209 reputation
17
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location London, United Kingdom
age 46
visits member for 3 years
seen Jan 24 at 17:31

Oct
15
awarded  Popular Question
Feb
20
revised Numerical approximation of Levy Flight
Added Matlab code
Feb
12
comment Numerical approximation of Levy Flight
Hi @Asad Ali: the power law distribution is used to control the length of each step (always positive), but each step is in a random direction (see second paragraph in my question above), which produces a 2-d path. I will try to find some matlab code for you (but it might take a day or so!).
Jul
21
awarded  Yearling
Sep
22
accepted normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
Sep
22
awarded  Commentator
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
let us continue this discussion in chat
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
Brain and laptop both about to run out of batteries... thanks for your help anon - I'll have to try to work out the rest tomorrow.
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
I'm getting something like $(x^{-2},y^{-2},1)$...
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
@anon: um, $z+(x^2+y^2)^{-1/2}=0$, but it may take me several days to differentiate it... :)
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
Is it $\nabla F(a)=(\frac{\partial F}{\partial x},\frac{\partial F}{\partial y},\frac{\partial F}{\partial z})$?
Sep
22
comment normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
Ok, but how do I work out $\nabla F(a)$? Sorry, my maths is very rusty...
Sep
22
asked normal vector to surface $z=\frac{-1}{\sqrt{x^2+y^2}}$
Sep
13
accepted Name for $(1-x)$?
Sep
13
accepted Fitting an exponential function to data
Sep
13
awarded  Nice Question
Sep
12
comment Name for $(1-x)$?
@Rasmus: ...and what's the word to describe that property?
Sep
12
comment Name for $(1-x)$?
@Americo: Ah yes, thank you. (Happy to accept if you make it an answer...)
Sep
12
asked Name for $(1-x)$?
Sep
3
comment Fitting an exponential function to data
Thanks for this, I hadn't come across lsqnonlin() before... I'll see if I can make it work.