今天我们来看如上图所示的这个错误。这个错误代码为205，和我硕士时的办公室门牌号是一致的。。。不同的代号对应的错误类型可查看科学网的一篇文章，基本全部包含了所有错误（http://blog.sciencenet.cn/blog-2089193-1184256.html）。

这是由于模型中的系数与求解的目标的数量级差别太大所导致的。下图是官方给出的一个解决方案。

After LINGO generates a model, it checks all the nonzero coefficients in the model and computes the ratio of the largest to smallest coefficients.  This ratio is an indicator of how well the model is scaled.  When the ratio gets to be too high, scaling is considered to be poor, and numerical difficulties may result during the solution phase.  If the scaling ratio exceeds the value of the SCALEW parameter, LINGO will display this error message  The default value for SCALEW is 1e9.  Instead of simply increasing the SCALEW setting to eliminate error 205, we strongly suggest that you attempt to rescale the units of your model so as to reduce the largest-to-smallest coefficient ratio.

In some instances, changing the units of measure can be an easy way to improve a model’s scaling.  For instance, suppose we have a model with the following budget constraint in dollar units:

 1000000 * X + 2200000 * Y + 2900000 * Z