yeah.it1s funny.a few collegues in applied hate it.actually they don'nt know much about it...shame...anyway.I think people think I'm tooo applied for pure and too pure for applied.I just love math too much.
Is there some kind of sausage that blends some kind of cheese with meat? In Brazil we have a kind of cheese that has almost the same shape of a sausage, I guess this could exist.
: For the food sometimes called a Wiener (sausage), see hot dog or Vienna sausage.
In the mathematical field of probability, the Wiener sausage is a neighborhood of the trace of a Brownian motion up to a time t, given by taking all points within a fixed distance of Brownian motion. It can be visualized as a sausage of fixed radius whose centerline is Brownian motion. The Wiener sausage was named after Norbert Wiener by because of its relation to the Wiener process; the name is also a pun on Vienna sausage, as "Wiener" means "Viennese" in German.
The Wiener sausage is one of the simp...
Am I not allowed to declare functions using #define variables? Like this: #define N 8 /* Number of masses */ #define NEQ 2*N /* Number of equations */ .... static void PrintIntro(int npes, int N, int NOUT);
@Jeff Yes, you can define even complex functions using such macros. For a long time, mathematical functions were defined in the same way to save on performance. But, nowadays, compilers have become much much better and hence, it does not make any sense to define stuff as such, especially if performance is the only factor.
You have to give a type and a dummy variable, if it is only declaration, not definition, there is no need to specify the variable itself except for readability purposes.
this is a rather advanced program for a C newbie. It uses MPI (do you know what that is?) and an advanced math library called CVODE, which is an ODE solver.
what! no way! I was beginning to think nobody had similar experience. I'm working alone and have had sooo much difficulty getting answers to questions. My prof. is a math professor and doesn't know computers. He selected me for this project because I have some programming experience - but not in this.
Yes, stackoverflow does, but there was nobody there right now. And also they are not nearly as friendly as here in math.
My prof wants me to program the FPU system. Then he wants me to do it in 2 dimensions - all so that I can get my master's degree! (in his defense, it is my master's thesis)
no. i'm a year behind. i already finished my classwork.
my professor is very intimidating (though he doesn't know it) and i had m hands full just trying to pass classes, so I didn't do much work at all on this until the last few months.
yes. i found that out when i tried to install gentoo linux on a spare machine i had at home so i could learn on it!
i spent months trying to figure out how to install it and then install CVODE and, after all that, found out that since I'm using MPI, I can't do anything on my home system anyway! :D
my friend doing the FEM work? she is using some Windows based tool to do her FEM work. i offered to help her, because she is not computer savvy. But she continued on her own.
@Jeff oh, so she must be using some commercial software (Ansys or similar) Anyway, my point is, MPI is tricky, so most of the libraries provide option to run methods without MPI.
You know how you have to split a 2nd order ode up into two first order equations? And you know how you have to split the problem up into the number of processors it's going to run on?
in other words, if you have 20 equations and 4 processors, you have 5 equations on each processor. then each process has to send the left most number to the previous processor and the right most number to the next processor. understand what i mean?
The function below that, called "f", is the RHS of the example code. About 20 lines into that function is the comment /* Pass needed data to processe...
That, and the next paragraph, are sending the results of each equation to the process to the left and the right
well, that works easily for a first order ODE. i have a second order one. so i'm trying to think of strategies for how to organize the system and what info to send to whom.
A better way to deal with the stuff is to separate the association of masses from processor and instead, deal with the equations as associated with the processor.
So now you will have two levels of equations.
The first set is that of for the masses and the second is for the derivatives.
And now, apply similar strategies to each of them .Send a value to the previous and send a value to the next.
First solve the equation for the for masses, then for derivatives or reverse.
are you saying to put the first step of the equations on one set of processors, then the second set on another set of processors? i think that would be way too much communication, no?
@jay to clarify: if my system is $\ddot{u}_n=u_n$, I introduce variable $v_n$ and break it up into the first equation $\dot{u}_n=v_n$ and the second equation $\dot{v}_n=u_n$.
No, I was going to comment on that statement. I was saying, treat them independently. Like suppose you have 1000 "first equatiosn" and 990 something "Second equations"
@jay i really think that would be a lot of communication, because the second equations depend on the firsts. i was thinking of grouping the equations so that if i have 1000 masses (that's 2000 equations), then if a processor handles 50 masses, it does two levels (100 equations) of processing, and pass the results right and left.
the reason i suggested the other alternative is you are then just basically solving a first order equation thrice. The code complexity reduces and the bugs too. You can reuse the first order code for any order you want.
so we don't have to worry about different data structures.
@Will the basic answer is that it's sucking humidity out of the air. But good ACs don't leak. A good AC should be able to evaporate the water right back into the air, but on the outside.
But the guy was like: well... maybe we need to test again like punctions or whatever. I am like hell now what wait what? No. Fix this first please. Hmm.
Perhaps a bit like (but totally not like!) a friend of mine that had some extra metastasis and was like "what does it matter a few more tumors? Have plenty of them already" with a really big smile.