nm

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These are questions asked by nm

Wondering what the experts here think of this. Should not simplify have worked on this automatically? By trial and error, found that combine command is what simplified it the best.

But I think simplify should also have done the same.  

Interested to hear what others think, and why simplify (even using trig option) did not do it.   

The issue is that this is done in code, without lookin at the screen and deciding what to do based on what the expression "looks like".

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

A:=(((sin(sqrt(3)/2)*sqrt(3) - 3*cos(sqrt(3)/2))*cos(sqrt(3)*x/2) - sin(sqrt(3)*x/2)*(sqrt(3)*cos(sqrt(3)/2) + 3*sin(sqrt(3)/2)))*exp(-1/2 + x/2))/3 ;

(1/3)*((sin((1/2)*3^(1/2))*3^(1/2)-3*cos((1/2)*3^(1/2)))*cos((1/2)*3^(1/2)*x)-sin((1/2)*3^(1/2)*x)*(3^(1/2)*cos((1/2)*3^(1/2))+3*sin((1/2)*3^(1/2))))*exp(-1/2+(1/2)*x)

B:=- exp(-1/2 + x/2)*(sqrt(3)*sin(sqrt(3)*(x - 1)/2) + 3*cos(sqrt(3)*(x - 1)/2))/3;

-(1/3)*exp(-1/2+(1/2)*x)*(3^(1/2)*sin((1/2)*3^(1/2)*(x-1))+3*cos((1/2)*3^(1/2)*(x-1)))

simplify(A-B); #show these are same

0

simplify(A,trig)

-(1/3)*((-sin((1/2)*3^(1/2))*3^(1/2)+3*cos((1/2)*3^(1/2)))*cos((1/2)*3^(1/2)*x)+sin((1/2)*3^(1/2)*x)*(3^(1/2)*cos((1/2)*3^(1/2))+3*sin((1/2)*3^(1/2))))*exp(-1/2+(1/2)*x)

simplify(A)

-(1/3)*((-sin((1/2)*3^(1/2))*3^(1/2)+3*cos((1/2)*3^(1/2)))*cos((1/2)*3^(1/2)*x)+sin((1/2)*3^(1/2)*x)*(3^(1/2)*cos((1/2)*3^(1/2))+3*sin((1/2)*3^(1/2))))*exp(-1/2+(1/2)*x)

simplify(A,size)

-(1/3)*((-sin((1/2)*3^(1/2))*3^(1/2)+3*cos((1/2)*3^(1/2)))*cos((1/2)*3^(1/2)*x)+sin((1/2)*3^(1/2)*x)*(3^(1/2)*cos((1/2)*3^(1/2))+3*sin((1/2)*3^(1/2))))*exp(-1/2+(1/2)*x)

simplify(normal(A))

-(1/3)*((-sin((1/2)*3^(1/2))*3^(1/2)+3*cos((1/2)*3^(1/2)))*cos((1/2)*3^(1/2)*x)+sin((1/2)*3^(1/2)*x)*(3^(1/2)*cos((1/2)*3^(1/2))+3*sin((1/2)*3^(1/2))))*exp(-1/2+(1/2)*x)

combine(A); #finally

(-(1/3)*3^(1/2)*sin((1/2)*3^(1/2)*(x-1))-cos((1/2)*3^(1/2)*(x-1)))*exp(-1/2+(1/2)*x)

 

 

Download simplify_vs_combine_june_4_2025.mw

This could be unrelated to V 26 of support tools and it could be a bug that existed in Maple before.

But no time for me to check now. Thought to ask about it before I forget.

When adding Physics:-Setup('assumingusesAssume'=true):  Maple generated internal error that can not be cought.

This is using latest V 26 of support tools

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1873 and is the same as the version installed in this computer, created 2025, May 18, 21:44 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 26 and is the same as the version installed in this computer, created June 3, 2025, 23:49 hours Eastern Time.`

restart;

ode:=diff(y(x),x) = (ln(y(x))^2+2*_C1)^(1/2)*y(x);
sol:=y(x) = exp((-2*_C1)^(1/2));
try
   timelimit(30,(odetest(sol,ode) assuming positive));
catch:
   print("cought error ok");
end try;

diff(y(x), x) = (ln(y(x))^2+2*_C1)^(1/2)*y(x)

y(x) = exp((-2*_C1)^(1/2))

-(ln(exp(I*2^(1/2)*_C1^(1/2)))^2+2*_C1)^(1/2)*exp(I*2^(1/2)*_C1^(1/2))

restart;

ode:=diff(y(x),x) = (ln(y(x))^2+2*_C1)^(1/2)*y(x);
sol:=y(x) = exp((-2*_C1)^(1/2));
Physics:-Setup('assumingusesAssume'=true):
try
   timelimit(30,(odetest(sol,ode) assuming positive));
catch:
   print("cought error ok");
end try;

diff(y(x), x) = (ln(y(x))^2+2*_C1)^(1/2)*y(x)

y(x) = exp((-2*_C1)^(1/2))

Error, (in type/complex) too many levels of recursion

 

 

Download type_complex_recursion_june_4_2025_V26_support.mw

I was debugging another Maple problem and found this.

According to help, it says

Computations performed using assuming do not affect computations performed before or after calling assuming.

But this example below shows this is not the case at all.

I used hasassumptions(y(x)); before calling a command that uses assuming, and it gave false as expected since there are no assumption put on y(x).

After the command is complete, now I find that  hasassumptions(y(x)); returns true  which is wrong. 

This only happens when adding Physics:-Setup('assumingusesAssume'=true); and also when the command that uses assuming timesout.

But from help, this should not cause this. Here is the help on this

assumingusesAssume
  true or false.

The default for this option is true, so that, when Physics is loaded, the Maple assuming command uses Physics:-Assume to place temporary assumptions. This makes the assuming command fully compatible with the Physics, DifferentialGeometry, DifferentialAlgebra and VectorCalculus packages. It is recommended to not change this setting. If assumingusesAssume is set to false, temporary assumptions placed by assuming are placed using the assume command, which redefines the variables receiving assumptions, so that, depending on the computation, the commands of these packages mentioned will fail in recognizing them within expressions (for example: when placing assumptions on the coordinates and computing with the spacetime metric).

Could someone please explain in very simple terms (as I find all this very confusing), why that after calling a command which uses assuming, I find my variables have assumption still attached to them? 

Because of this, commands that uses these variables after this will and could fail depending on what command is used.

This explains many of the problems I am seeing when using assuming command.  

My question is simple: Should any variable which did not have assumptions on it, still not have assumptions on it after using assuming regadless if the command that uses assuming timedout or not?

Notice that I am not even using the Physics package explicitly anywhere in the following. I am just called odetest with timeout.

Here is worksheet to illustrate this.

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1873 and is the same as the version installed in this computer, created 2025, May 18, 21:44 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 23 and is the same as the version installed in this computer, created June 2, 2025, 12:08 hours Eastern Time.`

restart

 

#this shows no assumptions on y(x);
ode:=y(x)*sqrt(1 + diff(y(x), x)^2) - a*y(x)*diff(y(x), x) - a*x = 0:
sol:=-_C4^2 + (-y(x)*sqrt(_C4^2/y(x)^2) + a*x)^2/a^2 + y(x)^2 = 0;
hasassumptions(y(x));
getassumptions(y(x));

-_C4^2+(-y(x)*(_C4^2/y(x)^2)^(1/2)+a*x)^2/a^2+y(x)^2 = 0

false

{}

#now use a command that uses assuming
Physics:-Setup('assumingusesAssume'=true):
timelimit(10,(odetest(sol,ode,y(x)) assuming integer)):

Error, (in simplify/sqrt/local) time expired

 

#this shows that y(x) has assumptions still stuck on it.

hasassumptions(y(x));
getassumptions(y(x));

true

{a::integer, x::integer, (-(-csgn(1/y(x))*a*x+(y(x)^2*a^4+csgn(1/y(x))^2*a^2*x^2+a^4*x^2-y(x)^2*a^2-a^2*x^2)^(1/2))/(a^2-1)+x)::0, ((csgn(1/y(x))*a*x-(y(x)^2*a^4+csgn(1/y(x))^2*a^2*x^2+a^4*x^2-y(x)^2*a^2-a^2*x^2)^(1/2))/(a^2-1)-x)::0, ((csgn(1/y(x))*a*x+(y(x)^2*a^4+csgn(1/y(x))^2*a^2*x^2+a^4*x^2-y(x)^2*a^2-a^2*x^2)^(1/2))/(a^2-1)-x)::0, ((csgn(1/y(x))*a*x+(y(x)^2*a^4+csgn(1/y(x))^2*a^2*x^2+a^4*x^2-y(x)^2*a^2-a^2*x^2)^(1/2))/(a^2-1)+x)::0}

 

 

Download why_variable_have_assumption_june_3_2025.mw

My quess is this: Because the command that uses assuming timedout, Maple failed to remove/clear any temporary assumptions it added to the variables involved.   But this only happens when using Physics:-Setup('assumingusesAssume'=true):

If the command did not timeout, this does not happen. At least on some examples I tried this on.

After updating to V 22 of supportTools, I found a new error.

This works sheet using V 22 gives this

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1873 and is the same as the version installed in this computer, created 2025, May 18, 21:44 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 22 and is the same as the version installed in this computer, created May 28, 2025, 23:36 hours Eastern Time.`

restart;

IC:=y(2) = 2;
ode:=diff(y(x),x) = (x-y(x))^(1/2);
sol:=y(x) = -(LambertW(-exp(-1/2*x))+1)^2+x;

y(2) = 2

diff(y(x), x) = (x-y(x))^(1/2)

y(x) = -(LambertW(-exp(-(1/2)*x))+1)^2+x

odetest(sol,ode) assuming positive;

Error, (in property/AndProp/+) too many levels of recursion

odetest(sol,[ode,IC]) assuming positive;

Error, (in AndProp:-UseCache) too many levels of recursion

 

 

Download bug_in_odetest_with_lambertW_june_2_2025.mw

But same code works OK in V 21

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1873 and is the same as the version installed in this computer, created 2025, May 18, 21:44 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 22. The version installed in this computer is 21 created May 28, 2025, 23:36 hours Eastern Time, found in the directory /home/me/maple/toolbox/2025/Maple Customer Support Updates/lib/Maple`

IC:=y(2) = 2;
ode:=diff(y(x),x) = (x-y(x))^(1/2);
sol:=y(x) = -(LambertW(-exp(-1/2*x))+1)^2+x;

y(2) = 2

diff(y(x), x) = (x-y(x))^(1/2)

y(x) = -(LambertW(-exp(-(1/2)*x))+1)^2+x

odetest(sol,ode) assuming positive;

-csgn(LambertW(-exp(-(1/2)*x))+1)*LambertW(-exp(-(1/2)*x))-csgn(LambertW(-exp(-(1/2)*x))+1)+LambertW(-exp(-(1/2)*x))+1

odetest(sol,[ode,IC]) assuming positive;

[-csgn(LambertW(-exp(-(1/2)*x))+1)*LambertW(-exp(-(1/2)*x))-csgn(LambertW(-exp(-(1/2)*x))+1)+LambertW(-exp(-(1/2)*x))+1, 0]

 

 

Download no_bug_in_odetest_with_lambertW_june_2_2025.mw

This is not a big deal, but I was wondering why it changed. Before, after doing SupportTools:-Version(latest); to get latest version, the message used to say to just do restart; to use the new version of SupportTools (i,e. no need to close all of Maple). (I remember this, but I have no screen shot now to show this old message). I always used to just do restart; and it always worked.

Now, with version 22, the message changed, it now says to close and restart all of Maple

Why this change happened?  

Maple 2025 on Linux

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