求助:关于SAS的数值精度

shiyiming · 发表于 2004-4-18 18:05:50

我做计算用到500**500,SAS无法计算了
我知道MATHMATIC可以轻松计算700**2000,不知道SAS的数值范围有多大,及如何调整精度,多谢了

shiyiming · 发表于 2004-4-19 21:45:09

I think your question has nothing to do with accuracy, it is overflow in floating point representation in numerical analysis. I really doubt that MATHMATICA can handle 700**2000, the number may well beyond the number of the nuclei in this universerse. If you really need to handle this kind of case, you have to take a Logarithm and transform your model. In fact, the direct attack on a number in this range generally mean nothing.

shiyiming · 发表于 2004-4-20 23:33:43

多谢xic,确实是超过了浮点数的存储范围了,要算这个只能另寻它法了 <img src="{SMILIES_PATH}/icon_confused.gif" alt=":?" title="Confused" />

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