====== Chapter 2 - Building the TOOL Code Logic ======

Open demogVer1.DMM in Documentor.

Double click on the Calculator node Population.  The Population [[trainingtutorial:documentor_tour#calculator diagram]] appears.

Double click on the Evolve Population procedure.  The Evolve Population [[trainingtutorial:documentor_tour#procedure editor dialogue]] appears.

===== Creating the code =====
1. Local Object - base[g,a]

[[trainingtutorial:create_code|Create code]] for base[g,a] consisting of the following TOOL statements:

<code>
local base[g,a]
base[g,a] = shrink (basePop[g,byr,a])
</code>

In this TOOL statement the shrink tool is being used to remove reference to extent 1 (indexed by byr) informants.

2. Local Object - mort[t,g,a]

[[trainingtutorial:create_code|Create code]] for mort[t,g,a] consisting of the following TOOL statements:

<code>
local mort[t,g,a]
mort[t,g,a] = reorder (mortality[g,t,a]; time, gender, age)
</code>

In this TOOL statement the reorder tool is being used to reorder the input object "mortality[g,t,a]" into the local object "mort[t,g,a]" since that is the shape needed later in the code.

3. Local Object - netImm[t,g,a]

[[trainingtutorial:create_code|Create code]] for netImm[t,g,a] consisting of the following TOOL statements:

<code>
local netImm[t,g,a]
netImm[t,g,a] = reorder (netImmgr[g,t,a]; time, gender, age)
</code>

In this TOOL statement the reorder tool is being used to reorder the input object "netImmgr[g,t,a]" into the object "netImm[t,g,a]" for use later in the code.

4. Local Object - fert[t,a]

<code>
local fert[t,a]
fert[t,a] = create (; dimFrom1=totPeriodFert[t], dimFrom3=mortality[g,t,a], \
   entityFrom=totPeriodFert[t])
fert[t,a] = insert (fertShr[t,ma] * totPeriodFert[t]; age->age:15)
</code>

In the first of these TOOL statements the create tool is being used to create the local object "fert[t,a]". The parameter "dimFrom1=totPeriodFert[t]" gets fert’s first dimension from the first dimension of "totPeriodFert[t]", the parameter "dimFrom3=mortality[g,t,a]" gets fert’s second dimension from the third dimension of "mortality[g,t,a]" and the parameter "entityFrom=totPeriodFert[t]" gets fert’s entity from "totPeriodFert[t]" (note: \ is the line continuation mark). At this point "fert[t,a]" is an empty object. The TOOL statement uses the insert tool to insert the product (* tool used with infix notation) of "fertShr[t,ma]" and "totPeriodFert[t]" into "fert[t,a]" starting at age 15 (determined by the parameter "age->age:15").

5. Output Object - population[g,t,a]

[[trainingtutorial:create_code|Create code]] for population[g,t,a] consisting of the following TOOL statements:

<code>
population[g,t,a] = reorder (populate (base[g,a], mort[t,g,a], \
   fert[t,a], genderShr[t]; netImmgr=netImm[t,g,a]); \
   gender, time, age)
</code>

In this TOOL statement the populate tool has been nested inside the reorder tool (controlled by "()" brackets).  The populate tool takes inputs of "base[g,a]", the base population; "mort[t,g,a]", the mortality; "fert[t,a]", the fertility and the parameter "netImmgr=netImm[t,g,a]"; indicates that net immigration is to be taken from "netImm[t,g,a]" and uses the cohort method to evolve the population. The populate tool’s normal population output would be ordered as "[t,g,a]" thus its output is then reordered using the reorder tool to be the right shape for the output object "population[g,t,a]".

Click OK to save your code.

When complete the TOOL code for the Evolve Population procedure should appear as shown:

{{trainingtutorial:procedureeditor.jpg}}