casperyc

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14 years, 246 days
University of Kent
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These are questions asked by casperyc

Hi,

I have coded up a vector that is of my interest. The code runs witout any problem and gives me exactly what I want.

newtest.mw

All I want to know, is that if there are more efficient way to do so?

Any tricks, or better use of a particular function that I wasn't aware?

The only tiny bit of unsatisfactory is that, the (1-w) term is at the first term of the addition, is that possible to move it to the last term? Which is more conventional to read.

 

Thanks,

 

casper

kappa := Vector(7, [1,w[1]*(1-phi+phi*(1-1/(1+exp(-mu[p]-tau[p3]))))+(1-w[1])*
(1-phi+phi*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2])))),w[1]*phi/(1+exp(-mu[p]-tau[
p3]))+(1-w[1])*phi/(1+exp(-mu[p]-tau[p3]-eta[p2])),w[1]*(1-phi+phi*(1-1/(1+exp
(-mu[p])))*(1-phi)+phi^2*(1-1/(1+exp(-mu[p])))*(1-1/(1+exp(-mu[p]-tau[p3]))))+
(1-w[1])*(1-phi+phi*(1-1/(1+exp(-mu[p]-eta[p2])))*(1-phi)+phi^2*(1-1/(1+exp(-
mu[p]-eta[p2])))*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2])))),w[1]*phi^2*(1-1/(1+exp
(-mu[p])))/(1+exp(-mu[p]-tau[p3]))+(1-w[1])*phi^2*(1-1/(1+exp(-mu[p]-eta[p2]))
)/(1+exp(-mu[p]-tau[p3]-eta[p2])),w[1]*(phi/(1+exp(-mu[p]))*(1-phi)+phi^2/(1+
exp(-mu[p]))*(1-1/(1+exp(-mu[p]-tau[p3]))))+(1-w[1])*(phi/(1+exp(-mu[p]-eta[p2
]))*(1-phi)+phi^2/(1+exp(-mu[p]-eta[p2]))*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2]))
)),w[1]*phi^2/(1+exp(-mu[p]))/(1+exp(-mu[p]-tau[p3]))+(1-w[1])*phi^2/(1+exp(-
mu[p]-eta[p2]))/(1+exp(-mu[p]-tau[p3]-eta[p2]))]);

Download kappa.txt

Here is the expression, I am trying to simplify, given a set of rules. NEW_Cole.mw

I have tried different substitutions, using simplify with side rules, applyrule, eval, subs, algsubs.

But none seem to be working as the way I want them to be.

 

Is there a better way?

 

Thanks!

Hi,

I was helping for a computing session today.

Maple 17 and 18 were not plotting the following:

 

restart:

with(plots):
spacecurve([x,cos(x), sin(x)], x = 0..10);

On some of the machines, with campus site license, windows 7, x64.

The plot came up with a "frame" only. And nothing was plotted.

We really can't figure out why?

Something to do with the settings(options)?

 

Had anyone had a similar experience?

 

Thanks,

 

casper

See AAAA.mw

The alpha and beta are 'randomly' chosen, both >0, to produce some values, hence a value for the target function to optimize.

I am having trouble to evaluate the expression in the middle of the calculation.

Sometimes, the 'chosen' alpha and beta works fine with 'method = _d01amc' for numerical integration. and such way is really "fast".

 

But sometimes, the the 'chosen' alpha and beta will fail. Even when both of them are perfectly defined. and the integral can be easily evaluated using Int() and then evalf().

 

So what's be best way to proceed?

Thanks,

casperyc

If I were to evaluate a single numerical integral, I can use evalf( Int(,method = _d01amc)).

But when the expression say is created by a built in function, Student[VectorCalculus][Hessian], from a complicated expression involve integrals. The resulting expression does not have the option "method = _d01amc". It then takes a long time to evaluate.

See this "HE" variable for example. HE.txt

value(HE); # takes a long time

evalf(HE); # takes a long time

 

Is there a way to evaluate "HE", using ",method = _d01amc" wherever necessary?

 

Thanks!

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