Carl Love

Carl Love

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12 years, 123 days
Himself
Wayland, Massachusetts, United States
My name was formerly Carl Devore.

MaplePrimes Activity


These are replies submitted by Carl Love

If the function x(t) is not known, then how will you use B?

What is the datatype of the entries that are supposed to be floats? Are they strings? If you're not sure, extract one entry from the Vector, for example x:= V[1], and check its op(0,x) to find out. Also helpful is lprint(x).

@maple fan Unfortunately, just because a Maple property exists, it doesn't necessarily mean that any other commands use that property. Since there seems to be no other help page with MutallyExclusive, that's a clue that it is not used. However, it's possible that it is used somewhere. You can do the following with any property:

assume(a::MutuallyExclusive);

is(a::MutuallyExclusive);

                   true

A great many commands, maybe the majority, make no use at all of assumptions.

@fereydoon_shekofte 

So, you need to find a particular value in an RGB image, and it may occur several times. Approximately what size images are we talking about? 500 x 500? About how many times do you expect to find it (very roughly, order of magnitude)? Can the value be in any of the three color layers? Is the special value 1?

After you've found the indices that point to the particular value, you want to pair those indices with another list of values. Where does that second list of values come from?

And then you want to create a Matrix using those index-value pairs. What do you plan to do with that Matrix?

 

I am curious what Windows Task Manager says during those 40 seconds. Is the Disk Utilization or Network Utilization maxed?

I wonder what are the steps that led to the set of indices and the set of values. And I wonder what you plan on doing with the resulting set of equations. I suspect that you could be about to attempt something terribly inefficient that could be better handled with Matrices.

@OffshoreEngineer I assume from your dependent variable names that you are using cylindrical coordinates. How about trying to solve the BVP in Cartesian coordinates?

@OffshoreEngineer For what it's worth, I tried two other things, with no substantial change in the results. The first was to reduce each coefficient to a single significant digit. The second was to divide through each equation by its leading coefficient. So, I don't think that the phenomenon under discussion in this thread is a numerical/computational issue.

@OffshoreEngineer For what it's worth, I tried two other things, with no substantial change in the results. The first was to reduce each coefficient to a single significant digit. The second was to divide through each equation by its leading coefficient. So, I don't think that the phenomenon under discussion in this thread is a numerical/computational issue.

@emma hassan I hope that you caught the small mistake in my Answer, which I've since corrected. I had

S:= LinearSolve(A, XY);

which should have been

Solution:= LinearSolve(A, XY);

@emma hassan I hope that you caught the small mistake in my Answer, which I've since corrected. I had

S:= LinearSolve(A, XY);

which should have been

Solution:= LinearSolve(A, XY);

What is mdcs? I guess it's a debugger.

What is mdcs? I guess it's a debugger.

I got somewhat different results. In Maple 17 Standard (Windows8, 64bit), I had no trouble: The help pages open and look great. In Maple 16.02 Standard (Windows8, 64bit), I get "No matches found" for both ?Janet and help(Janet), even though the package commands themselves are loaded.

I don't have Matlab to test this, but what if you take out the quotes? Make it

maple(fsolve(a*x^2-4))

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