (is.matrix(mkinmod$coefmat)) {

-	solution_type = "eigen"

+        solution_type = "eigen"

         if (max(observed$value, na.rm = TRUE) < 0.1) {

           stop("The combination of small observed values (all < 0.1) and solution_type = eigen is error-prone")

         }