NONMEM Tips-n-Tricks

Published

October 23, 2025

CautionUnder construction

Introduction

NONMEM is a computer program. The name stands for “NONlinear Mixed Effects Modeling.”

https://www.iconplc.com/solutions/technologies/nonmem

Some gotchas for NONMEM:

  • Machine (double) precision: MEPS = 1.0E-15
  • INFTY = 1.0E+154
  • Largest possible integer = 2147483647

Running NONMEM

  • NONMEM places the low bound equal to 1/100 (or 1/1000) of the initial value even if it is set to zero in the code. You may rerun with lower initial value or put NOTHETABOUNDTEST to the estimation record. (Credit: Leonid Gibiansky)

Faster parallel NONMEM

--threads-per-core=1: Do not hyperthread.
FILE07–39 should be size 0; in fact, FILE* should be size 0. Therefore, use --maxlim=3: Do not use diskspace (slow).

execute -nmfe_options="[sbatchargs=--threads-per-core=1] -maxlim=3  -parafprint=100"

Interactive control of NONMEM runs

Find the directory where NONMEM is running (NM_run1/ in PsN) and manually create an empty file with a different name according to the desired action.

touch file.sig

Here’s a list:

Table 1: Interactive control
Action Description Filename
Print toggle Monitor estimation progress print.sig
Paraprint toggle Monitor parallel processing traffic paraprint.sig
Next Move on to next estimation mode or next estimation. NONMEM grinds a couple of iterations more and then it terminates nicely as if the maximum number of function evaluations had been reached. next.sig
Stop End the present run cleanly stop.sig
Subject print toggle subject.sig

(Credit: Paolo Denti)

References