 PepeToro

Trying to learn math :)

 2018 Aug 27 awarded Popular Question Jun 26 comment Non affine control?Thanks!, indeed I would like to tackle the case when f(x,t) is bounded but may be zero. Probably I can assume that f(x,t) is zero only on a set of measure zero... but I would be interested on not so restrictive cases, if they have been studied. Jun 25 asked Non affine control? Jan 29 accepted Use string to select a function and/or a variable (Julia) Jan 29 accepted eigenvalues weighted ring graph Jan 27 comment eigenvalues weighted ring graphThanks. However, even for the weighted case, eigenvectors are still orthogonal. So, in some sense I would have expected that the "Fourier" description of eigenvectors still holds, while naturally the weights would then "only" affect the eigenvalues. Jan 26 revised eigenvalues weighted ring graphadded 31 characters in body Jan 26 asked eigenvalues weighted ring graph Dec 11 asked Use string to select a function and/or a variable (Julia) Nov 14 awarded Critic Sep 20 awarded Nice Question Aug 22 awarded Notable Question Aug 16 awarded Autobiographer Aug 5 awarded Yearling Aug 5 awarded Yearling Mar 16 comment Drawing directions fields@RicardoAcuna the U,V formulas in the program are exclusively for the arrows and are exactly equal to the equations of the vf (vector field) function. So, if you want to plot a similar picture, say for \$(x',y')=(f_1(x,y),f_2(x,y))\$ write \$(U,V)=(f_1(X,Y),f_2(X,Y)\$. Note that I use big \$(X,Y)\$ to denote the coordinates of the mesh. Then, you use \$N\$ to normalise the arrows, so that all of them have the same length. Therefore, it is important to note that the picture you get is for a normalised vector field in which only the direction is shown but not the velocity itself. Hope this helps. Feb 26 comment Drawing directions fields@RicardoAcuna U=1 because of the particular example. The part that follows #Vector field is exclusively to draw the arrows in accordance to the definition of #Vector field function. Of course changing vf(t,x) should be followed by an appropriate change of U,V Feb 20 accepted Sufficient conditions for global stability from linear stability. Feb 19 asked Sufficient conditions for global stability from linear stability. Feb 6 revised Transforming linear dynamical system to reduce magnitude of eigen valuesadded 1 character in body