Maple Questions and Posts

RE: PropsSI - steam table entries ...

Asked by: pik1432 245

January 11 2022

2 5

Hello there,

Would you allow me to ask one question?

Is there any way to get a saturated water vapor pressure value with a temperature outside of the range?

The range here means [273.06 K, 647.096 K]. The pressure value certainly exists (T<273.06 K), but the API only comes up with an error.

Here is the Maple worksheet where I got into this issue:

>

restart;

>	with(ThermophysicalData):

>	with(CoolProp):

>	with(Units[Standard]):

>	with(ScientificConstants):

>	T2 := (-40.0 + 273.15) * Unit('K');

(1)

>	xbb := 1: # 100% steam, saturated.

>	Pg2 := PropsSI("P", "T", T2, "Q", xbb, "water");

Error, (in ThermophysicalData:-CoolProp:-PropsSI) Temperature to QT_flash [233.15 K] must be in range [273.06 K, 647.096 K] : PropsSI("P","T",233.15,"Q",1,"water")

>

Download Q20220111.mw

How to plot the approximation graph for the primes...

Asked by: janhardo 700

January 10 2022

1 1

I must feed the not trivial zeros numbers into this aproximation formula ?

Riemann hypothese and staircase of primes

>

restart;

>

(1)

>

(2)

>

(3)

>

(4)

The prime counting function is approximated by and .

>

The staircase of primes approximated by two functions
Interesting is the video: How i learned to love and fear the Riemann Hypothesis

https://www.quantamagazine.org/how-i-learned-to-love-and-fear-the-riemann-hypothesis-20210104/

>

>	ps:=Array(1..30): y:=0: for n from 1 to 30 do if is(n,prime) then ps[n]:=plot([[n,y],[n,y+1],[n+1,y+1]]): y:=y+1; else ps[n]:=plot([[n,y],[n+1,y]]): end if ; od; with(plots): display({seq(ps[n],n=1..30)}):

>	plot([PrimeCounting(x)] ,x = 1 .. 35, legend = [pi(x)]):

>

Prime counting function
What found RIEMANN for the prime counting function in relation to the zeta function after he defined the zeta function?

He found further a function what follows exactly the shape of the prime counting function

Final discovery v. Riemann.

- step in the omhoog in de priemtelfunctie = log(p) (zie video)

Using the logarithmic primecount function( from Chebyshev) (approximation)
Further analyse with this Chebyshev approximation formula in relation to the not trivial zero points from Riemann zeta function ( zeros) gives another real function for approximating the primecounting function what uses the non trivial zeros from Riemanns zeta function in this function:

Number now all nottrivial zeros in the upperhalfplane from down to bottom, as

>

"`ϕ`(x) := x-ln(2Pi)-1/(2 )ln(1-1/(x^(2))) - (∑)2/(|u[k]|) x^(v[k]) cos(w[k] ln(x)-alpha[k])"

>

Its only that must be calculated out of the not trivial zeros and i must have a list of serie of not trivial zeroes from the zeta function. => see Hardy's Z(t) ? from this ..... can be calculated ?
All not trivial zeros are complex numbers laying on a line ,but orginating from (0,0) in the complex plane as vectors to the points

>	varphi(x):= x - ln(2Pi) - 1/2ln(1 - 1/x^2) - sum(2x^v[k]cos(w[k]*ln(x) - alpha[k])/abs(u[k]), k = 1 .. infinity);

x-ln(2*Pi)-(1/2)*ln(1-1/x^2)-(sum(2*x^v[k]*cos(-w[k]*ln(x)+alpha[k])/abs(u[k]), k = 1 .. infinity))

(5)

This formula seems to be correct .
Now how to make a plot ?
Hardy's Z(t) function shows the not trivial zeros in the upperhalfplane of the critical strip of the Riemann zeta function as zeros in this Z(t) real function : derived from a alternating serie ?

Download priem_staircase_en_riemann_functie.mw

Unexpected bug in solve...

Asked by: vv 13847

January 07 2022

4 1

It's sad when a bug is found for such a simple problem!

sys := [x*y*z = 0, x*y*z + x*z + z = 0, x*y*z + x*y + x = 0]:
solve(sys, {x,y,z});    # OK
#         {x = 0, y = y, z = 0}, {x = x, y = -1, z = 0}

solve(sys, [x,y,z]);    # ???
#                               []

Document Section Numbering and header layouts...

Asked by: wswain 240

January 06 2022

1 0

Hi,

Happy New Years All

Can anyone explain two document formating features I am trying to implement?

1.) Sections. I select numbering with follow previous selected and I get three sections with a 1. in front of them vs 1, 2, 3.

I would expect Technical to become 3.1 when properly following Section 3. header. Also, I have seen how to manually type the section number, but that seems to defeat the document layout and formatting if it gets "jumbled up".

2.) Headers. Can you suppress headers on pages 2 through X to have a unique cover page header? This would be similar to word (headers and footers linked to previous section, or not(?) with section breaks as new pages)

Thanks,
Bill

array in proc doesnt sub the values ...

Asked by: olawattad 80

January 03 2022

1 1

hello
i have a long proc i am defining in a loop inside the proc for some reason it calculates the value of a1[j+1] and a2[j+1] and assigns it(in the case of the picture j=1 and in j=2 it doesnt sub) but when it is called again in the next iteration it doesnt sub the value it just calcluated !
i would be so thankful for any help ive been stuck on this for a while now

Cloud Verson of Syrup not loaded in Emacs...

Asked by: Thomas Dean 327

January 03 2022

1 0

I installed the cloud version of Syrup with xmaple, by clicking the cloud icon, etc. It is loaded with xmaple and cmaple. But, not in maple running in emacs.

with(Syrup);
(**) Error, invalid input: with expects its 1st argument, pname, to be of type
{module, package}, but received Syrup
(**)

Tom Dean

Why one needs to give full name on local type decl...

Asked by: nm 11363

December 30 2021

1 0

In this example, i have a top module A. Inside it, I have module named my_RECORD (which happened to be option object) that I want to return back to caller when they call a proc.

Maple allows me to declare the proc to return my_RECORD. No problem., But when making a local variable inside the proc and using o::my_RECORD it complains that my_RECORD does not exist.

The solution is to change o::my_RECORD to o::A:-my_RECORD

My question why it did not complain the same way on the return value on the proc? for me, they are both semantically the same. One says the proc returns this type, and the other says the local variable is this type. So why had to do A:-my_RECORD on one but not the other?

Here is an example. Maple 2021.2 on windows 10.

>

restart;

>	interface(warnlevel=4); kernelopts('assertlevel'=2):

>

A:=module()
#this is the RECORD to return
  local module my_RECORD()
   option object;
   export data::string:="";
  end module;

  export do_analysis:=proc()::my_RECORD;
    local o::my_RECORD; #error here. But this is the same above line above?
    o:=Object(my_RECORD);
    o:-data:="test";
    return o;
  end proc;
end module;

>	A:-do_analysis()

Error, (in do_analysis) type `my_RECORD` does not exist

>	#FIXED BELOW restart;

>

A:=module()
    #this is the RECORD to return
    local module my_RECORD()
        option object;
        export data::string:="";
    end module;

    export do_analysis:=proc()::my_RECORD;
          local o::A:-my_RECORD;
          o:=Object(my_RECORD);
          o:-data:="test";
          return o;
    end proc;
end module;

>	A:-do_analysis()

>

Download A_no_lib.mw

Exporting a diagram...

Asked by: dholtzman 105

December 28 2021

2 4

I often create diagrams in Maple and export them so I can embed them in a Word Doc. Lately, when I right-click on the picture so I can select "export," the entire program closes. It seems to happen more when the picture is in 3D. Am I doing something wrong? Thanks.

David

Error in the documentation of the Physics Package ...

Asked by: Kevin Dragnet 140

December 24 2021

3 4

Hi, I am trying to enter into the Mini-Course Computer Algebra for Physicists from the help, but instead of going to the page I get the help page of Physics[FeynmanIntegral]. Can anyone confirm that this happens to them on Maple 2021.2?

Kevin

Student[ODEs][ODESteps]: simple pendulum not suppo...

Asked by: C_R 3437

December 21 2021

1 4

But ODEsteps supports simliar ODEs (see attached).
Is the ODESteps command not generic enough to cover the pendulum or have I missed something?

ODESteps.mw

Workbook move files impossible in 2021.2...

Asked by: Anthrazit 885

December 16 2021

1 3

I can't move files in the navigator window anymore in Maple 2021.2.

Anyone else with the same problems?

why use static for Objects?...

Asked by: nm 11363

December 15 2021

2 0

Other than saving few bytes of memory, why would one use ::static for methods of Object?

I found that if I use ::static, then I have to add prefix _self:- each time an object data member is referenced anywhere, making the code very hard to read.

Imagine having to write _self:-x + 3* _self:-x^2 + 2* _self:-y^3 and so on all the time, instead of just x+3*x^2+2*y^3. (where it is assumed here that x,y happened to be object private data members and not local variables for a proc inside the module).

But then I found if I remove ::static now _self:- no longer needed and can still get the benefit of using the object and the code works as before, but the code is now much more readable.

I know that by not using static, then a copy of each method is made for each new object.

I am OK with that. As I do not use that many objects any way (few at a time before GC cleans the ones I used).

But the benefit of much more readable code far outweights the little extra memory needed, and memory is cheap these days anyway. I got lots of RAM. An extra few MB's is not a big deal.

What Am I missing here? Why does all the Maple help and documenation say that one should use static for object methods then? But do not mention that by not using static:: then the code will become more readable since _self:- is not needed to be appeneded to each variable or method name.

Here is an example below to compare.

First example uses ::static methods, and the second does not.

One can see the difference The code is more clear in the second. Is there something else I am overlooking by not using ::static . I am still learning OOP in Maple, and could be overlooking something else. I definitly do not want to code using _self:-variable_name all the time if I have to use OOP in Maple as it makes the code hard to read.

Notice that in both examples, and for the exported methods, I used _self as first argument. This is OK. This is meant to allow client of the object to call it using object:-method() syntax which is what I prefer instead of method(object,....). syntax.

I am talking about the execssive use of _self internal to the module/object code when having to use ::static. methods.

>

restart;

>

person_class_STATIC:=module()
   option object;
   local age:=5;

   export set_age::static:=proc(_self,age,$)
     _self:-age:=age:
   end proc:

   export update_age::static:=proc(_self,age,$)
      do_the_update(_self)
   end proc:

   local do_the_update::static:=proc(_self,$)
      _self:-age:=_self:-age+1;
      _self:-age:=sqrt(_self:-age^2+3);
   end proc;

   export get_age::static:=proc(_self,$)
     return _self:-age;
   end proc:

end module:

>	o:=Object(person_class_STATIC); o:-set_age(100); o:-get_age(); o:-update_age(); o2:=Object(person_class_STATIC); o2:-get_age();

>

person_class_NO_STATIC:=module()
   option object;
   local age:=5;

   export set_age:=proc(_self,_age,$)
     age:=_age:
   end proc:

   export update_age:=proc(_self,$)
      do_the_update()
   end proc:

   local do_the_update:=proc()
      age:=age+1;
      age:=sqrt(age^2+3);
   end proc;

   export get_age:=proc(_self,$)
     return age;
   end proc:

end module: