Forrester and others built models of the world economy that launched the discipline of highly abstracted simulations as a worthwhile endeavor. As we explore the potential of our own modular modeling approach we join the gaggle of World implementors. wikipedia 
This javascript implementor cautions, any serious investigation of the World3 model should be done with one of the more reliable simulation packages, such as Stella II or Vensim. post source enlarge
http://ward.dojo.fed.wiki/assets/pages/world-modeled/ltg.html HEIGHT 350
Click run to begin.
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The program consists of 2000 lines of javascript organized as six object types instantiated in five sectors, sometimes divided into subsectors.
cat ltg.js | egrep '// const'
// constructor for Level objects // constructor for Rate objects // constructor for Aux objects // constructor for Smooth objects // constructor for Delay3 objects // constructor for Table objects
cat ltg.js | egrep 'SECTOR|Subsector'
// THE POPULATION SECTOR // The Death-Rate Subsector // The Birth-Rate Subsector // THE CAPITAL SECTOR // The Industrial Subsector // The Service Subsector // The Jobs Subsector // THE AGRICULTURAL SECTOR // NONRENEWABLE RESOURCE SECTOR // PERSISTENT POLLUTION SECTOR
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InsightMaker has a World3 model adapted from that in Modelica. We extract 4000 lines of xml, convert it to json, and query out features. pdf github
cat insight.json |\ jq '.mxGraphModel.root.Stock[]._name'
"Service Capital" "Persistent Pollution" "Persistent Pollution Tech" "Natural Resources" "Res Tech" "Land Fertility" "Yield Tech" "Labor Utilization Fraction Del" "Industrial Capital" "Agriculture Inputs" "Perceived Food Ratio" "Arable Land" "Potentially Arable Land" "Urban Industrial Land" "Population 0 14" "Population 15 44" "Population 45 64" "Population 65 plus"
cat insight.json |\ jq '.mxGraphModel.root.Flow[]._name'
"Service Capital Investment" "Service Capital Deprecation" "Persistent Pollution Appear Rate" "Persistent Pollution Assimilation Rate" "Persistent Pollution Tech Change Rate" "Natural Resources Use Rate" "Res Tech Change Rate" "Land Fertility Regeneration" "Land Fertility Degradation" "Yield Tech Change Rate" "Change Labor Utilization Fraction Del" "Industrial Capital Investment" "Industrial Capital Deprecation" "Change Agriculture Inputs" "Change Perception Food Ratio" "Land Removal for Urban Industrial Use" "Erosion" "Land Development Rate" "Births" "Mature 14" "Mature 44" "Mature 64" "Deaths 65p" "Deaths 0 14" "Deaths 15 44" "Deaths 45 64"
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The System Dynamics Library with World Dynamics in Modelica by Francois Cellier et al after the original World3 model. post
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Maybe we describe input-output relationships graphically and then solve for input. See Solve for Initial Conditions