Computer Science questions and answers

I see that there are many files in the ScaLAPACK library without any immediately obvious naming convention... I'm sure that if the first letter is "p", it means parallel. But I'm not sure how to make sense of the rest of the names as seen here (http://www.netlib.org/scalapack/explore-html/dir_78dd70a4654792622dd59c7dbd6a0c9f.html). ....

I am trying to write a program to compute the advection equation. $$u_t +u_x = 0$$ I use the spectral method for the spatial derivative $u_x$ and the leapfrog method for the time derivative $u_t$. That will give the an equation for the next time step: $$u_{j}^{k+1} = u_{j}^{k-1} - ....

When gmsh uses higher-order tetrahedral elements, there is an underlying Lagrange basis used to specify the map from reference space to the element. I'm trying to load a gmsh mesh of 3rd degree tetrahedral elements, but I can't seem to find any precise documentation on the location of the nodes ....

For an stationary iteration method solving $Ax=b$ as follows: $$ Mx_k = Nx_{k-1}+b, $$ I have known that when $M = I$, i.e., the Richardson iteration, the k-th solution $x_k = x_{k-1}+r_{k-1}$ is in the k-th Krylov subspace $K_k(A,b)$ with $x_0=0$. So, if we use a Krylov subspace method e.g., ....

I'm asking about the solution of the Helmholtz equation on a periodic domain with piecewise constant wavespeed in different frequency regimes. One possible approach is to solving this problem is to write down integral equations on the boundary surfaces in terms of the Green's function of the system. Since the ....

Is there a complexity degree that is bigger than $O(n)$ and smaller than $O(n \log n)$? ....

I have a set of points $(x_i,y_i,u(x_i,y_i))\in\mathbb{R}^3$, $i=1,\dots N$, over a surface $S$ (from experimental data). I need to calculate the integral of a function $F$ over that surface. If the points were points over a volume I could use some mesh software (tetgen, for example) and build a mesh, ....

I have just installed a Nvidia GT660 graphic card on my desktop and, after some struggle, I manage to interface it with R. I have been playing with several R packages that use GPUs, especially gputools, and I was comparing the time taken by my GPU and CPU to perform ....

I have a function: delt=1 #trial def f(z): return ((1-2*z)*np.exp(-delt/z))/(((1-z)**(2+delt))*(z**(2-delt))) I also have a variable: import scipy.integrate as integrate var=integrate.quad(f,0,0.5) # equals 0.040353419593637516 Now I am trying to find the value p such that integrate.quad(f,0.5,p)= var and manually I can check that it is around 0.605 I define the following ....

So I'm trying to implement a Gauss-Kronrod adaptive quadrature. That is, I want to calculate $$\int_a^b f(x) dx = \sum_i f(x_i) w_i$$ where f(x) is evaluated at multiple points at once for efficiency. A key point to bear in mind is that $f$ is also vector-valued (possible risk of confusion ....