PatrickT

Dr. Patrick T

2028 Reputation

18 Badges

11 years, 275 days

MaplePrimes Activity


These are replies submitted by PatrickT

@Alejandro

I just tested the "edit" function, and it's true: if you edit and "submit" nothing happens, but if you go back to the previous url and refresh the edit has actually been registered! Wonderful!

@Alejandro Jakubi 

Hola Alejandro,

it's only distressing if you think about it!

;-)

 

 

P.S. I admire your archiving system. Half of the time when I search for a question, I am led to a question I wrote myself, with perfectly decent answers: it's very important to be able to go into the archives. I can rarely find what I'm looking for via mapleprimes, but if I google "mapleprimes+stuff" it usually works... [unless it has been deleted of course]

@PatrickT 

I still think mapleprimes is the number one online Maple community. But I also don't get the insistance on staying with a technology that has multiple bugs and breaks so easily when one could simply move to http://mapleprimes.stackexchange.com/ or something like that. I understand keeping it "inside" for the beta side of things, but wouldn't it be easier simply to adopt a successful model, together with its points and badge system and all the rest? What is in there for Maplesoft/Mapleprimes that they so badly want to add to their already busy agenda?

P.S. Not sure if it's a bug, a browser problem or my being particularly thick today, but I just made 3 attempts to edit "I took have scaled down" to "I too have scaled down" and it's not registering with mapleprimes: I press submit, the page refreshes, but takes me back to the edit mode. So I'll leave like that for now.

@Markiyan Hirnyk 

If you really want to know, pick handles with over 1000 points and "trace" them to stackoverflow, say, and you will see. I have noticed at least 3 very active members of mapleprimes move. I too have scaled down my participation.

@Kitonum 

you have an unwanted bracket.

your output is:

           Vector[column](%id = 18446744078078130286)
                         Vector[column]

but this is what it looks like from my end -- we've talked about this before ;-)

 

Assuming the image below is correctly inserted (I can see it in preview mode but not in normal browsing mode, a bug I remember from several years ago):

 

 

 

@J4James 

could you post your full worksheet?

and which version of Maple are you using?

@Carl Love 

Great thanks Carl!

@Carl Love 

Great thanks Carl!

I get an empty plot with the following error message:

Warning, expecting only range variables [x, y] in expression `if`(59 < x/y,undefined,expr) to be plotted but found name expr

The range for expr is 1..10 instead of -200..500. Copied your code verbatim.


I'm using Maple 17.01 on Windows 64bits (not yet applied 17.02)...

I get an empty plot with the following error message:

Warning, expecting only range variables [x, y] in expression `if`(59 < x/y,undefined,expr) to be plotted but found name expr

The range for expr is 1..10 instead of -200..500. Copied your code verbatim.


I'm using Maple 17.01 on Windows 64bits (not yet applied 17.02)...

Just recently I was confronted with a situation where I wanted to draw a sequence of plots with a "division by zero" asymptote. Using the 'discont' option proved impractical, because the computations were intensive.

There may have been (almost surely) a better workaround than what I did below, but let me describe what I did, for the record: I created plots that I "manually" truncated before the asymptote and then redisplayed together. The way I did it, unfortunately, the plot colors were the same for all the individual plots, so I used a workaround consisting in recoloring the plots. Tedious, but it worked. If there was an easier way, of course, it would be good to know.

restart;
f := (x,y) ->1+1/(y-1/x);

xMin := 0:
xMax := 1:
fMin := -50:
fMax := +2:

plot(f(x,1.1),x=0..xMax);
# curves to draw
yList := [1.01, 1.015, 1.02, 1.025, 1.03, 1.035]:
iMax := numelems(yList):

# critical points
# solve({1/(f(x,y)-1)=0,x>0},x);

# critical values for different values of y in yList
xAsymptote := [seq(rhs(op(solve({1/(f(x,y)-1)=0,x>0},x))), y = yList)]:

# Map y to critical values
xAsymptoteMap := y -> xAsymptote[ListTools:-Search(y,yList)]:

# Check critical values
[seq(xAsymptoteMap(y), y = yList)];
# plot a list -> colors change
# plot( [seq(f(x,y),y=yList)], x = xMin .. xMax);

# use 'discont' option to remove asymptotes
plot( [seq(f(x,y),y=yList)], x = xMin .. xMax, 'discont'):
plots:-display(%, 'view' = [ xMin .. xMax, fMin .. fMax ]);

# display a list of plots -> colors all the same
# wrong approach in general, unless the 'discont' option consumes too many resources

# seq([plot(f(x,y), x = xMin .. xMax)],y=yList):
# plots:-display(%);

seq([plot(f(x,y), x = xMin .. xMax, 'discont')],y=yList):
plots:-display(%);

# create a list of plots with default settings
plot_list := [seq( plot(f(x,y), x = xMin .. xMax), y = yList )]:
plots:-display(%, view = [xMin .. xMax, fMin .. fMax]);

# create a list of plots cut off before the asymptote
plot_list := [seq( plot(f(x,y), x = xMin .. 0.99*xAsymptoteMap(y)), y = yList )]:
plots:-display(%, view = [xMin .. xMax, fMin .. fMax]);
# above procedure generates the plots separately and displays them sequentially
# to obtain different colors, each plot's color must be reset
# there seems to be no easy way to otherwise deal with the asymptotes
# create list of colors (here using Maple default)
colorlist := plots:-setcolors(default): # obtain the default list of colors
# procedure to recolor each plot
recolor := proc(p, color) # takes Hex values as input
subsindets(p
, 'specfunc(anything, {COLOR, COLOUR})'
, clr -> COLOUR(RGB,op(ColorTools:-HexToRGB24(color))/255.0) # convert Hex values to RGB values
)
end proc:

xyPlot := plots:-display(
recolor~(plot_list, colorlist[1..iMax])
, 'tickmarks' = [5, 5]
, 'labels' = [ 'x', 'y' ]
, view = [ xMin .. xMax, fMin .. fMax ]
) : xyPlot ;



With the simple function above, there are no problems with the 'discont' option. However, if one replaces f with the following, the computations for the 'discont' option seemed to go on forever, and hence the tedious workaround I used.

f := (x,y) -> 1+1.04/((1.04*(1-.9805806757*sqrt(x)))*sqrt(3006.731693*y^2/x-3124)+1.000320102*y-1.04);

xMin := 0:
xMax := 1.1:
fMin := 0:
fMax := +10:

Just recently I was confronted with a situation where I wanted to draw a sequence of plots with a "division by zero" asymptote. Using the 'discont' option proved impractical, because the computations were intensive.

There may have been (almost surely) a better workaround than what I did below, but let me describe what I did, for the record: I created plots that I "manually" truncated before the asymptote and then redisplayed together. The way I did it, unfortunately, the plot colors were the same for all the individual plots, so I used a workaround consisting in recoloring the plots. Tedious, but it worked. If there was an easier way, of course, it would be good to know.

restart;
f := (x,y) ->1+1/(y-1/x);

xMin := 0:
xMax := 1:
fMin := -50:
fMax := +2:

plot(f(x,1.1),x=0..xMax);
# curves to draw
yList := [1.01, 1.015, 1.02, 1.025, 1.03, 1.035]:
iMax := numelems(yList):

# critical points
# solve({1/(f(x,y)-1)=0,x>0},x);

# critical values for different values of y in yList
xAsymptote := [seq(rhs(op(solve({1/(f(x,y)-1)=0,x>0},x))), y = yList)]:

# Map y to critical values
xAsymptoteMap := y -> xAsymptote[ListTools:-Search(y,yList)]:

# Check critical values
[seq(xAsymptoteMap(y), y = yList)];
# plot a list -> colors change
# plot( [seq(f(x,y),y=yList)], x = xMin .. xMax);

# use 'discont' option to remove asymptotes
plot( [seq(f(x,y),y=yList)], x = xMin .. xMax, 'discont'):
plots:-display(%, 'view' = [ xMin .. xMax, fMin .. fMax ]);

# display a list of plots -> colors all the same
# wrong approach in general, unless the 'discont' option consumes too many resources

# seq([plot(f(x,y), x = xMin .. xMax)],y=yList):
# plots:-display(%);

seq([plot(f(x,y), x = xMin .. xMax, 'discont')],y=yList):
plots:-display(%);

# create a list of plots with default settings
plot_list := [seq( plot(f(x,y), x = xMin .. xMax), y = yList )]:
plots:-display(%, view = [xMin .. xMax, fMin .. fMax]);

# create a list of plots cut off before the asymptote
plot_list := [seq( plot(f(x,y), x = xMin .. 0.99*xAsymptoteMap(y)), y = yList )]:
plots:-display(%, view = [xMin .. xMax, fMin .. fMax]);
# above procedure generates the plots separately and displays them sequentially
# to obtain different colors, each plot's color must be reset
# there seems to be no easy way to otherwise deal with the asymptotes
# create list of colors (here using Maple default)
colorlist := plots:-setcolors(default): # obtain the default list of colors
# procedure to recolor each plot
recolor := proc(p, color) # takes Hex values as input
subsindets(p
, 'specfunc(anything, {COLOR, COLOUR})'
, clr -> COLOUR(RGB,op(ColorTools:-HexToRGB24(color))/255.0) # convert Hex values to RGB values
)
end proc:

xyPlot := plots:-display(
recolor~(plot_list, colorlist[1..iMax])
, 'tickmarks' = [5, 5]
, 'labels' = [ 'x', 'y' ]
, view = [ xMin .. xMax, fMin .. fMax ]
) : xyPlot ;



With the simple function above, there are no problems with the 'discont' option. However, if one replaces f with the following, the computations for the 'discont' option seemed to go on forever, and hence the tedious workaround I used.

f := (x,y) -> 1+1.04/((1.04*(1-.9805806757*sqrt(x)))*sqrt(3006.731693*y^2/x-3124)+1.000320102*y-1.04);

xMin := 0:
xMax := 1.1:
fMin := 0:
fMax := +10:

I do not mind other languages, I suggest people just ignore posts in languages they do not understand. Soon you'll be begging to use English when everyone else is using Chinese...

I started using Maple in 1995. My university at the time had every software in the world and I played with Matlab, Mathematica, Maple, and so on. I needed to solve differential equations, both symbolic and numerical, and plot trajectories, so I quickly discarded Matlab as I disliked going back and forth between software. I mainly relied on adapting existing code I found on the internet, which at the time was not a lot. I remember distinctly finding Maple more intuitive, but that may have been because I had a better sample code at hand. As with Alejandro, one of the main criteria for my choice was speed: at the time, running Mathematica and Maple on the university servers was very slow, so I got local copies installed on my destktop by the IT people (I remember something about their having only 15 or so licenses available but it was okay because only 2 had been claimed so far). Maple was by far the quickest so I relied on it for most of my computations. Whenever the Standard GUI became available I stayed on the classic GUI for years. As Alejandro says, Maple became more of a hog with the introduction of the Standard interface. To this day, I curse every time I launch the Standard GUI, despite my 7 cores and all that. 

I was nearly made to switch to Mathematica when I changed universities, but I managed to get our department to buy several licenses because at the time Maple came bundled with Matlab and people thought that was a guarantee. When Maple became unbundled, the department stopped buying licenses, but I soon moved to another place. I eventually switched to Standard GUI because of problems producing graphs with the Classic GUI. I have now switched a lot of my computations to R because of frustration with plot quality (this has improved somewhat since Maple 16) and also because I could not get my Mathematica-using co-authors to use Maple: R was easier to "sell" on the grounds that it was freeware. I still use Maple for symbolic manipulations. Always in Worksheet mode and 1-D input. Whenever possible with the Classic GUI. I have toyed with freeware CAS but I still mainly use Maple because it is costly to learn new ways: I have sample code written over the years which I adapt from one application to the next.

But the number one reason I have stayed with Maple is mapleprimes (and the Maple community at other sites like stackoverflow), knowing that if get stuck I'll get a hint or a fully worked out answer within a few hours. For the same reason my switch to R was made easy.

My thoughts, based on a very partial view of course, is that Maple has tried to do too much and has at times forgotten to focus on their core activity: to have 1D and 2D, to have worksheets and documents, to have Classic GUI and Standard GUI, and at the same time not to be able for many years to produce publishable graphs, to me that's a big mistake...

@wingjammer 

Oh I misread your questions. I don't think there's a simple way, none that is documented.

You could produce a postscript and then alter it with procedure, but that would be tedious.

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