我知道我以前问过同样的问题,但由于我是新来的,这个问题问得不好而且不可重现。因此我在这里尝试做得更好。 (如果我只编辑旧的,可能没有人会读它)
我有一个想要积分的二重积分:
ff<-function(g,t) exp((16)*g)*exp(-8*t-(-t-0.01458757)^2/(0.0001126501))
integrate(Vectorize(function(t) integrate(function(g)
ff(g,t), -2.5,0)$value), -2, 2)
在 R 中运行此命令会出现错误:
the integral is probably divergent
当我尝试在 Wolfram 中运行 sam 函数时,它给了我一个正确的值:(我必须切换 g=x 和 t=y)
Link:
http://www.wolframalpha.com/input/?i=integration+[%2F%2Fmath%3Aexp%28%2816%29*x%29*exp%28-8*y-%28-y-0.01458757%29 ^2%2F%280.0001126501%29%29%2F%2F]+[%2F%2Fmath%3Adx+dy%2F%2F]+for+x+from+[%2F%2Fmath%3A-2.5%2F%2F] +到+[%2F%2Fmath%3A0%2F%2F]+for+y+from+[%2F%2Fmath%3A-2%2F%2F]+到+[%2F%2Fmath%3A2%2F%2F] http://www.wolframalpha.com/input/?i=integration+%5B%2F%2Fmath%3Aexp%28%2816%29*x%29*exp%28-8*y-%28-y-0.01458757%29%5E2%2F%280.0001126501%29%29%2F%2F%5D+%5B%2F%2Fmath%3Adx+dy%2F%2F%5D+for+x+from+%5B%2F%2Fmath%3A-2.5%2F%2F%5D+to+%5B%2F%2Fmath%3A0%2F%2F%5D+for+y+from+%5B%2F%2Fmath%3A-2%2F%2F%5D+to+%5B%2F%2Fmath%3A2%2F%2F%5D
正如你所看到的,它得到了有限的结果,有人可以帮助我吗?
我在定义的区域上绘制了函数,但找不到奇点问题。看:
library('Plot3D')
x <- seq(-2.5,0, by = 0.01) #to see the peak change to: seq(-0.2,0, by = 0.001)
y <- seq(-2,2, by = 0.01) #"": seq(-0.1,0.1, by = 0.001)
grid <- mesh(x,y)
z <- with(grid,exp((16)*x)*
exp(-8*y-(-0.013615734-y-0.001+0.5*0.007505^2*1)^2/(2*0.007505^2)))
persp3D(z = z, x = x, y = y)
感谢您的帮助,我希望这个问题比旧问题结构更好。