Eric Brown
Reputation
2,432
Next privilege 2,500 Rep.
Create tag synonyms
 Mar 3 comment Replacing Excel with Mathematica Using 2D Tables I think you would need Mathematica's Dynamic functionality, from which you could hack up some reactive programming which makes Excel so popular. Feb 22 comment Slow JoinAcross performance 3.0 seconds v10.2/Mac. I guess we've bracketed it to a change between 10.2 and 10.3. Thanks everyone, I have contacted Wolfram Support. Nov 26 comment Adding two random variables (probability distributions) I think you want TransformedDistribution. Nov 23 comment Mathematica, MKL_NUM_THREADS, and GNU/Linux Process Limits @ilian i think this may be the solution, thanks! i'm going to test this for a bit and then write back. Nov 16 comment How does Matematica compute the CDF of the binomial distribution? For what it is worth, Mathematica usually prefers slow and accurate over fast and approximate. Nov 16 comment Can symbols like + or * be used to denote the Plus and Times functions? @Szabolcs That's what it is! Thanks. I was confused because I had Notation working for * then not. Nov 15 comment Can symbols like + or * be used to denote the Plus and Times functions? It's more terse functional style. Nov 15 comment Can symbols like + or * be used to denote the Plus and Times functions? Its more functional style. Nov 9 comment precision and speed inefficiency issues of Nearest function with sqrt expression What is the question? Nov 9 comment Infinity::indet: Indeterminate expression 0. ComplexInfinity encountered Please format your code, using multiple lines and four spaces before each line of code. Nov 9 comment Solving matrix PDE with a range of free parameters You're welcome, this was fun. I've made a few changes to my answer since I had the arguments to the ParametricFunction reversed. Nov 8 comment Update or Animate an ArrayPlot or MatrixPlot? @Veena right, this is why i chose that particular x Cos[x] function, so that there were no jumps in the function. I'm not sure what you can do if your data don't line up, and you require a smooth transition across boundaries. Nov 8 comment Trying to model a system of differential equations for outbreaks @xCanaan You're welcome. For a lark, you might want to plot p[t] (which you can get by summing the solutions $s(t) + e(t) + i(t) + r(t)$ just to make sure that the quantity is conserved. It should (numerically) be a horizontal line. Significant deviations would indicate that you need to change methods, e.g. use Method -> "BDF" For some particular parameters and infectious disease models, the equations are remarkably stiff. Nov 8 comment How can I make a smoothed 3D plot from a list of data? The answer of how to interpolate/smooth unstructured data is rather involved. I think for this data set you could use kriging... Nov 8 comment How can I make a smoothed 3D plot from a list of data? Please leave the file on your Dropbox account for a long time, so that when people come to visit this question years from now, the data are still there. Nov 7 comment Trying to model a system of differential equations for outbreaks I think you're closer, not sure if your Initial Value Problem (IVP), e.g. s[0]==p needs the derivatives specified too. Nov 7 comment Update or Animate an ArrayPlot or MatrixPlot? @J.M. Yes, this is preferable if all the data are available at t=0, and the number of additions to the plot are known. I do this sort of thing that I have shown in e.g. monitoring MCMC evolution. Nov 7 comment Trying to model a system of differential equations for outbreaks in your initial conditions, you should have == instead of =. Make sure you quit your Mathematica session before trying to run it again. Nov 7 comment Update or Animate an ArrayPlot or MatrixPlot? Table for what? Data generation? e.g. ListPlot? Nov 5 comment Sparse Cholesky Decomposition A marvelous, helpful answer. Thanks a million!