Define relationship between parameters and covariates
Expression property is a character vector
or cell array of character vectors, where each character vector represents
the relationship between a parameter and one or more covariates. The
denotes fixed effects with the prefix
random effects with the prefix
Each expression must be in the form:
This example of an expression defines the relationship between
a parameter (
volume) and a covariate (
with fixed effects, but no random effects:
This table illustrates expression formats for some common parameter-covariate relationships.
|Parameter-Covariate Relationship||Expression Format|
|Linear with random effect|
|Exponential without random effect|
|Exponential, WEIGHT centered by mean, has random effect|
|Exponential, log(WEIGHT), which is equivalent to power model|
|Exponential, dependent on WEIGHT and AGE, has random effect|
|Inverse of probit, dependent on WEIGHT and AGE, has random effect|
|Inverse of logit, dependent on WEIGHT and AGE, has random effect|
To simultaneously fit data from multiple dose levels, use a
as an input argument to
and omit the random effect (
eta) from the
Expression property must meet the following
The expressions are valid MATLAB® code.
Each expression is linear with a transformation.
There is exactly one expression for each parameter.
In each expression, a covariate is used in at most one term.
In each expression, there is at most one random effect (
Fixed effect (
theta) and random effect (
eta) names are unique within and across expressions. That is, each covariate has its own fixed effect.
to view the covariate data when writing equations for the
to check that the
Expression property of a
meets the conditions described previously.
|Applies to||Object: |
|Data type||Character vector or cell array of character vectors|