Comparison of optimization and programmatic languages for global food and water models: Effects on model implementation and results.

摘要

Global food and water models can be used in multi-objective planning of water resources to increase food production.; The International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) is a global agro-economic simulation model that provides 30-year forecasts of food production, demand, and trade under different socio-economic and agricultural scenarios. The model was translated from the General Algebraic Modeling System (GAMS) to Visual Basic (VB). Comparisons of the two versions revealed programming implementation was easier and run-times were faster in GAMS due to the language's set capabilities, but data management and distribution was easier in VB because of its compatibility with other software packages.; The Water Simulation Model (WSM) is a global multi-reservoir optimization model that predicts irrigation water availability, which can be used as input to the IMPACT model, for 69 global basins. This model was also translated from GAMS to VB, and results similar to the IMPACT model were obtained. An evolutionary solver was introduced to WSM, but was not able to produce a satisfactory result.; An inquiry into the impact of objective function definition in WSM revealed that careful definition of the objective function is important, as model results indicated a high, rather regionally-consistent, level of sensitivity to the definition. An explicit statement of the objective function used to obtain a set of model results should be included in the discussion to better facilitate comparison between model runs. (Abstract shortened by UMI.)