Let L = {a1, a2, ..., an} (or L = [a1, a2, ..., an]) with is homogeneous polynomial. How to create function createDegree() return elements of degree <= n from L.

Expamle. L = {a-2b, b^2, (a+c)^2}.

createDegree(L,1) return {a - 2b}.

createDegree(L,2) return {b^2, (a - 2b)^2, (a+c)^2, a - 2b}.

createDegree(L,3) return {b^2, (a - 2b)^2, (a - 2b)^3, (a+c)^2, (a - 2b)b^2, (a - 2b)(a+c)^2, a - 2b}.

Thanks you very much.

Hello everyone!

Could somebody help me with reading data from Huge txt-file? My file contains matrix with 10 columns and 10^6 rows. Datatype is float[8].

I use "ImportMatrix" comand to obtain data from file, but it is rather slow ~ 33 sec.

is there an efficient way to read file directly using Maple? Or I should use C-dll to read file faster?

I want to calculate the ratio of the length of day and night for every latitude on earth ?
but i confused on using Maple in a wise way for finding the formula !
this is my demonstration :

shekofte000.mw
 

Download shekofte000.mw

As you see above, when I want to evaluate the definite integral, Maple can not provide the desired result. Why does this happen? How can I do so that Maple can calculate this integral?

Hello

Tryed to work this application, but problems encountered.

http://www.maplesoft.com/applications/view.aspx?SID=89020

and

http://www.mapleprimes.com/maplesoftblog/89021-The-Traveling-Salesmans-US-Roadtrip

I installed PostgreSQL, (i believe version 8.4 from 2010) which I found at "oldapps" (the current version is 9.6).

I'm running Win 7, 64 bit. Anyways, I have to change the paths below "Query the database":

driver := LoadDriver(classpath = "C://Program Files (x86)//PostgreSQL//pgJDBC//postgresql-8.4-701.jdbc4.jar");

conn := driver:-OpenConnection("jdbc:postgresql://localhost:5432/zip_codes", "postgres", "password");

I fail to see pgJDBC folder and a search for .jar files in the directory yields only 3 jar files, non resembling the above. tried example.jar

same error. heres a screenshot of my directory

Please i need help to plot the graph of f'' against episoln using the below BVP

HELP.mw

I want to plot the following equation

((1/2)*x*tan(log((1/5)*(2*(x^2+y^2)))) = y

I tried:

with(plots, implicitplot)

implicitplot((1/2)*x*tan(log((1/5)*(2*(x^2+y^2)))) = y, x = -5 .. 5, y =-5..5, numpoints = 1000, gridrefine = 6, color = red)

but result is strange... 

How to change the numer of hatchings in a 3d plot?

Hello, I have a function defined as

                                                   g :=  (x, y)->diff(u1(x, y), x, x)+diff(u2(x, y), x, y). 

I want to define another function as follows

                                                           f :=  (y) ->subs(x = 0, g(x, y)) ,

Now, when I want to calculate numerical values for the new function f(0), f(0.1), f(0.2),..... and so on. The following massage appear

Error, (in f) invalid input: diff received 0, which is not valid for its 2nd argument.

What is the problem here.

Amr
 

I'm curious to know if anyone has written a procedure to optimize the VRP with time windows / constraints.

I have a system of ode's

restart:with(plots):
eq1:=((diff(f(x),x$3)))+f(x)*diff(f(x),x$2)-a*diff(f(x),x$1)^2=0;
eq2:=(diff(g(x),x$2))+b*f(x)*diff(g(x),x$1)=0;
bc1:=f(0)=0,D(f)(0)=1,D(f)(5)=0,g(0)=0.5,g(5)=0;

dsolve can solve it easily.

sol:=dsolve(subs(a=0.5,b=0.5,{bc1,eq1,eq2}), numeric):

Now I was to use the numerical data from the sol in the following expression

Expr:=a*f(x)+b*g'(x)+c*f'(x)*g(x) # at x=1:

to make a table of this form a  b  c  Expr, where a, b, c vary simultaneously between 0 and 1 by 0.2 producing data for Expr.

Any suggestions? 

Hi everyone!

I have a question: what is the simpliest way to generate colorbar for spectrogram?

Now I use "valuesplit" to assign dependece "z"-value from color.

My programm. My test file: "Signal.txt".

filtered_spectrogram.mw

Signal.txt

P.S. I use Maple 2016.

Helle everybohy,

I need to setup a metric tensor in 3-d but with the varalble r, and .  So I try this:

>with(Physics); Setup(mathematicalnotation = true, dimension = 3)

>Setup(coordinates = spherical[r, theta, varphi], metric = M)

where M is the metric that I need to use.  But the last command does not work.  Il I don't write [r, theta, varphi], it work but it's r, theta and t.

Any hint on this please?

Thank you in advance for your help.

Mario Lemelin

mario.lemelin@cgocable.ca

all
I need your help  to give an answer to  this question
I would like to construct a matrix with condtion that comes in picture
How can i do this with maple????
my matrix is n+1*n+1

Hi all,

How to calculate this integral:

for k>0,m>0

Int(exp(-(1/2)*v/k)*v^3*exp((1/2)*v/m)*Ei(1, -(1000*I)*v+(1/2)*v/m), v = 0 .. infinity)

I'm  tried to take advantage of with(IntegrationTools) but I failed

and and I got a strange result ,like this:

Integral.mw