Carl Love

Carl Love

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12 years, 332 days
Himself
Wayland, Massachusetts, United States
My name was formerly Carl Devore.

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These are replies submitted by Carl Love

@goli A better way to correct the second plot is to get better spacing of the points by using logarithmic scaling on the parameter:

plot([eval(ns, t= 10^t), eval(r, t= 10^t), t= 11..17], 0.8..1.2, 0..1);

@goli A better way to correct the second plot is to get better spacing of the points by using logarithmic scaling on the parameter:

plot([eval(ns, t= 10^t), eval(r, t= 10^t), t= 11..17], 0.8..1.2, 0..1);

@goli By redisplaying the plots with style= point, you can see that in the second plot, the points are all bunched up at the bottom. If you redo the second plot with numpoints= 21000, then it will look like the first plot.

You are almost right that all the points are inside the view. In each plot, there is one point outside the view.

 

 

restart:

A:=4*(10)^(-28):

lambda:=20:

p:=ln(t)^(-lambda)/(A*lambda)*(ln(t)-lambda+1):

a:=3*(A*lambda/t)^2*ln(t)^(2*(lambda-1)):

b:=diff(a,t):

c:=diff(b,t):

d:=(-c/b):

e:=b/a:

h:=A*lambda/t*ln(t)^(lambda-1):

i:=diff(h,t):

j:=i/h:

x:=(1/(2*h))*(d+j+e):

ns:=1+2*x-2*p:

#plot(1+2*x-2*p):

k:=diff(x,t):

l:=diff(p,t):

nrun:=2/h*(k-l):

r := 16*p:

P1:= plot([ns, r, t = 10^11..10^15], 0.8..1.2, 0..1):

A:= op([1,1],P1);

Vector(4, {(1) = ` 210 x 2 `*Matrix, (2) = `Data Type: `*float[8], (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

P2:= plot([ns, r, t = 10^11..10^17], 0.8..1.2, 0..1):

B:= op([1,1],P2);

Vector(4, {(1) = ` 210 x 2 `*Matrix, (2) = `Data Type: `*float[8], (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

plots:-display(P1, style= point);

plots:-display(P2, style= point);

 

NULL

 

Download_13.3.mw

@goli By redisplaying the plots with style= point, you can see that in the second plot, the points are all bunched up at the bottom. If you redo the second plot with numpoints= 21000, then it will look like the first plot.

You are almost right that all the points are inside the view. In each plot, there is one point outside the view.

 

restart:

A:=4*(10)^(-28):

lambda:=20:

p:=ln(t)^(-lambda)/(A*lambda)*(ln(t)-lambda+1):

a:=3*(A*lambda/t)^2*ln(t)^(2*(lambda-1)):

b:=diff(a,t):

c:=diff(b,t):

d:=(-c/b):

e:=b/a:

h:=A*lambda/t*ln(t)^(lambda-1):

i:=diff(h,t):

j:=i/h:

x:=(1/(2*h))*(d+j+e):

ns:=1+2*x-2*p:

#plot(1+2*x-2*p):

k:=diff(x,t):

l:=diff(p,t):

nrun:=2/h*(k-l):

r := 16*p:

P1:= plot([ns, r, t = 10^11..10^15], 0.8..1.2, 0..1):

A:= op([1,1],P1);

A := Vector(4, {(1) = ` 210 x 2 `*Matrix, (2) = `Data Type: `*float[8], (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

P2:= plot([ns, r, t = 10^11..10^17], 0.8..1.2, 0..1):

B:= op([1,1],P2);

B := Vector(4, {(1) = ` 210 x 2 `*Matrix, (2) = `Data Type: `*float[8], (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

plots:-display(P1, style= point);

plots:-display(P2, style= point);

 

NULL

 

Download 13.3.mw

Where did you get the package posets? It is not in the standard Maple library.

@mathdude023 I was hoping that the general form would remind you of arctan(x), whose derivative is 1/(x^2+1). That's pretty close to 1/(2*x^2+5). Try factoring out 5 from the denominator---equivalent to factoring out 1/5 from the whole integral.

@mathdude023 I was hoping that the general form would remind you of arctan(x), whose derivative is 1/(x^2+1). That's pretty close to 1/(2*x^2+5). Try factoring out 5 from the denominator---equivalent to factoring out 1/5 from the whole integral.

The debug thing is weird, but before you applied debug, everything seemed normal and as expected to me. The procedures followed the documented rules as far as I know them.

Nonetheless, thanks for pointing out / discovering a very interesting property of debug.

The debug thing is weird, but before you applied debug, everything seemed normal and as expected to me. The procedures followed the documented rules as far as I know them.

Nonetheless, thanks for pointing out / discovering a very interesting property of debug.

@jaytreiman ShowSolution won't do anything with this problem.

Coach: Start by letting u = x^6/6 because then du = x^5 dx. After you do that step, ShowSolution can do the rest.

@roman_pearce I wasn't saying that the grid size was the cause of the inordinately long time. I was suggesting that the bugs be worked out first on a smaller grid before trying for the 200x200, which may be small in the world of contour plots, but is still 64 times larger than the Maple default contourplot.

We must also consider the possibility that the function being evaluated is getting hung up on a particular grid point, or on a small subset of the points.

A slight improvement can be made by including the vertical range in the plot so that it matches the one in the implicitplot:

Q:= plot(f, x= -10..10, y= -10..10, discont);

 

A slight improvement can be made by including the vertical range in the plot so that it matches the one in the implicitplot:

Q:= plot(f, x= -10..10, y= -10..10, discont);

 

200 x 200 is quite a large grid. Have you tried on a smaller grid? How about posting the function that you're trying to plot?

@Markiyan Hirnyk Agreed. This is definitely a frequently asked question (FAQ).

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