I recently upgraded from Maple 2019.2 directly to Maple 2022.2. I now have a problem with any double or triple literal subscripted variable in old worksheets or in new ones under Maple 2022.2. Double and triple indexed subscripts work just fine under Maple 2019.2.

If in Maple 2022.2 I enter X__a I get a proper X_a.  If I enter Y__a,b I get 'Y_a,b' Note the leading prime preceeding the Y and the trailing prime following the subscript b down at the subscript level. This behavior holds for triple literal subscripts.

On the other hand, indexed subscripts work just fine in Maple 2022.2. If I enter X[a] I get X_a. If I enter Y[a, b] I get Y_a,b .

How do I fix this behavior? When did it start? My jump from Maple 2019.2 to Maple 2022.2 was due to changing companies during the Covid period. I am using Maple on a Mac.

I have not tested literal superscripts or combinations of literal subscripts and superscripts.

Any help will be greatly appreciated. I use literal double and triple suscripts all the time to distinguish between vector and matrix components in different coordinate systems.

Neill Smith

My old company went belly up during the COVID period. My old email address is now dead as a doornail.

I can login to MaplePrimes using the old email address, post questions, etc.

However, I can't change my account email address becaue Maplesoft sends a verification message to the OLD email address.

If I post a question, I can read the replies here. However, any replies sent to my OLD email address just disappear.

How do I change my account email address under this situation?

Thanks.

Hello everyone,

I am trying to solve a system of 4 ODEs that describe a physical system, however, I get the message:

Error, (in dsolve/numeric/bvp) matrix is singular

Any help is much appreciated. The initial conditions are such that to find solution in steady state, that means, v(0)=v(period) and so on with all variables.

Download LLCcircuit_SteadyState_numerical.mw

Hello everyone,

I want to solve a simple ODE numerically having a piecewise periodic function in the ODE.

The periodic piecewise function definition is taken from this  post.

When solving using "dsolve" numerical, I get this error:

Error, (in f) unable to store '100000*square_wave_periodic' when datatype=float[8]

restart;
d := .5;
fs := 100*10^3;
Vin := 10;
C := 10*10^(-6);
R := 10;
L := 10*10^(-6);

DEFINE PERIODIC FUNCTION
square_wave := proc (t) options operator, arrow; piecewise(0 <= t and t <= d/fs, Vin, d/fs < t and t < 1/fs, 0) end proc

square_wave_periodic := proc (t) options operator, arrow; square_wave(t-floor(t*fs)/fs) end proc

ode1 := L*(diff(i(t), t))+v(t) = square_wave_periodic
ode2 := C*(diff(v(t), t))+v(t)/R = i(t)
IC := v(0) = 0, i(0) = 0
sol := dsolve({IC, ode1, ode2}, {i(t), v(t)}, numeric)

LCRcircuit_transient_numerical.mw

Any help is much appreciated ! Thank you !

Good day. 

I have been looking into the time series features in Maple and was eager to apply the models to one specific example containing 47 data points (attached).

When I run the ESM routine, Maple provides a forecast based on a (A,N,N) configuration. You will notice that the forecast for the following 12 data points is a constant value. I have also noticed this for several other data set examples and I would have expected the predictions to vary across the next 12 data points.

Does the (A,N,N) configuration in Maple automatically provide an optimal forecast and can anyone advise me on how to specify all possible combinations of (error, trend, season) models?

Thanks you for reading.

MaplePrimes_TS_Example.mw

solve((∂(-    ∇(f) ))/(∂ t)+((DotProduct(v[0],∇f))*(1-e(DotProduct(B,Omega)))+(c[s0]^(2)*rho[1])/(rho[0])(1-e(DotProduct(B,Omega)))+e(CrossProduct(∇ f,B))*Omega-e((DotProduct(-∇f,Omega))*(DotProduct(B,∇)))*(-∇f)+e(E)*(1-(DotProduct(B,Omega)))+e^(2)(DotProduct(E,B))*Omega-e*((CrossProduct(E,Omega))*(∇(-∇f)),rho[1]);

lis := SearchSmallGroups('order' = 10 .. 100, 'soluble'): 
seq(DrawSubgroupLattice(SmallGroup(g), 'highlight' = CompositionSeries(SmallGroup(g))), g in lis[10 .. 20])

I want to see if these red nodes are present in each layer and connected at each level, so I need to detect a large number of images. But if I put them in the same row, these images will be very small and I have to zoom in one by one with the mouse to see them. How can I set the size of these images?

ps：I'm currently using my eyes to determine if these red nodes are present at each layer and connected at each level, and I'd be happy if there was code to do this

I want to do some memory management in Maple for large arrays.

To clarify this question: What do I have to do in Maple to free memory allocated to an array? The indications I have are that memory probably is not freed, but rather a new variable of null is created that replaces the old one, but the old one is still sitting around.

Is this a bug?

I was cleaning my code using mint. It told me that

             These names were used as global names but were not declared:  right

which is the direction used in a limit. When this happens, I just replace the name with 'right' to make it happy. This works for everything so far. But now limit fails with

      Error, (in assuming) when calling 'limit'. Received: 'invalid directional argument'

the strange thing this happens only when adding assuming after the limit.

It seems to me to be some parsing issue?  Attached is worksheet showing the problem.

Maple 2022.2 on windows 10. So for now I will remove the '' and let mint just complain.

Download issue_with_limit_oct_31_2022.mw

Hi,

Since a couple of years ago,  SQLite has been enriched with a bunch of new math functions not existing in previous versions: acos, asin, atan, atn2, atan2, acosh, asinh, atanh, difference, degrees, radians, cos, sin, tan, cot, cosh, sinh, tanh, coth, exp, log, log10, power, sign, sqrt, square, ceil, floor, pi. 

Examples: In SQLite version 3.39.4 2022-09-29 15:55:41 we can invoke:

sqlite> select pi();
3.14159265358979

sqlite> select power(2, 3);
8.0

sqlite> select floor(2.35);
2.0

Package Database[SQLite] in Maple 2022.2 does not recognize these functions.

In oldest versions of Sqlite3 we were able to add these functions after loading an external extension with sqlite3 api function load_extension() (see  https://sqlite.org/contrib/download/extension-functions.c), but his option is blocked in Maple:

dbName := "d:/sq3_maple/etc.db":
sq3Extension := "d:/sq3_maple/extensions.sq3":

with(Database[SQLite]);
[Attach, Bind, ClearBindings, Close, ColumnCount, ColumnNames, 
  Execute, Fetch, FetchAll, FetchRow, Finalize, Open, Opened, 
  Prepare, RESULT_BUSY, RESULT_DONE, RESULT_ROW, Reset, Step]

conn := Open(dbName):
Execute(conn, sprintf("SELECT load_extension('%s')", sq3Extension));
Error, (in Database:-SQLite:-Execute) not authorized

Am I missing something? Any way to add these functions to SQLite in current version of Maple?

Thanks in advance.

César Lozada

PS: SQLite is updated in Mathematica 13.1

is a typical example of Maple output (in this case the natural frequency of a harmonic oscillator with m>0) where further simplification to text book notation is desired.

To get

the context menu did not help. On the command level, combine,radical (which I assumed is suitable) was also not effective.

Is there a better way to achieve the desired simplification than the one (found by trial and error) in the attachment?

If there is no better way: Would it make sense to improve the combine or any other command for such a case?

combining_radical.mw

How can these eight equations q[0]...q[7] be solved for the eight unknowns a1[0]...a1[7] and with the lowest CPU time

11.mw

Hello,

I use Maple and Maple Flow and want to work with physical units. However, I am quickly reaching the limits of what is possible. Now the question: Would it be possible to work with units and the piecewise function? In the attached example, the integration of a defined function is no longer possible. Or should I proceed differently in principle? Many thanks for any advice

Clemens

Download UnitProblem.mw

Hi, so I'm trying to solve this equation, but it seems that I've ran into two issues with it:

My problems with this this is such:

• The pi^2 did not get integrated into the solution, it's just a pi^2. I would rather it not be like that, but the actual resulting number from that division
• The units should result in Ω, but it's not, instead it just added the units from the original variables. How do I make it set to the "correct" unit?

LLC_converter.mw

Dear all

I construct by hand the two matrices L and U so that A= LU ( LU-factorization) 
I would like to find the number of arithmetic operations required to obtain the matrices 𝐿 and 𝑈

Number_arithmetic_operation.mw

Thank you