Hi all,

I want to create a (set of) samples from an own distribution. The distribution itself is a normal distribution, but with some 'gaps', as shown below:

(It is supposed to represent the distribution of discrete resistor values (e.g. 10 ohms), where not only the values above the tolerance (e.g. 10%) are removed, but also those who can be sold as higher precision resistors (eg. 1%). The mean, lower tolerance and higher tolerance should be variables).

Because of the fact that in order to be able to use the Sample function, the PDF should be twice differentiable, the 'truncation' in the middle is realised using logistic functions.

I am able to create said distribution, and produce a DensityPlot, but when I try to take a (even a single) Sample from a RandomVariable from that distribution, Maple keeps calculating and no sample is produced.

GetDist := (mu, alpha, beta) -> Distribution(PDF = unapply(LotRPDF(t, mu, alpha, beta), t)):
T := GetDist(10, .1, 0.1e-1);
DensityPlot(T);
RandomR := RandomVariable(T):
Sample(RandomR, 1);

Where LotRPDF is the function depicted above, mu is the mean (10), alpha is the maximum tolerance (10%), , beta is the minimum tolerance (1%)

Am i overlooking something simple? Or is there a more fundamental error in my approach? I've added the maple sheet with more details.

RandomVariableSample.mw

hi

I am trying to construct a series of 10X10 matrices whose main diagonal contains exactly k ones and other entries zero.

plz suggest thanks

Hi

I am trying to approximate a function in terms of piece-wise constant function:

$$f(x) = \sum_0^N c_iB_i(x)$$

what modules/packages of maple are helpful here? thanks

how to calculate the shorting routing path in cayley graph?

i search that it is related with knuth bendix

In the following code, the evalf prints -32.16... 

restart; S := 8;

sigma := 8/sqrt(2*Pi);

iprec := 151;

evalf(log[2](-(sum(log(round(2^iprec*exp(-j^2/(2*sigma^2)))/2^iprec*exp(-j^2/(2*sigma^2))))*round(2^iprec*exp(-j^2/(2*sigma^2)))/2^iprec, j = 0 .. 7))));

Change the last line to evalf[20](log[2](....)), and re-run *just that line*. It now prints -66.67...

Change the last line to evalf[200](log[2](...)) and re-run *just that line* again. It now prints -151.24... (I have strong evidence to support that the true value is near -151, so I believe this answer.)

Now remove the precision indicator from the command completely and re-run just the last line. It *still* prints -151.24...!

My two questions are: why do I need evalf[200] to get the first three digits of the answer to be correct? and why does setting the evalf precision and then removing it cause the previous precision to persist?

hello everyone. I have an undergradute project i'm currently working on and I'm stuck where I have to use the Differential Transforms Method to solve a problem with boundary conditions at infinity

restart;

Digits := 5;

F[0] := 0; F[1] := 0; F[2] := (1/2)*A; T[0] := 1; T[1] := B; M := 2; S := 1;

for k from 0 to 10 do F[k+3] := (2*(sum((r+1)*F[r+1]*(k+1-r)*F[k+1-r], r = 0 .. k))-T[k]-3*(sum((k+1-r)*(k+2-r)*F[r]*F[k+2-r], r = 0 .. k))-M*(k+1)*F[k+1])*factorial(k)/factorial(k+3);

T[k+2] := (-3*(sum((k+1-r)*F[r]*T[k+1-r], r = 0 .. k))-S*T[k])*factorial(k)/factorial(k+2)

end do; f := 0; t := 0;

for k from 0 to 10 do

f := f+F[k]*x^k;

t := t+T[k]*x^k end do;

print(f);
print(t);

but the problem is that i cant seem to evaluate

or higer diagonal pade-approximant. any help will be greatly appreciated. thank you.

Please help, here is my code:

findproot:=proc(f,var,k)
local i,g,B,n,L,tk;

readlib(rootbound):readlib(realroot):
B:=rootbound(f,var);
g:=expand(subs(var=B*var,f));
if B<1 then g:=numer(g);fi;
n:=degree(g,var);
L:=zero_one(g,var,n,1/B/2^k);
tk:=k+1:
while has(L,0) do
L:=zero_one(g,var,n,1/B/2^tk);
tk:=tk+1:
od:
if L=[] then RETURN([]);fi;
L:=map(proc(x,y) [op(1,x)*y,op(2,x)*y];end,L,B);
end:

I dont know why i cant run this code, it always report: 

Error, (in findproot) improper op or subscript selector

Hello, i am recently doing a lot of my (really simple) equation manipulations with Maple and would like to include an expectation operator E( ) in my symbolic equations. As maple threads E() as a function, differentiating is not very convenient, as i have to replace all D(E) ... manually. I tried defining some properties of E() via the define() function, but when trying to set the behavior of d E(f(x))/dx I am not sure how to use (diff()=result) in the define() function. Any help or ideas are greatly appreciated!

How can I solve this equation 18 *9^(x^2 + 2* x) + 768* 4^((x + 3)* (x - 1)) - 5 *6 ^((x + 1)^2)?

I tried

restart:

A:=18 *9^(x^2 + 2* x) + 768* 4^((x + 3)* (x - 1)) - 5 *6 ^((x + 1)^2);
solve(A=0);

I see that, the equation has three solutions: x = -2, x = -1 and x = 0. I check

f:=x->18 *9^(x^2 + 2* x) + 768* 4^((x + 3)* (x - 1)) - 5 *6 ^((x + 1)^2);

f(-2);

f(-1);

f(0);

Another question, Maple can not solve inequality 

18 *9^(x^2 + 2* x) + 768* 4^((x + 3)* (x - 1)) - 5 *6 ^((x + 1)^2) > = 0.

PS. We can easy to solve the above inequality with Mathematica

Reduce[18 9^(x^2 + 2 x ) + 768 4^((x + 3) (x - 1)) - 5 6 ^((x + 1)^2) >= 0 , x, Reals]

I got x <= -2 || x == -1 || x >= 0

How to generate all basis of a set? (rather an the one basis that basis generates)

Hi all,

Please help in writing finite difference algorithm for a nonlinear PDE using Maple.

for a[j], b[j] known at time n, I want to compute A[j]  for a[j] at time n+1 according to the equation below

EQs:=A[j]-theta*tau*(A[j-1]-2*A[j]+A[j+1])=a[j]+sqrt(a[j])*b[j]*h^2/tau+(1-theta)*tau*(a[j-1]-2*a[j]+a[j+1]) ;

Thanks in advance.

Thanks.

hi guys , i have this warning for solving a complicated equation with 7 parameters. how can i overcome to this warning ?

Download sol.mw

thanks

Dear I want to define a general operator D for Fractional derivative whose behave like this

(D^alpha)(t^beta) = GAMMA(1+beta)*t^(beta-alpha)/GAMMA(1+beta-alpha)

How to generate an undirected graph with a given set of its verticies and a given list/set of the degrees of its verticies?