I'm trying to numerically integrate components of the procedure-vector.

interim:=t->evalf(int(r1_lab_deriv(x)[1],x=0..t));

interim(5);

Getting this type of error:

Error, (in r1_rot_deriv) invalid input: fdiff expects its 2nd argument, N, to be of type {integer, name, list(integer), list(name), list(name = constant), set(name), set(name = constant), name = constant}, but received t = x

 A bit of googling gave me an impression that integration of procedures can be rather quirky.

File: ProcIntergration.mw (Problem occurs in the last lines of the file.)

I am learning how to use Maple with boundary value ODE. Given this ODE

y''''(x)+ lam* y(x) =0

with some B.C., say  y(0)=0,y'(0)=0,y''(L)=0,y'''(L)=0, where L is length.

I can't figure the correct syntax to use. It seems Maple do not like the syntax I am using, but it works on a second order ODE?

Here is my attempt:

restart;
assume(lam>0); assume(L>0);
bc:=y(0)=0,D[1](y)(0)=0,D[2](y)(L)=0,D[3](y)(L)=0;
dsolve({diff(y(x),x$4)+lam*y(x)=0,bc},y(x));

Error is 

Error, (in evalapply) too few variables for the derivative with respect to the 2nd variable
Error, (in dsolve) found the following equations not depending on the unknowns of the input system: {bc}

But on a simpler second order ODE, the syntax works

restart;
assume(lam>0); assume(L>0);
bc:=y(0)=0,D[1](y)(0)=0;
dsolve([diff(y(x),x$2)+lam*y(x)=0,bc],y(x));

No error. 

Is the syntax I am using in first example wrong? what would be the correct syntax? I googled for long time, and can't find one example that shows how to use BVP with higher order ODE. I am Maple newbie.

hi i have this code that doesnt work and I cant find the problem. I cant make the matrix include more than 2 rows. i want this to give me the whole nxn matrix, and then the solution to the wronskian. 

can you pls help?:) thanks! 

with*linalg;
funcs := [x, 3*x, x^2, 5*x];
n := nops(funcs);
print*n;
printlevel := n;
count := 1;
listM[count] := funcs;
for i from 2 to n do listN := diff(funcs, `$`(x, i-1));
count := count+1;
listM[count] := listN end do;
M := convert(listM, matrix);
det(M)

how to fasten dsolve and is it possible to timeout faster if it know no solution earlier?

i split into near 500 blocks of nested for loop, total around 42 billions trials

i run in cmaple, 

i see it run the first 4 blocks of code and output to files,  which are daff001, daff002, daff003 and daff004

it seems that it can run parallel intelligently though i write in serial lines.

but it run a very long time, still running near first 4000 records

window 10 use 3.4GB memory, only 4GB memory rest

but 4000 records use more than 4GB memory

i just hope to run 1000 records every day, hope 1000 records can be finished within a few hours

and plan to run around 500days

restart:
read "D:\\daff2039mm.m":
with(combinat):
appendto("D:\\daff001.txt");
for ii from 1 to 1 do
for jj from 1 to 1 do
for kk from 1 to 1 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii] , mm[jj] , mm[kk] ],[a(t), b(t), c(t)]);
if nops([sol]) = 1 then
print([mm[ii], mm[jj], mm[kk]]);
print(sol);
print(" * **");
end if:
end if:
end if:
od:
gc();
od:
od:

restart:
read "D:\\daff2039mm.m":
with(combinat):
appendto("D:\\daff002.txt");
for ii from 1 to 1 do
for jj from 1 to 1 do
for kk from 1 to 1001 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii] , mm[jj] , mm[kk] ],[a(t), b(t), c(t)]);
if nops([sol]) = 1 then
print([mm[ii], mm[jj], mm[kk]]);
print(sol);
print(" * **");
end if:
end if:
end if:
od:
gc();
od:
od:

restart:
read "D:\\daff2039mm.m":
with(combinat):
appendto("D:\\daff003.txt");
for ii from 1 to 1 do
for jj from 1 to 1 do
for kk from 1001 to 2001 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii] , mm[jj] , mm[kk] ],[a(t), b(t), c(t)]);
if nops([sol]) = 1 then
print([mm[ii], mm[jj], mm[kk]]);
print(sol);
print(" * **");
end if:
end if:
end if:
od:
gc();
od:
od:

restart:
read "D:\\daff2039mm.m":
with(combinat):
appendto("D:\\daff004.txt");
for ii from 1 to 1 do
for jj from 1 to 26 do
for kk from 2001 to 2001 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii] , mm[jj] , mm[kk] ],[a(t), b(t), c(t)]);
if nops([sol]) = 1 then
print([mm[ii], mm[jj], mm[kk]]);
print(sol);
print(" * **");
end if:
end if:
end if:
od:
gc();
od:
od:

restart:
read "D:\\daff2039mm.m":
with(combinat):
appendto("D:\\daff005.txt");
for ii from 1 to 1 do
for jj from 26 to 51 do
for kk from 2001 to 2001 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii] , mm[jj] , mm[kk] ],[a(t), b(t), c(t)]);
if nops([sol]) = 1 then
print([mm[ii], mm[jj], mm[kk]]);
print(sol);
print(" * **");
end if:
end if:
end if:
od:
gc();
od:
od:

i have already release memory with gc() in the most inner for loop ]

,but it still use up my memory

once it printed two lines each time, actually it can release memory

but why it still use up memory

read "D:\\hello.m":
with(combinat):
appendto("D:\\gogogo.txt");
for ii from 1 to 2040 do
for jj from 1 to 2040 do
for kk from 1 to 2040 do
if ii < jj and jj < kk then
if mm[ii] <> mm[jj] and mm[jj] <> mm[kk] then
sol := dsolve([mm[ii],mm[jj],mm[kk]],[a(t),b(t),c(t)]);
print([mm[ii],mm[jj],mm[kk]]);
print(sol);
print("***");
end if:
end if:
od:
gc();
od:
od:

i can only think

use c# to generate code with file write, nested for loop every 1000 records 

is it the only way to do?

int counter = 0;
for (int i=1; i<=2040; ++i)
{
for (int j = 1;j <= 2040; ++j)
{
for (int k = 1; k <= 2040; ++k)
{
if(counter % 1000 == 0)
{
Console.Write(i.ToString() + ","+j.ToString() + ","+k.ToString());
Console.Write("\r\n");
}
counter = counter + 1;
}
}
}

for ii from 1 to 2039 do
for jj from 1 to 2039 do
for kk from 1 to 2039 do
print(hello(ii,jj,kk));
od:
od:
od:

Hello, 

I am not sure how to find the Heaviside Laplace transform 

H(t-1)e^(3t-3)

Thank you:)

hello. I need help in finding the wronskian for any list of functions. i.e. if I input a nxn matrix i want it to calculate the determinant.  like here

with(linalg):
listM:=[sol,diff(sol,x)];
M:= convert(listM,matrix);
det(M);

Hello people in mapleprimes,

I put a function h into my original package named z5.

And, I used it as

> h(x+y);

then, the output is

x*`z5:-h`(x)/(x+y)+y*`z5:-h`(y)/(x+y)

I want to have

x*h(x)/(x+y)+y*h(y)/(x+y),

not z5:-h for h.

How should I do for "h" to be kept from changing  to "z5:-h"?

Best wishes.

taro

part other than z5 needs designating a directory for library.**********

>new_lib_dir3 :=Please put an appropriate directory

>z5:=module() option package;
>export numer_expand,h;
>numer_expand := a->expand(numer(a))/denom(a); h:= F-> expand
>(evalindets(D(F)/F, specfunc(D), d-> op(d)*'h'(op(d)))); end module;

>LibraryTools:-Save('z5',new_lib_dir3);
>restart;

>libname:=new_lib_dir3,libname;

>with(z5);

>h(x+y);

               x*`z5:-h`(x)/(x+y)+y*`z5:-h`(y)/(x+y)

Hi!

Suppose, we need to compute this integral:

int(sqrt(exp(2*I*t)-1),t) from t=0 to t=Pi

If we write this as definite integral, we get right answer: 2*sqrt(2)-(1/2)*ln(17+12*sqrt(2))

But in case of indefinite integral (computing antiderivative) one gets I*arctan(sqrt(exp(2*I*t)-1))-I*sqrt(exp(2*I*t)-1). Substitution t=Pi and t=0 both lead to 0, so we can't transform antiderivative to definite integral. What is the reason?

I have a problem with the right-click command „Unit Formatting“. Here is an example: I am trying to get in result in kW instead of W. This works as long as the value is assigned to the variable using := . If the value is calculated I cannot change the unit.

Right-clicking P and P2 and selecting „Unit Formatting“ I get the following selection menu

Right-clicking P3 offers no units to be selected. Entering a Custom Unit returns an error message.

Is that behaviour normal for Maple or am I making a mistake?

I want to draw multiple curves based on a single equation in which a parameter will change giving different curves. I want these curves to be in the same frame. Is there a single line code for the same? 

Hi,

I have a PDE which I would like to group certain terms in common. They are all general functions and do not all share variables in common.

It is easier to explain in the script attached.

Any guidance anyone can offer would be greatly appreciated. 

Thank you 

question3.mw

Hi guys,

I am trying to solve a Fredholm equation of the second kind using Maple. An analytical expression cannot be in principle found. I was wondering whether Maple does numerical evaluation of such integral equations. Please see the equation in attach. Any help is highly appreciated.

Thanks

F

Question.mw