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lines 5-80 of file: example/user/change_grid.py
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# {xrst_begin user_change_grid.py}
# {xrst_comment_ch #}
#
# Remove an Age or Time From a Smoothing
# ######################################
#
# Purpose
# *******
# This examples uses SQL commands to modify a data base.
# To be specific, it removes one of the age points from a smoothing grid.
#
# Age Table
# *********
# The :ref:`age_table-name` for this example is specified by the code
# ::
#
#     age_list = [0, 1, 20, 30, 40, 50, 60, 70, 80, 90, 100 ]
#
# Time Table
# **********
# The :ref:`time_table-name` is specified by
# ::
#
#     time_list = [ 1960, 1995 ]
#
# Parent Smoothing
# ****************
# The original parent smoothing table contains all of the age and time points.
#
# Value Prior
# ===========
# The value prior at each (age, time) pair is log-Gaussian with
# lower limit 1 ``e-2`` * *iota_mean* ,
# upper limit 1 *e* +2* ``iota_mean`` ,
# mean *iota mean* ,
# standard deviation *iota_mean* ,
# and the offset in the log transform 1 ``e-3`` * *iota_mean* .
#
# Difference Prior
# ================
# The forward difference prior at each (age, time) pair is log-Gaussian with
# no lower limit,
# no upper limit,
# mean zero,
# standard deviation 1.0 ,
# and the offset in the log transform ``1e-6`` .
#
# Change Parent Smoothing
# ***********************
# Note that the original age grid has 11 points.
# The last age point, and all the corresponding (age, time) pairs
# are removed from the smoothing grid with the following SQL commands:
# ::
#
#     UPDATE smooth SET n_age = 10 WHERE smooth_id == 0;
#     UPDATE smooth_grid SET smooth_id = WHERE smooth_id == 0 AND age_id == 10;
#
# We refer to this as the modified smoothing.
#
# Fit
# ***
# The only variables in this example are the parent rates for *iota* .
# Hence the number of variables in the :ref:`var_table-name` should be the number
# of grid points in the modified smoothing; i.e., 20.
# There is no data for this example.
# Hence the optimal fit is to have *iota* equal to *iota_mean*
# for all the (age, time) paris in the modified smoothing.
#
# Source Code
# ***********
# {xrst_literal
#     BEGIN PYTHON
#     END PYTHON
# }
#
# {xrst_end user_change_grid.py}