# Items tagged with randomrandom Tagged Items Feed

### Simple code for MonteCarlo approximation of Pi...

October 11 2014
1 5

Hello everybody,

But for starting easy, I try this:

with(RandomTools[MersenneTwister]);
directpi := proc (n)
local i, x, y, N;
N := 0;
Digits := 2;
for i to n do
x := GenerateFloat();
y := GenerateFloat();
if x^2+y^2 < 1 then
N := N+1:
end if:
end do:
N;
end proc;

evalf(directpi(4000)/(1000.0), 4);

3.176

I would like to know if this code is appropriate and if it is possible to have a random number between -1 to 1 so it will be easier to plot the points in the square with the circle inside.

Thank you.

--------------------------------------
Mario Lemelin
Maple 18 Ubuntu 13.10 - 64 bitsMaple 18 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

### How to compile statistics each number in a sequenc...

August 23 2014
1 16

RandomCompositions:= proc(n::posint, k::posint)
local
C,
Compositions:= [seq(C-~1, C= combinat:-composition(n+k, k))],
Rand:= rand(1..nops(Compositions))
;
()-> Compositions[Rand()]
end proc:

R:= RandomCompositions(9,6):
n:= 2^13:
S:= 'R()' $n: I want to compile statistics each number in a sequence cannot occur over twice. The sequences that do not fit the rule above must be ommitted. The statistic is Fermi-Dirac statistics. confused the Bose-Einstein condensation and Fermi-Dirac statistics. But the theory is right. ### How to count the same random sequence as one... August 21 2014 0 6 RandomCompositions:= proc(n::posint, k::posint) local C, Compositions:= [seq(C-~1, C= combinat:-composition(n+k, k))], Rand:= rand(1..nops(Compositions)) ; ()-> Compositions[Rand()] end proc: R:= RandomCompositions(9,6): n:= 10: S:= 'R()'$ n;

S := [4, 1, 1, 1, 2, 0], [3, 2, 1, 1, 0, 2], [0, 1, 1, 0, 0, 7], [0, 1, 1, 5, 0, 2], [1, 0, 3, 1, 3, 1],

[1, 3, 1, 1, 0, 3], [1, 4, 2, 0, 2, 0], [5, 0, 0, 3, 1, 0], [1, 1, 1, 4, 0, 2], [0, 1, 2, 1, 0, 5]

[4, 1, 1, 1, 2, 0] , [1, 1, 1, 4, 0, 2]  and [0, 1, 1, 5, 0, 2] , [0, 1, 2, 1, 0, 5]  are same number

but different order.

There are two same sequence. I want to  count  as one, and compile statistics the summation, and

divide by 8.

the result

0=14/8

1=17/8

2=6/8

...

4=2/8

5=2/8

...

### how to count the number summation ...

August 15 2014
1 10

RandomCompositions:= module()
local
Compositions, Rand,

RandomCompositions:= module()
local
Compositions, Rand,
ModuleApply:= proc(n::posint, k::posint)
local C;
Compositions:= [seq(C-~1, C= combinat:-composition(n+k, k))];
Rand:= rand(1..nops(Compositions));
()-> Compositions[Rand()]
end proc;

end module:
R:= RandomCompositions(8,6):
seq(R(),i=1..10);

[0, 0, 2, 6, 0, 0], [1, 0, 0, 3, 4, 0], [0, 3, 3, 2, 0, 0],[1, 2, 4, 0, 1, 0], [0, 4, 0, 1, 3, 0],

[2, 0, 1, 4, 1, 0],[2, 0, 1, 1, 3, 1], [1, 0, 4, 2, 1, 0], [1, 3, 0, 2, 0, 2],[2, 0, 3, 2, 1, 0]

with(Statistics):
Tally(R());
[0 = 1, 1 = 4, 4 = 1]

I want to count the 0 to 8 respectively summation,and divide by i.

But the  seq command  R() isn't conform  with Tally command R() .

Thanks.

### how to set random summation...

August 06 2014
1 5

a:=rand(0..8):
b:=rand(0..8):
c:=rand(0..8):
d:=rand(0..8):
e:=rand(0..8):
f:=rand(0..8):
a()+b()+c()+d()+e()+f()=8;

This is my  programming code.

I want ot set six random summation is  8.

But the random summation can't reach 8.

### Fast random generation...

July 15 2014
2 2

It says at

http://www.maplesoft.com/products/maple/new_features/maple18/Language_Programming.aspx#random

"When generating matrices and vectors of floats and integers, these flavors are very fast. "

But when I compare the new

time[real](Generate(('Matrix')(float, 300, 300)))

and

time[real](RandomMatrix(300, 300))

I find RandomMatrix over 300 times faster. Am I doing something wrong, or is RandomMatrix still the fastest way to generate random numbers?

### how to generate random numbers with normal distrib...

June 12 2014
2 4

I want to generate random numbers following the normal distribution within a fixed interval.

For example, I want generate 10 random numbers in the interval [2903.5-5, 2903.5+5]. These random numbers should follow the normal distribution with mean 2903.5 and  standard deviation \sigma=3.

How can I do this?

Thanks.

### How to save values stored in the variables in a wo...

June 01 2014
0 2

My problem is i am working with a very large randomly generated output, generated using maple's builtin in random generating functions. I have the output which i want to investigate but i want to be able to reproduce this result when i save and close the worksheet. Since the list of generators is very long copy pasting is not very nice and i donot know the seed of these generaters. I want to ask if i can store the values in variable in the worksheet so that when i open the worksheet i can get the same random generates stored in the variable.

### Is there a function to generate random numbers wit...

May 13 2014
0 15

Hello guys,

I think that the title explains the question very well. Is there any function in MAPLE that allows me to generate N random numbers considering a mean value, standard deviation and a percentile?

Thank you,

### How do I generate a random matrix of this form?...

May 11 2014
2 3

I want to generate a random matrix of size m x n as follows: for each i between 1 and m, take a random p_i number according to some fixed distribution (for example, uniform distribution in [0,10]). These numbers p_i are independent. Then I'll form a random matrix whose (i,j)-entry is chosen according to a probability distribution that depends on the parameter p_i (for example, it could be Poisson(p_i)). So entries in the same row are independent.

How can I do that?

February 19 2014
1 4

Hi,

I tried to use generated random as following

***

for j from 1 to 5 do
c:=rand(0..1):
d:=c();
print(random number,c(),d);

if c()=1 then

print(Y)
else
print(N);
end if;
end do:

***

The output is

****

random number, 1, 0

Y

random number, 1, 1

Y

random number, 1, 1

N

random number, 1, 1

N

random number, 0, 0

N

****

Why the output numbers in one line are different? And Using "if" sentence seems do not correspond to the printed "c()" value..

Thank you very much in advance!

### obtaining c.d.f from probability mass function...

December 28 2013
2 1

How to calculate c.d.f from probability mass function. Suppose that the pmf of a discrete random variable is given : f(x)=(2*x+1)/25, x=0,1,2,3,4

### How do I randomize 19 particular items in maple?...

November 19 2013
1 1

I have a set of 19 different items I need randomize, lets call them A-S. I tried the Random command, Random(19,A-S) listing all of the possiblities. I want each letter to be used once in that 19 times and using this way does not do that. Is there another command I can use to achieve this?

### randomize a subset...

November 05 2013
0 10

Suppose I broadcast a game show where every episode there is 5 randomly chosen topics from 8 possible topics (A,B,C….). how can I get maple to do this automatically?

I thought I could use

> with(combinat):

> choose([A,B,C,D,E,F,G,H], 5);

of course the output comes out ordered. is there some way to randomize it? or another way? rgds

### How do I get randomize(#) to work in Maple 17...

September 02 2013
0 3

If I put in the randomize(#) command with the same actual number each time before generating a sequence of random numbers,  I would expect to get the same sequence of results from repeated use of

round( Generate(distribution(DiscreteUniform(5,10))) )

each time. Actually, I get completely different sequences of numbers.

This also happens with the alternative method of SetState in RandomTools

This is not only annoying...

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