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lines 5-198 of file: xrst/table/var_table.xrst
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{xrst_begin var_table}

Identifying Model Variables
###########################

Discussion
**********
The ``variable`` table maps the *var_id*
to information that specifies exactly which
:ref:`model_variable<model_variables-name>` it corresponds to.
You can use this information to interpret a :ref:`fit_var_table-name`
created by the :ref:`fit_command-name` ,
or to create a :ref:`truth_var_table-name`
for use as input to the :ref:`simulate_command-name` .

var_id
******
This column has type ``integer`` and is the primary key for this table.
Its initial value is zero, and it increments by one for each row.

var_type
********
The column has type ``text`` and has one of the following possible values:

mulstd_value
============
This variable multiplies the standard deviation in the
:ref:`mulstd_value_prior<smooth_table@mulstd_value_prior_id>`
for the corresponding *smooth_id* ; see
:ref:`smoothing standard deviation multiplier<model_variables@Fixed Effects, theta@Smoothing Standard Deviation Multipliers, lambda>` .

mulstd_dage
===========
This variable multiplies the standard deviation in the
:ref:`mulstd_dage_prior<smooth_table@mulstd_dage_prior_id>`
for the corresponding *smooth_id* ; see
:ref:`smoothing standard deviation multiplier<model_variables@Fixed Effects, theta@Smoothing Standard Deviation Multipliers, lambda>` .

mulstd_dtime
============
This variable multiplies the standard deviation in the
:ref:`mulstd_dtime_prior<smooth_table@mulstd_dtime_prior_id>`
for the corresponding *smooth_id* ; see
:ref:`smoothing standard deviation multiplier<model_variables@Fixed Effects, theta@Smoothing Standard Deviation Multipliers, lambda>` .

rate
====
This variable is rate for the corresponding
*age_id* , *time_id* ,
*node_id* , and *rate_id* .
If the *node_id* is the
:ref:`parent_node_id<option_table@Parent Node>` , it is a
:ref:`fixed effect<model_variables@Fixed Effects, theta@Parent Rates>` .
Otherwise, it is a
:ref:`random effect<model_variables@Random Effects, u@Child Rate Effects>` .

mulcov_rate_value
=================
This variable corresponds to a
:ref:`group<model_variables@Fixed Effects, theta@Group Covariate Multipliers>`
or
:ref:`subgroup<model_variables@Random Effects, u@Subgroup Covariate Multipliers>`
covariate multiplier that affects the rate for the corresponding
*age_id* , *time_id* ,
*rate_id* , and *covariate_id* .

mulcov_meas_value
=================
This variable corresponds to a group or subgroup covariate multiplier
that affects the measurement value for the corresponding
*age_id* , *time_id* ,
*integrand_id* , and *covariate_id* .

mulcov_meas_noise
=================
This variable corresponds to a group covariate multiplier
that affects the measurement value
*age_id* , *time_id* ,
*integrand_id* , and *covariate_id* .
There are no subgroup covariate multipliers of this type.

smooth_id
*********
If *var_type* is
``mulstd_value`` , ``mulstd_dage`` or ``mulstd_dtime`` ,
this is the :ref:`smooth_table@smooth_id` for the
smoothing that this variable multiplies.
Otherwise, the specified smoothing is used for the priors
for this variable.
To be specific,
the corresponding priors can be found by matching
*smooth_id* , *age_id* , and *time_id* in the
:ref:`smooth_grid_table-name` .

age_id
******
If *var_type* is
``mulstd_value`` , ``mulstd_dage`` , ``mulstd_dtime`` ,
this column is ``null`` .
Otherwise this is the :ref:`age_table@age_id` that identifies
the age for the corresponding variable.

time_id
*******
If *var_type* is
``mulstd_value`` , ``mulstd_dage`` , ``mulstd_dtime`` ,
this column is ``null`` .
Otherwise this is the :ref:`time_table@time_id` that identifies
the time for the corresponding variable.
Otherwise, this column is ``null`` .

node_id
*******
If *var_type* is ``rate`` ,
this is the :ref:`node_table@node_id` that the rate is for.
Otherwise, this column is ``null`` .

rate_id
*******
If *var_type* is ``rate`` or ``mulcov_rate_value`` ,
this is the :ref:`rate_table@rate_id` for the specific rate.
Otherwise, this column is ``null`` .

integrand_id
************
If *var_type* is
``mulcov_meas_value`` or ``mulcov_meas_noise`` ,
this is the :ref:`integrand_table@integrand_id`
that this variable applies to.
Otherwise, this column is ``null`` .

covariate_id
************
If *var_type* is
``mulcov_rate_value`` , ``mulcov_meas_value``
or ``mulcov_meas_noise`` ,
this is the :ref:`covariate_table@covariate_id`
that this variable applies to.
Otherwise, this column is ``null`` .

mulcov_id
*********
If *var_type* is
``mulcov_rate_value`` , ``mulcov_meas_value``
or ``mulcov_meas_noise`` ,
this is the :ref:`mulcov_table@mulcov_id`
that this variable applies to.
Otherwise, this column is ``null`` .

group_id
********

mulcov_meas_noise
=================
If *var_type* is ``mulcov_meas_noise`` ,
*group_id* is the mulcov table
:ref:`mulcov_table@group_id`
that this fixed effect variable applies to.

mulcov_rate_value, mulcov_meas_value
====================================
If *var_type* is ``mulcov_rate_value`` or ``mulcov_meas_value`` .
In this case either *group_id* or *subgroup_id*
(but not both) is not null.
If *group_id* is not null,
it is the mulcov table
:ref:`mulcov_table@group_id`
that this fixed effect applies to.

Otherwise
=========
*group_id* must be null.

subgroup_id
***********

mulcov_rate_value, mulcov_meas_value
====================================
If *var_type* is ``mulcov_rate_value`` or ``mulcov_meas_value`` .
In this case either *group_id* or *subgroup_id*
(but not both) is not null.
If *subgroup_id* is not null,
it is the :ref:`subgroup_table@subgroup_id`
that this random effect applies to.

Otherwise
=========
*subgroup_id* must be null.

Example
*******
See the :ref:`init_command.py-name` example and test.

{xrst_end var_table}