Carl Love

Carl Love

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13 years, 157 days
Himself
Wayland, Massachusetts, United States
My name was formerly Carl Devore.

MaplePrimes Activity


These are replies submitted by Carl Love

Please show explicitly the code that does not work.

@sarra Remove the range option! That was not in your code when I made my recommendation. Your range is already set at -50..50 by your boundary conditions. Please don't change your original code and then say that my fix doesn't work!

@mahmood180 Please post this as a seperate Question. It seems unrelated to the original.

@c4meleon Change the dsolve command to

res:=dsolve({diff(y(x),x)=f(x,y(x)),y(0)=1}, {y(x)});

You must be using a significantly older version of Maple. Which is it?

@c4meleon Please show your dsolve command that is not working.

@Preben Alsholm There have been several versions of this problem posted by the OP in recent weeks, with various amounts of specificity as to what the symbols mean. The suggestion that A is a linear operator with spectral radius less than 1 was put forth by me. However, looking at the other versions of this problem, it is clear that A is not a linear operator. In one version, A is given by a procedure. The f's are NxN matrices, and A operates on some elements of interior of f, replacing them with the average of the four horizontally and vertically adjacent elements.

@Preben Alsholm My square brackets after D were unintentional. I'm also surprised that they worked. Thanks for spotting that. I'll fix the original.

@Axel Vogt Continuity of the integrand is obvious over a nonnegative interval. But Maple refuses to do the definite integral even when specific nonnegative limits of integration are supplied. Here's a simplified example:

Maple does the indefinite integral:

int(t^(5/2)*exp(t^(5/2)), t);

Maple does not do the definite integral:

int(t^(5/2)*exp(t^(5/2)), t= 0..1);

@dohashi I agree with itsme that Grid:-Map should just go ahead and copy the full memory state of the main kernel.

Regarding that fourth paragraph of ?Grid,Map : Could you show an example where Map is not "called outside the grid, on a non-compute node, not as part of a parallel computation"? I.e., an example where it is called as it "is designed to be called on all the nodes of a parallel computation." Would the last example at ?Grid,Map , where Launch is used, be an example of what the fourth paragraph refers to as "robust" use?

@itsme: Does your wrapped and Mapped procedure use global variables? I wonder if that is the issue. If it is, then maybe you could put the procedure in a module.

@mehdi jafari Numeric solution of PDEs without a time component is not currently implemented.

@Edinburgh Please explain what you are trying to plot. Is it simply the bezier curve with control points P[0]...P[5]? Why are you using complex numbers?

@Ahm3d Are you sure that the range of the integrals is supposed to be n..(n+1)*h? That seems strange to me. Are you sure that it is not n*h..(n+1)*h?

@Ahm3d Sorry about that. I had eval(F, n*h). That was supposed to be eval(F, t= n*h). I corrected the Answer. Please try again.

Since there is no actual error in the integration after you do the restart, what you say about the numerator is irrelevant.

You might be better off using a procedure-based numerical integration for the Optimization. I'll try it both ways in a few hours. Can I assume that is positive integer and h is positive?

I think that everyone is having that problem as a result of the MaplePrimes upgrade on Wednesday April 16.

@geischtli The main tool to use is plottools:-scale. This operates on a frame after it has been created by plot3d. In the code below, I take the fourth and final frame from your animation, l(4), and put it on the same scale (same axes) as the first frame. Then I display these in a simple two-frame animation:

x1:= -2..1:              y1:= -1.5..1.5:     #first frame axes
x4:= -0.82..-0.7:   y4:= -0.2..-0.08: #last frame axes
L(4):= plottools:-scale(
     l(4), #first frame from your code
     (op(2,x1)-op(1,x1))/(op(2,x4)-op(1,x4)), #scale factor for x
     (op(2,y1)-op(1,y1))/(op(2,y4)-op(1,y4)), #scale factor for y
     1, #don't change z
     [(op(1,x4)+op(2,x4))/2, (op(1,y4)+op(2,y4))/2, 0] #central point of last frame
):

plots:-display([l(1), L(4)], insequence = true);

Unfortunately, the tickmarks are the same on each frame. I don't think that this can be changed. The ordinary tickmarks option will not correct this: The tickmarks of the last frame are applied to all frames once it's animated.

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