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Hi,
I am solving large systems of linear equations (mod 2) which are of this form ,
systems:= {0 = f[[1, 4]]-f[[1, 3]], 0 = f[[1, 5]]-f[[1, 3]], 0 = f[[1, 5]]-f[[1, 4]], 0 = f[[1, 6]]-f[[1, 3]], 0 = f[[1, 6]]-f[[1, 4]], 0 = f[[1, 6]]-f[[1, 5]], 0 = f[[1, 7]]-f[[1, 3]], 0 = f[[1, 7]]-f[[1, 4]], 0 = f[[1, 7]]-f[[1, 5]], 0 = f[[1, 7]]-f[[1, 6]], 0 = f[[2, 4]]-f[[1, 3]], 0 = f[[2, 5]]-f[[1, 3]], 0 = f[[2, 5]]-f[[1, 4]], 0 = f[[2, 6]]-f[[1, 3]], 0 = f[[2, 6]]-f[[1, 4]], 0 = f[[2, 6]]-f[[1, 5]], 0 = f[[2, 6]]-f[[2, 4]], 0 = f[[2, 6]]-f[[2, 5]], 0 = f[[2, 7]]-f[[1, 3]], 0 = f[[2, 7]]-f[[1, 4]], 0 = f[[2, 7]]-f[[1, 5]], 0 = f[[2, 7]]-f[[1, 6]], 0 = f[[2, 7]]-f[[2, 4]], 0 = f[[2, 7]]-f[[2, 5]], 0 = f[[3, 1]]-f[[1, 4]], 0 = f[[3, 1]]-f[[1, 5]], 0 = f[[3, 1]]-f[[1, 6]], 0 = f[[3, 1]]-f[[2, 7]], 0 = f[[3, 5]]-f[[1, 4]], 0 = f[[3, 5]]-f[[1, 5]], 0 = f[[3, 5]]-f[[2, 4]], 0 = f[[3, 5]]-f[[2, 5]], 0 = f[[3, 6]]-f[[1, 3]], 0 = f[[3, 6]]-f[[1, 4]], 0 = f[[3, 6]]-f[[1, 5]], 0 = f[[3, 6]]-f[[1, 6]], 0 = f[[3, 6]]-f[[2, 4]], 0 = f[[3, 6]]-f[[2, 5]], 0 = f[[3, 6]]-f[[2, 6]], 0 = f[[3, 7]]-f[[1, 4]], 0 = f[[3, 7]]-f[[1, 5]], 0 = f[[3, 7]]-f[[1, 6]], 0 = f[[3, 7]]-f[[1, 7]], 0 = f[[3, 7]]-f[[2, 4]], 0 = f[[3, 7]]-f[[2, 5]], 0 = f[[3, 7]]-f[[2, 6]], 0 = f[[3, 7]]-f[[2, 7]], 0 = f[[3, 7]]-f[[3, 6]], 0 = f[[4, 1]]-f[[1, 5]], 0 = f[[4, 1]]-f[[1, 7]], 0 = f[[4, 1]]-f[[2, 7]], 0 = f[[4, 1]]-f[[3, 5]], 0 = f[[4, 1]]-f[[3, 7]], 0 = f[[4, 2]]-f[[2, 6]], 0 = f[[4, 2]]-f[[2, 7]], 0 = f[[4, 6]]-f[[1, 5]], 0 = f[[4, 6]]-f[[1, 6]], 0 = f[[4, 6]]-f[[2, 5]], 0 = f[[4, 6]]-f[[2, 6]], 0 = f[[4, 6]]-f[[3, 5]], 0 = f[[4, 6]]-f[[3, 6]], 0 = f[[4, 7]]-f[[1, 5]], 0 = f[[4, 7]]-f[[1, 6]], 0 = f[[4, 7]]-f[[1, 7]], 0 = f[[4, 7]]-f[[2, 5]], 0 = f[[4, 7]]-f[[2, 6]], 0 = f[[4, 7]]-f[[2, 7]], 0 = f[[4, 7]]-f[[3, 5]], 0 = f[[4, 7]]-f[[3, 6]], 0 = f[[4, 7]]-f[[4, 6]], 0 = f[[5, 1]]-f[[2, 6]], 0 = f[[5, 1]]-f[[2, 7]], 0 = f[[5, 1]]-f[[3, 6]], 0 = f[[5, 1]]-f[[4, 6]], 0 = f[[5, 2]]-f[[2, 7]], 0 = f[[5, 2]]-f[[3, 5]], 0 = f[[5, 2]]-f[[3, 6]], 0 = f[[5, 2]]-f[[3, 7]], 0 = f[[5, 2]]-f[[4, 6]], 0 = f[[5, 2]]-f[[4, 7]], 0 = f[[5, 3]]-f[[4, 7]], 0 = f[[5, 7]]-f[[1, 6]], 0 = f[[5, 7]]-f[[1, 7]], 0 = f[[5, 7]]-f[[2, 6]], 0 = f[[5, 7]]-f[[2, 7]], 0 = f[[5, 7]]-f[[3, 6]], 0 = f[[5, 7]]-f[[3, 7]], 0 = f[[5, 7]]-f[[4, 6]], 0 = f[[5, 7]]-f[[4, 7]], 0 = f[[6, 1]]-f[[1, 7]], 0 = f[[6, 1]]-f[[3, 6]], 0 = f[[6, 1]]-f[[4, 7]], 0 = f[[6, 1]]-f[[5, 7]], 0 = f[[6, 2]]-f[[3, 7]], 0 = f[[6, 2]]-f[[4, 7]], 0 = f[[6, 3]]-f[[4, 6]], 0 = f[[6, 3]]-f[[5, 7]], 0 = f[[6, 4]]-f[[5, 7]], 0 = f[[7, 2]]-f[[3, 7]], 0 = f[[7, 2]]-f[[5, 7]], 1 = f[[3, 1]]-f[[1, 7]], 1 = f[[3, 1]]-f[[2, 4]], 1 = f[[3, 1]]-f[[2, 5]], 1 = f[[3, 1]]-f[[2, 6]], 1 = f[[3, 1]]-f[[3, 6]], 1 = f[[4, 1]]-f[[1, 6]], 1 = f[[4, 1]]-f[[2, 5]], 1 = f[[4, 1]]-f[[2, 6]], 1 = f[[4, 1]]-f[[3, 6]], 1 = f[[4, 2]]-f[[3, 5]], 1 = f[[4, 2]]-f[[3, 6]], 1 = f[[4, 2]]-f[[3, 7]], 1 = f[[5, 1]]-f[[1, 6]], 1 = f[[5, 1]]-f[[1, 7]], 1 = f[[5, 1]]-f[[3, 5]], 1 = f[[5, 1]]-f[[3, 7]], 1 = f[[5, 1]]-f[[4, 7]], 1 = f[[5, 2]]-f[[2, 6]], 1 = f[[5, 3]]-f[[4, 6]], 1 = f[[6, 1]]-f[[2, 7]], 1 = f[[6, 1]]-f[[3, 7]], 1 = f[[6, 1]]-f[[4, 6]], 1 = f[[6, 2]]-f[[3, 6]], 1 = f[[6, 2]]-f[[4, 6]], 1 = f[[6, 2]]-f[[5, 7]], 1 = f[[6, 3]]-f[[3, 7]], 1 = f[[6, 3]]-f[[4, 7]], 1 = f[[6, 4]]-f[[4, 7]], 1 = f[[7, 1]]-f[[3, 7]], 1 = f[[7, 1]]-f[[4, 7]], 1 = f[[7, 1]]-f[[5, 7]], 1 = f[[7, 2]]-f[[4, 7]], 1 = f[[7, 3]]-f[[5, 7]], 1 = f[[7, 4]]-f[[5, 7]]};


I have been using msolve as follows; msolve(systems,2);  which returns NULL if there is no solution. This however takes a lot of my computer memory and also take a lot of time since the equations are very many.  I decided to try LinearSolve, but it doesn't give me any solutions even for the ones that I know that the solutions exist. My code was writen as follows:

systems:=as above..

vars := [f[[1, 3]], f[[1, 4]], f[[1, 5]], f[[1, 6]], f[[1, 7]], f[[2, 4]], f[[2, 5]], f[[2, 6]], f[[2, 7]], f[[3, 1]], f[[3, 5]], f[[3, 6]], f[[3, 7]], f[[4, 1]], f[[4, 2]], f[[4, 6]], f[[4, 7]], f[[5, 1]], f[[5, 2]], f[[5, 3]], f[[5, 7]], f[[6, 1]], f[[6, 2]], f[[6, 3]], f[[6, 4]], f[[7, 1]], f[[7, 2]], f[[7, 3]], f[[7, 4]]];

A,b:=GenerateMatrix(systems,var):
LinearSolve(A,b) mod 2;
what I'm I doing wrong? How can I make this fast and in such a way that the solution is computed without taking too much memory?

I also understand that LinearSolve returns the following when there is no solution, "Error, (in LinearAlgebra:-LinearSolve) inconsistent system
", in my case, if there is no solution, I don't want that error to be printed, but I want some variable (call it x) to be printed if a solution is found.

Any help is appreciated.

Vic.

how can i do this GIFs with maple ?

I am trying to solve an equation using surd and I get a strange result.

solve(surd(x^4,8)=-2)
    4, -4, 4 I, -4 I

These solutions are clearly wrong.

The equation (x^4)^(1/8) = -2 has no solution.

This problem is equivalent to asking the computer to solve sqrt(x) = -2

which has no solution in R or C.

 

However if I type

solve((x^4)^(1/8) = -2) , then I get no answer, which is what I expected.

Why does surd behave in this unexpected way.

 

Also another thing I am wondering, why doesn't Maple simplify (x^4)^(1/8) to x^(1/2).

I tried the simplify command it didn't work.

 

I have a number of dots that lie on the sphere. I want to draw a handsome sphere with three axes, put dots on the sphere and connect them. The problem is that some dots are pretty far from the other and so the line connecting them goes under the surface of the sphere and so is not seen. Therefore the question, how the dots can be connected so the line would be seen (or the line would lie on the surface of the sphere)?

Here's the file:ClassicalTrajectoriesAr-CO2.mw

restart;
Digits := 5;
with(ODETools);
with(student);
with(plots);
inf := 5;
with(LinearAlgebra);
equ1 := (1+2*n)*f(eta)*(diff(theta(eta), eta))/(1+3*n)-(diff(theta(eta), `$`(eta, 2))) = 0;
equ2 := ((1+n)*(diff(f(eta), eta))^2/(1+3*n)-(1+2*n)*f(eta)*(diff(f(eta), eta, eta))/(1+3*n))/Bo+(diff(f(eta), `$`(eta, 3)))^n-theta(eta) = 0;
Bcs := f(0) = 0, (D(f))(0) = 0, (D(f))(inf) = 0, theta(0) = 1, theta(inf) = 0;
Bo := 1; n := 2;
SolP1 := dsolve({Bcs, equ1, equ2}, numeric);
Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system
SolP1(0);
SolP1(0)

i want to solve a system , A.b+B.X=0 , which A is 5*5 known matrix, B is 5*2 known matrix , and b is 5*1 and X is 2*1 unknown arbitary matrices ! i want to have solution for b and X . whatever they can be ! just equation to be solved !

restart:

A:=Matrix(5,[[-0.9800,0,0,-0.0160,0],[1.0000,0,0,0,0],[-2.1900,-9.7800,-0.0280,0.0740,0],[77.3600,-0.7700,-0.2200,-0.6700,0],[0,-79.9700,-0.0300,0.9900,0]]);

A := Matrix(5, 5, {(1, 1) = -.9800, (1, 2) = 0, (1, 3) = 0, (1, 4) = -0.160e-1, (1, 5) = 0, (2, 1) = 1.0000, (2, 2) = 0, (2, 3) = 0, (2, 4) = 0, (2, 5) = 0, (3, 1) = -2.1900, (3, 2) = -9.7800, (3, 3) = -0.280e-1, (3, 4) = 0.740e-1, (3, 5) = 0, (4, 1) = 77.3600, (4, 2) = -.7700, (4, 3) = -.2200, (4, 4) = -.6700, (4, 5) = 0, (5, 1) = 0, (5, 2) = -79.9700, (5, 3) = -0.300e-1, (5, 4) = .9900, (5, 5) = 0})

(1)

B:=Matrix((5,2),[[-2.44,0.58],[0,0],[0.18,19.62],[-6.48,0],[0,0]]);

B := Matrix(5, 2, {(1, 1) = -2.44, (1, 2) = .58, (2, 1) = 0, (2, 2) = 0, (3, 1) = .18, (3, 2) = 19.62, (4, 1) = -6.48, (4, 2) = 0, (5, 1) = 0, (5, 2) = 0})

(2)

b:=Matrix((5,1),[y[1],y[2],y[3],y[4],y[5]]);

b := Matrix(5, 1, {(1, 1) = y[1], (2, 1) = y[2], (3, 1) = y[3], (4, 1) = y[4], (5, 1) = y[5]})

(3)

X:=Matrix((2,1),[[x[1]],[x[2]]])

X := Matrix(2, 1, {(1, 1) = x[1], (2, 1) = x[2]})

(4)

M:=A.b+B.X

M := Matrix(5, 1, {(1, 1) = -.9800*y[1]-0.160e-1*y[4]-2.44*x[1]+.58*x[2], (2, 1) = 1.0000*y[1], (3, 1) = -2.1900*y[1]-9.7800*y[2]-0.280e-1*y[3]+0.740e-1*y[4]+.18*x[1]+19.62*x[2], (4, 1) = 77.3600*y[1]-.7700*y[2]-.2200*y[3]-.6700*y[4]-6.48*x[1], (5, 1) = -79.9700*y[2]-0.300e-1*y[3]+.9900*y[4]})

(5)

eval(M,y[1]=0)

Matrix([[-0.160e-1*y[4]-2.44*x[1]+.58*x[2]], [0.], [-9.7800*y[2]-0.280e-1*y[3]+0.740e-1*y[4]+.18*x[1]+19.62*x[2]], [-.7700*y[2]-.2200*y[3]-.6700*y[4]-6.48*x[1]], [-79.9700*y[2]-0.300e-1*y[3]+.9900*y[4]]])

(6)

 

 

 

Download solve.mw


actually the problem to be solved is M=0 ! which directly goes to y[1]=0;
after that , how can i find other unknowns so that M=0 is ok. tnx

I have a worksheet (.mw) file that I want to export using a statement to avoid tedious GUI clicking.

How to export a worksheet (.mw) to Maple Input (.mpl) using a statement in the worksheet, so I can just execute the worksheet, and then the Maple Input (.mpl) file is generated?

 

How to get directory name of current worksheet file ?

 

So for example if my current worksheet .mw file is saved at "c:\temp\temp\work.mw" I can get the directory part as "c:\temp\temp\".

 

I am getting the error that maple was unable to allocate enough memmory for the computation. I have seen that some of the values could have been stored in a remember table so that they are accessed whenever needed. I am however using arrays and maple cannot tell when the entries in an array change, how about option cache? can that be useful? if not, how can I optimize my storage space?

Is it possible to stop simplifying the expressions automatically in Maple in the following case:

> 2*x-5>3*x-6;

Thank you.

in internet or maple, is there a neural network package in maple?

i find example link after googled, however, still feeling not easy to apply to data.

is there the most simplest version for two columns of data ?

which algorithm can be used to mining data set in maple after feature extraction

hope systematic and automatic doing this instead of using eyes

 

i feel derived attributes are unlimited, how to know sufficient?

Hi,

 

Can Maple solve mathematical models? And can I use it to solve LP and NLPs?

in real practice, 

what is application of the cycles in algcurves[homology] ?

is there any book teaching about the use of this function in maple?

I want to define a function f in Maple such that $f(x[1,2]^{-1/3})=\{1,2\}, f(x[1,2])=\{1,2\}, f(x[1])=\{1\}, f(x[1]^{1/3}) =\{1\}$, f(x)=empty set. How could I do this in Maple? Thank you very much.

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