Blog

Sometimes, when I use ParallelEvaluate to define some functions on each parallel kernel, which use kernel specific constants, e.g.: ParallelEvaluate[ a=10; fun[x_]:=x^a; ] I would like to have the same function fun[x] defined on the controlling process as well as the subordinated kernels. So far, I just trivially copy-paste the same code and execute itRead more

I used to think it is the miner who verify the transaction, but it turns out this is really a joint work by the miner and the full nodes; the miner broadcasts the newly discovered block, which contains transactions to the network of full nodes, but it is up to the full node to decideRead more

A slightly less general version of this question was asked, in a subsequent comment, by the OP of the question at Controlling subsolutions of a second order linear ODE Let $ f:[0,\infty) \to \mathbb{R}$ obey the differential inequality \begin{equation} f” – 2a f’ + (a^2+b^2) f \le 0,\tag{*} \end{equation} where $ a\in\mathbb R$ and $Read more

Is it possible to control the width of FormFunction? Related, is it possible to have more than 4 inputs in a row in FormFunction? Two code examples. Example 1 produced a row of 4 inputs. cd[E4] = CloudDeploy[ FormFunction[ FormObject[ “DTS” -> CompoundElement[<| “Year” -> Range[2010, 2018], “Month” -> Range[1, 12], “Day” -> Range[1, 30],Read more

I want to control the thickness of the line in ParametricPlot3D. I read the answer in Thickness definition for ParametricPlot3D but it does not solve the problem. In the example below, thickness = 3.0;ParametricPlot3D[{Sin[u], Cos[u], u/10}, {u, 0, 20}, PlotStyle -> AbsoluteThickness[thickness]] the thickness changes abruptly from something very thin (for my taste) to somethingRead more

Let $ f:[0,\infty) \to \mathbb{R}$ obey the differential inequality $ $ f” – 2\alpha f’ + 2\alpha f \leq 0$ $ where $ 0 < \alpha < 2$ is some constant. If $ f(0) = 0$ and $ f'(0) = 1$ , can I say that $ f(x) < e^x – 1$ for some $Read more

I’m looking to develop some Android applications to use as prototypes. The apps need to be kept in sync with some video footage (by this, I mean if the video shows the number 3, the apps all update to show the number 3 at the same time etc.) I need to be able to doRead more

Consider a large $ n\times n$ symmetric matrix $ A$ . How large should $ k$ be for a random $ k\times k$ symmetric submatrix $ B$ to satisfy: $ $ \frac{1}{k} \|B\|_2 \leq \frac{2}{n}\|A\|_2$ $ with high probability? In the situation I am considering, the distribution of the columns of $ A$ , dividedRead more