## 9794 Reputation

12 years, 66 days

## Problem using smart plot with multiple ...

Maple 2024

I switched to using smart plot in Maple since it makes it easier. Here is an example

sol:=[-1/4*x^2, x];
plot(sol,legend=sol)


But sometimes it gives internal error, like in this example, because some of the list of solutions give complex over some x domain

sol:=[-1/4*x^2, (-1/2-1/2*(-3)^(1/2))^2+(-1/2-1/2*(-3)^(1/2))*x, (-1/2+1/2*(-3)^(1/2))^2+(-1/2+1/2*(-3)^(1/2))*x];
plot(sol,legend=sol)


Luckily I can trap this error and workaround it.

The strange thing is that if I give it explicit x range, then it works. It now can remove the solutions which give complex values automatically

p:=plot(sol,x=-4..4,legend=sol);


question is: Should not smart plot have done this automatically? That is why it is called smart plot.

i.e. remove those solutions that give complex values like the case the above?

Maple 2024.1 on windows 10

## why maple hangs on this plot command?...

Maple 2024

I am using the smart plot (i.e plot without giving the x=from..to) since I am generating these plots programmatically and better let Maple figure the best range to use.

But found Maple hangs on some solutions.

Here is an example

restart;
sol:=1/2/cos(x)*(sin(x)^2+(sin(x)^4+36*cos(x))^(1/2));
plot(sol);


I waited for 30 minutes and nothing happened.

If I change the above command to

plot(sol,x=-Pi..Pi);

then it finishes instantly. It looks like Maple is stuck trying to find correct x and y ranges to use.

Is this known limitation  or smart plot or is this a bug?

Maple 2024.1 on windows 10.

## what causes kernel connection not avail...

Maple 2024

sometimes (not often) I get this pop-up window when I open new worksheet and run something first time in it.

And it can last for 10-20 seconds until connection is made.

I have my preferences set to  create new engine for each worksheet.

The strange thing when this happened now, is that I only had 4 worksheets open and was not running anything in any of them. So Maple was not "busy". Task manage showed 8 mservers.exe processes on it at the time. Which is not unormal.

I have 128 GB and PC was not busy at the time this happened.

Any idea what can cause this to happen?

Windows 10 home edition, Maple 2024.1

## How to obtain the extent of the x and y ...

Maple 2024

When making this plot, using smart plot (i.e. not giving the plot command the x=from..to and also not giving it y=from...to

p:=plot(0,color=red);

I need to programatically find the x=-10..10 and y=-1..1 from the variable p. But if I do

rhs~(indets(p, identical("originalview")=anything));

it gives

{[-10. .. 10., 0. .. 0.]}

But clearly looking at the plot the y axis is from -1..1

The reason I need to determine the view from the above plot, is that I need to use same view windows size in another plot not using smart plot (phase plot) which requires one to provide explicit x and y ranges. i.e I'd like the phase plot to have same view size in terms of x range and y range.

I printed the PLOT structure but do not see another field to look at.

Any idea or trick to find y=-1..1 values in this example ? I am using Maple 2024.1

lprint(p)
PLOT(CURVES(Matrix(200,2,{(1, 1) = -10., (2, 1) = -9.89484789949749, (3, 1) =
-9.80335561909548, (4, 1) = -9.70046298090452, (5, 1) = -9.59688830351759, (6,
1) = -9.49380589849246, (7, 1) = -9.39823531356784, (8, 1) = -9.29927750854271,
(9, 1) = -9.19693520502513, (10, 1) = -9.09492111457286, (11, 1) =
-8.98998708341709, (12, 1) = -8.89756113165829, (13, 1) = -8.79351140100503, (
14, 1) = -8.6890344321608, (15, 1) = -8.58835151356784, (16, 1) =
-8.49692177788945, (17, 1) = -8.38820297889447, (18, 1) = -8.29610389547739, (
19, 1) = -8.18897076683417, (20, 1) = -8.09413979497487, (21, 1) =
-7.99009518894472, (22, 1) = -7.89102011959799, (23, 1) = -7.78764567839196, (
24, 1) = -7.69271567135678, (25, 1) = -7.59032083417085, (26, 1) =
-7.4839613758794, (27, 1) = -7.39137515477387, (28, 1) = -7.29137949949749, (29
, 1) = -7.18807420301508, (30, 1) = -7.08701012462312, (31, 1) =
-6.9892254321608, (32, 1) = -6.88065220301508, (33, 1) = -6.78309432763819, (34
, 1) = -6.67893047236181, (35, 1) = -6.58454253768844, (36, 1) =
-6.48135159396985, (37, 1) = -6.38425695778894, (38, 1) = -6.28276508643216, (
39, 1) = -6.18353823115578, (40, 1) = -6.07965690954774, (41, 1) =
-5.97960685025126, (42, 1) = -5.87729121407035, (43, 1) = -5.77582280301507, (
44, 1) = -5.68258387135678, (45, 1) = -5.57572153366834, (46, 1) =
-5.48014258492462, (47, 1) = -5.37823549045226, (48, 1) = -5.28069739798995, (
49, 1) = -5.17239388140703, (50, 1) = -5.07861099396985, (51, 1) =
-4.97216657788945, (52, 1) = -4.87515404824121, (53, 1) = -4.76903758693467, (
54, 1) = -4.67747702713568, (55, 1) = -4.57320023718593, (56, 1) =
-4.47247400603015, (57, 1) = -4.37181357688442, (58, 1) = -4.27152345929648, (
59, 1) = -4.17517605326633, (60, 1) = -4.07102195577889, (61, 1) =
-3.97175554874372, (62, 1) = -3.86728232964824, (63, 1) = -3.77270890854271, (
64, 1) = -3.66818757386935, (65, 1) = -3.56807434874372, (66, 1) =
-3.46820480201005, (67, 1) = -3.36389067336683, (68, 1) = -3.26781355276382, (
69, 1) = -3.16941743919598, (70, 1) = -3.06077643819095, (71, 1) =
-2.96241091055276, (72, 1) = -2.86181373366834, (73, 1) = -2.7595089959799, (74
, 1) = -2.66547103417085, (75, 1) = -2.5652296120603, (76, 1) =
-2.46575123417085, (77, 1) = -2.35934029145729, (78, 1) = -2.26543724422111, (
79, 1) = -2.15709262110553, (80, 1) = -2.05931995175879, (81, 1) =
-1.96257900603015, (82, 1) = -1.85855141105528, (83, 1) = -1.75410300301508, (
84, 1) = -1.65907041708543, (85, 1) = -1.5581500321608, (86, 1) = -1.4596616, (
87, 1) = -1.35289910050251, (88, 1) = -1.26051985527638, (89, 1) =
-1.15441893366834, (90, 1) = -1.05467848944724, (91, 1) = -.955901429145728, (
92, 1) = -.857045790954773, (93, 1) = -.756219297487437, (94, 1) =
-.649344903517589, (95, 1) = -.551351549748743, (96, 1) = -.454619526633167, (
97, 1) = -.351214585929648, (98, 1) = -.248034748743718, (99, 1) =
-.155424717587939, (100, 1) = -.0457214572864313, (101, 1) = .0460731437185924,
(102, 1) = .153437240201004, (103, 1) = .255905869346734, (104, 1) =
.347398149748743, (105, 1) = .4502907879397, (106, 1) = .553865465326634, (107,
1) = .656947870351759, (108, 1) = .752518455276382, (109, 1) = .851476260301508
, (110, 1) = .953818563819095, (111, 1) = 1.05583265427136, (112, 1) =
1.16076668542714, (113, 1) = 1.25319263718593, (114, 1) = 1.3572423678392, (115
, 1) = 1.46171933668342, (116, 1) = 1.56240225527638, (117, 1) =
1.65383199095477, (118, 1) = 1.76255078994975, (119, 1) = 1.85464987336683, (
120, 1) = 1.96178300201005, (121, 1) = 2.05661397386935, (122, 1) =
2.1606585798995, (123, 1) = 2.25973364924623, (124, 1) = 2.36310809045226, (125
, 1) = 2.45803809748744, (126, 1) = 2.56043293467337, (127, 1) =
2.66679239296482, (128, 1) = 2.75937861407035, (129, 1) = 2.85937426934673, (
130, 1) = 2.96267956582914, (131, 1) = 3.06374364422111, (132, 1) =
3.16152833668342, (133, 1) = 3.27010156582915, (134, 1) = 3.36765944120603, (
135, 1) = 3.47182329648241, (136, 1) = 3.56621123115578, (137, 1) =
3.66940217487437, (138, 1) = 3.76649681105528, (139, 1) = 3.86798868241206, (
140, 1) = 3.96721553768844, (141, 1) = 4.07109685929648, (142, 1) =
4.17114691859297, (143, 1) = 4.27346255477387, (144, 1) = 4.37493096582915, (
145, 1) = 4.46816989748744, (146, 1) = 4.57503223517588, (147, 1) =
4.6706111839196, (148, 1) = 4.77251827839196, (149, 1) = 4.87005637085427, (150
, 1) = 4.97835988743719, (151, 1) = 5.07214277487437, (152, 1) =
5.17858719095477, (153, 1) = 5.27559972060302, (154, 1) = 5.38171618190955, (
155, 1) = 5.47327674170854, (156, 1) = 5.57755353165829, (157, 1) =
5.67827976281407, (158, 1) = 5.7789401919598, (159, 1) = 5.87923030954774, (160
, 1) = 5.97557771557789, (161, 1) = 6.07973181306533, (162, 1) =
6.1789982201005, (163, 1) = 6.28347143919598, (164, 1) = 6.37804486030151, (165
, 1) = 6.48256619497488, (166, 1) = 6.5826794201005, (167, 1) =
6.68254896683417, (168, 1) = 6.78686309547739, (169, 1) = 6.8829402160804, (170
, 1) = 6.98133632964824, (171, 1) = 7.08997733065327, (172, 1) =
7.18834285829146, (173, 1) = 7.28894003517588, (174, 1) = 7.39124477286432, (
175, 1) = 7.48528273467337, (176, 1) = 7.58552415678392, (177, 1) =
7.68500253467337, (178, 1) = 7.79141347738694, (179, 1) = 7.88531652462311, (
180, 1) = 7.9936611477387, (181, 1) = 8.09143381708543, (182, 1) =
8.18817476281407, (183, 1) = 8.29220235778895, (184, 1) = 8.39665076582915, (
185, 1) = 8.49168335175879, (186, 1) = 8.59260373668342, (187, 1) =
8.69109216884422, (188, 1) = 8.79785466834171, (189, 1) = 8.89023391356784, (
190, 1) = 8.99633483517588, (191, 1) = 9.09607527939699, (192, 1) =
9.1948523396985, (193, 1) = 9.29370797788945, (194, 1) = 9.39453447135678, (195
, 1) = 9.50140886532663, (196, 1) = 9.59940221909548, (197, 1) =
9.69613424221106, (198, 1) = 9.79953918291458, (199, 1) = 9.9027190201005, (200
, 1) = 10.},datatype = float[8],storage = rectangular,order = Fortran_order,
shape = []),COLOUR(RGB,.47058824,0.,.54901961e-1,_ATTRIBUTE("source" =
"mathdefault"))),AXESLABELS("",""),VIEW(-10. .. 10.,DEFAULT,_ATTRIBUTE("source"
= "mathdefault")),_ATTRIBUTE("input" = [table([(1)=plot,(2)=[0]]),
"originalview" = [-10. .. 10., 0. .. 0.], "originalaxesticks" = AXESTICKS(
DEFAULT,DEFAULT,_ATTRIBUTE("source" = "mathdefault"))]))



Update

This below is a proc that takes PLOT data struct and returns correct x,y ranges.  It seems to work ok on few tests I did. Bug reports are welcome.

 > restart;
 > #gets a PLOT struct and returns correct x,y ranges get_x_y_range:=proc(p)::list; local T,from_x,to_x,from_y,to_y;    try       T:=plottools:-getdata(p,'rangesonly');    catch:       error StringTools:-FormatMessage( lastexception[2..-1] );    end try;   from_x := op(1,T[1]);   to_x   := op(2,T[1]);   from_y := op(1,T[2]);           to_y   := op(2,T[2]);                  if from_y=to_y then      if from_y<0 then         to_y   := 0;                         from_y := from_y-abs(from_y)/2;      elif from_y>0 then                              from_y := 0;         to_y   := to_y+to_y/2;     else         from_y := -1;         to_y   := 1;                     fi;                fi;   RETURN([from_x..to_x,from_y..to_y]);              end proc:
 > p := plot(6); get_x_y_range(p)

 > p := plot(-3); get_x_y_range(p)

 > p := plot(0); get_x_y_range(p)

 > p := plot(x); get_x_y_range(p)

 > p := plot(sin(x)); get_x_y_range(p)

 > p := plot(exp(x)); get_x_y_range(p)

 >

Update

Warning.  plottools:-getdata(p,'rangesonly') is buggy. I replaced this with

rhs~(indets(p, identical("originalview")=anything))[];

which gives more accurate Y ranges used. Here is example showing that getdata(p,'rangesonly') returns wrong y ranges for a plot compared to how it shows on the screen, So in the function above, better use the second method instead. This whole getdata(p,'rangesonly'); should be looked at by Maplesoft and fix to make it return correct values that agrees with screen view.

 > sol:=1/2/cos(x)*(sin(x)^2+(sin(x)^4+36*cos(x))^(1/2)); p:=plot(sol,x=-3..3);

 > plottools:-getdata(p,'rangesonly'); #WRONG y values compared to the above plot

 > rhs~(indets(p, identical("originalview")=anything))[]; #better result compared to plot (still not exact but better).

 >

## Wrong Latex generated when using _C1 fo...

Maple 2024

This is some serious problem in Latex in Maple 2024.1

I went back to using _C1, _C2 for my own constants of integration.

But I want to get the nice latex for c__1,c__2.

So to do that, my understanding is that I just need to call Maple's dsolve after restart on some random ode in order to set c__1,c__2 for display only and also for latex.

This below seems to confirm this.  But now the latex generated is all wrong and messed up on some places.

My question is: I want to use use _C1,_C2 (i.e. the traditional constants) in my own code I write which generates solution to an ode, but for Latex, I'd like these to come out as c__1,c__2 since they look nicer.

What is the correct way to do this? What Am I doing wrong here? I do not see it.

 > interface(version);

 > #EXAMPLE showing using _C1 for input and latex. All works OK restart;
 > sol:=y(x) = x+_C1/x^2;

 > #correct latex. No problem compiling, but not nice looking _C1 latex(sol)

y \! \left(x \right) = x +\frac{\textit{\_C1}}{x^{2}}

 > #Example showing what happens when making call to dsolve initially restart;
 > dsolve(diff(y(x),x$2)=0); #this call is used to just activate display of nicer constants  > sol:=y(x) = x+_C1/x^2;  > #bad latex, gives error when compiling with texlive latex(sol) y \! \left(x \right) = x +\frac{c}{_} Download latex_problem_maple_2024_july_18_2024.mw And to confirm this is new problem in Maple 2024, I run the same exact worksheet now in Maple 2023.2, and there it works correctly. i.e. Latex generated is correct in both cases. Here is the Maple 2023.2 worksheet, you can see below the difference in Latex.  > interface(version);  > #EXAMPLE showing using _C1 for input and latex. All works OK restart;  > sol:=y(x) = x+_C1/x^2;  > #correct latex. No problem compiling, but not nice looking _C1 latex(sol) y \! \left(x \right) = x +\frac{\textit{\_C1}}{x^{2}}  > #Example showing what happens when making call to dsolve initially restart;  > dsolve(diff(y(x),x$2)=0); #this call is used to just activate display of nicer constants

 > sol:=y(x) = x+_C1/x^2;

 > #good Latex now in Maple 2023.2. latex(sol)

y \! \left(x \right) = x +\frac{c_{1}}{x^{2}}