There is million items in list, 

what is the difference between seq and for loop ?

is seq faster than for loop?

it is very slow when running code below, how to speed up this part of code?

https://gist.github.com/LovelyYanki/c0b61fbb9d5954b34e03#file-gistfile1-txt

HSKeyIn := Table();
for ij from 1 to 1685159 do
s := solve([mm[ij][1,1]=1,mm[ij][1,2]=1,mm[ij][1,3]=1],[a,b,c]):
if nops(s) > 0 then
if (rhs(s[1][1]) = 1 or rhs(s[1][1]) = 0) and (rhs(s[1][2]) = 1 or rhs(s[1][2]) = 0) and (rhs(s[1][3]) = 1 or rhs(s[1][3]) = 0) then
#print(lhs(indices(T3, pairs)[ij])):
#print("***"):
h := HilbertSeries([mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]], {a,b,c}, z):
#print(h):
if not assigned(HSkeyIn[h]) then
if mod(ij, 100) = 0 then
print(ij):
end if:
HSkeyIn[h] := [[mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]]]:
else
if mod(ij, 100) = 0 then
print(ij):
end if:
HSkeyIn[h] := [op(HSkeyIn[h]), [mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]]]:
end if:

end if:
end if:
od:

mm := [[a, 1], [a, b]];
mmseq := {seq(mm[ij],ij=1..2)};

how to filter above in seq when any items in the [] has 1

criteria is below

if mm[ij][1] = 1 or mm[ij][2] = 1 or mm[ij][3] = 1 then
Dummy := 0:
else
mm2 := [op(mm2), mm[ij]]:
end if

Hello,

In a course I am looking at, the system of units is mostly in FPS.  Wich I never use.  But they ask sometime to convert it to SI.  But with Maple, I have a problem:

For Force, it use lb that I cannot convert into N

So what unit should I use to convert FPS to SI for the force.

I know that slug*ft*s^(-2) convert to N with no problem.

Thank you for your help.

--------------------------------------
Mario Lemelin

Maple 2015 Ubuntu 14.04 - 64 bits
Maple 2015 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

Cheers!

I'm having a problem with my student work, about to have a solution of 6 equations... Can help me in this file? i dont know how to solve this... this had-me a null solve...

Thanks for the help =)

Download Equacoes_universais_T12_-_4.mwEquacoes_universais_T12_-_4.mw

Dear Maple users

I am delighted that Maple has builtin commands to plot so many polyhedrons in 3D. Here I am talking about the polyhedraplot command in the plots package. I was however disappointed that the socalled Truncated Icosahedron is not supported (not present in the supported list ...). My first question is:

1. Why isn't it supported?

It seems more relevant than many of the other polyhedrons which are supported. It is a member of the Archimedian Solids (see https://en.wikipedia.org/wiki/Truncated_icosahedron). Besides it is the basic structure for soccer footballs. I found out that a TruncatedIcosahedron command is available in the geom3d package. This command is able to deliver data for the faces and more. With this command I succeded in writing a small program to actually plot this polyhedron in 3D:

-----------------------------------------------------

restart;
with(geom3d):
with(plots):
TruncatedIcosahedron(football,point(C,(0,0,0)),1):

PlotFootball:=proc(tr::float)
    
    local i::integer,
         FootballFace::Vector(datatype=float[8]),
         plotFace::Vector(datatype=float[8]);    
    
    for i from 1 to 32 do
        FootballFace[i]:=faces(football)[i];
        plotFace[i]:=polygonplot3d(Matrix(FootballFace[i]),axes=none,scaling=constrained,transparency=tr);
    end do;
    
    display(seq(plotFace[i],i=1..32)):
    
end proc:

PlotFootball(0.00);

-----------------------------------------------------

Since I am not really experienced in programming in Maple, here is my last question:

2. Can I simplify something in my code above?

Best wishes,

Erik

People im with error to show a plot, this is a wor for universty about mechanic materials, and i'm with this error... do not show the plot... before, i've a error because the variable x has values, and i've to unassign to have this.. without unassign, has error in domin of the plot... i dont know how to do this ! And ive to send the work today. 

Someone can help me about this?


Value of variables:

plot algoritm...

Thanks !

in page 137 of an introduction to groebner bases

how to eliminate the redundant solution (y^2-x*z, 0, -x^2+y*w)

from 3 of them?
eliminate({y,y^2-x*z,-z}, {x, y, z, w});
eliminate({-x,0,y}, {x, y, z});
eliminate({w,-x^2+y*w,-x}, {x, y, z, w});

ma := allstructs(Permutation([1, 1, 1, 2, 2, 2, 3, 3, 3]), size = 3);

above is fast

but below is very slow.
ma2 := allstructs(Permutation(ma), size = 3);

just for all combinations of matrix , replicateM in haskell is the fastest.

in maple, ma2 := allstructs(Permutation(ma), size = 3); is very slow

What is the best source of learning maple for an abecedarian to become a professional?

Hi

I can't understand difference between plots!

Please expailn it.

Thanks.

plot({sqrt(x+2*sqrt(x-1))+sqrt(x-2*sqrt(x-1)), sqrt(x-2*sqrt(x-1)), sqrt(x+2*sqrt(x-1))}, x = -3 .. 3)

strange_behavior.mw

Edit. Replaced worksheet.

Hi,

I have a problem with the adaptive question designer: when I use the multiple choice question type then occasionally parts of the question environment appear multiple times in the text, duplicating each time I reopen the question to edit. This happens in particular if the answers are a bit longer (4-5 lines each). So far I couldn't figure out how to fix this, does anyone have a similar problem? 

Many thanks for your help!

Please help me to solve this integration

restart; with(LinearAlgebra); int(exp(-(ln(z/(snr*B^2))+4*sigma^2)^2/(32*sigma^2))*eta^2*(y/z)^((1/2)*eta^2-1)/(z*sqrt(32*Pi*sigma^2)*(2*sqrt(y*z))*(2*A[o]^(eta^2))), z, z = y/A[o]^2 .. infinity);

restart; with(LinearAlgebra); int(exp(-(ln(z/(snr*B^2))+4*sigma^2)^2/(32*sigma^2))*eta^2*(y/z)^((1/2)*eta^2-1)/(z*sqrt(32*Pi*sigma^2)*(2*sqrt(y*z))*(2*A[o]^(eta^2))), z, z = y/A[o]^2 .. infinity)

Maple 2015:

simplify(1-2*sin(x)^2);  gives 2*cos(x)^2-1

I looked at help trying to understand why Maple thinks 2*cos(x)^2-1 is simpler than 1-2*sin(x)^2 but did not see it. I was expecting to see cos(2*x) as a result.

Is there a place to understand more Maple's simplification rules other than the help page? http://www.maplesoft.com/support/help/maple/view.aspx?path=simplify%2fdetails

I need to show that the following expression,
a^3b-a^3c+a^3z+a^3x+a^3y-a^2bx+a^2by+a^2cx-a^2cy-a^2zx+a^2zy-a^2x^2+a^2y^2-abcz-abcx-aczx-acx^2+b^2c^2+2bc^2x+c^2x^2-b^2c-2bcx-cx^2,

is positive

given that:

1. a,b,c,x,y,z are positive real numbers

2. a>b+x

3. c<b+y

I know a priori that the expression is indeed positive, but I do not know how to show it, or how to use Maple to do it?

Specifically, how can I use Maple to **partially factorize** the expression in terms of the expressions a-b-x and c-b-y?

Thanks for any help.