denitsastaicova

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12 years, 217 days

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These are questions asked by denitsastaicova

In short, I want to create a density plot but with points. So I do a pointplot and I want to color it according to the value of a third function. 

So let's say I do:

>x1:=[seq(x,x=1..2,0.02)];

>y1:=[seq(y^3,y=1..2,0.02)];

>z1:=[seq(x1[i]/y1[i],i=1..51)];

And I want a plot like:

>pointplot([x1,y1])

but with a color corresponding to the gradient of z1.

What I can do is something like:

>pointplot([x1,y1], colorscheme=["valuesplit", z1, [0..0.5="Black",0.5..1="RoyalBlue"]])

but that's not as pretty as it could be. So is there a way to do something like colorscheme=["zgradient", z1]? This doesn't work because zgradient expects its first argument to be colors and then you can add markers, but they apply to the function you plot, not to a third function.

Any ideas?

colorscheme=["zgradient",["Orange","Red","NavyBlue"]]

I have this very ugly ODE system which I solve with "dsolve, numeric, complex=true". It works ok but I'd really like to be able to use events. The problem is that the solution of the system has very small (~10^(-Digits)) imaginary part and as we know "events" works only for real ODEs.

My question is does anyone know a way to force dsolve to solve the ODE as a real system? In Mathematica, there is the function "chop" which does the trick. In Maple, I tried with fnormal and also by forcing some terms to be real but that makes it hit a singularity at 0.01 which doesn't exist when it integrates it as a complex system. In Mathematica, it integrates ok with "chop" without any random singularities. 

I'm currently trying separating the system into real and imaginary parts, but considering how ugly the system is, it may not be so simple (and so far, it doesn't work). So something to trick dsolve would come handy.

Thanks in advance.

Hi all.

Ok, I'm trying to save to a file a set of a complex number, a float number and an integer. According to Maple Help this can be done with:

writedata[append]('terminal',[-0.123456-0.123456*I, 0.1334423423*10^(-15),3], float, proc(f,x) fprintf(f,`%a`,x) end proc);

And it works (the numbers are just an example of what I'm trying to do).

The problem is that I want to change the precision of the second number (or to all of them) to say 5 digits. But when I try as the help suggests:

Hi, I'm trying for some time to create an adaptive procedure which modify the interval of the argument of a function depending on its values. The problem is that I still can't make the "if statement" to work the way I want it. The problem is that the cycle initiate some step "p" in the beginning and it use it trough the cycle although the value of the variable "p" already is different than the initial one. After printing it out, the interval changes with the initial value and the value of p changes independently. Which implies that Maple stores the initial value somewhere and use it from there, not from the immediate memory.
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