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有人可以告诉我这些以下两个符号之间的区别,一个是工作,另一个不是,但他们似乎对我来说是相同的。python与numpy的代码语法
def GradientDescentCostTest():
theta = numpy.array([0, 0, 0], numpy.float)
features = numpy.array([[80, 20, 0], [65, 30, 1], [70, 23, 1]], numpy.float)
values = numpy.array([20, 10, 14], numpy.float)
# This works and returns a value for cost:
sumOfSquareErrors = numpy.square(numpy.dot(features, theta) - values).sum()
cost = sumOfSquareErrors/(len(values)*2)
# This doesn't work and returns value 0.0 for cost:
cost = 1/(len(values)*2) * numpy.square(numpy.dot(features, theta) - values).sum()
return cost
print GradientDescentCostTest()
感谢
确定你能否提供足够的样本来运行你的样本(即所有未定义变量的例子) – 2015-02-23 22:13:21
我在学校学到了[BODMAS](http://en.wikipedia.org/wiki/Order_of_operations)。 – 2015-02-23 22:14:27
现在添加完整的代码示例,谢谢 – Manuel 2015-02-23 22:23:12