/* Last updated: January 25, 2021 by Hereman in Boulder */ /* For use with symmgrp2020.max under Maxima */ /* File name: p5diffusion-run4-Jan25-2021-wh.dat. */ /* Data file for diffusion equation with power 5 diffusivity given in the online manuscript Faruk Gungor. */ /* u_t - x^5 u_xx + x u_y = 0 */ /* Assign u[1] to u, x[1] to x, x[2] to y, and x[3] to t. */ /* number of independent variables: */ p : 3$ /* number of dependent variables: */ q : 1$ /* number of equations in the system: */ m : 1$ warnings: false$ parameters : [] $ sublisteqs : [all]$ subst_deriv_of_vi: true$ highest_derivatives : all$ /* information is given. */ info_given : true$ depends([eta1,f1,f2],[x[1],x[2],x[3]]); depends([eta2,g1],x[2]); depends([g2,eta3],[x[2],x[3]]); /* f2 must satisfy the original equation itself. */ /* We will bring that back only at the end to avoid that this constraint is repeated every time. */ gradef(f2,x[3],x[1]^5*diff(f2,x[1],2)-x[1]*diff(f2,x[2])); /* f1 must also satisfy the original equation and we need to take that into account in a few runs. */ /* gradef(f1,x[3],x[1]^5*diff(f1,x[1],2)-x[1]*diff(f1,x[2])); */ f1 : -(1/2)*(1/x[1])*diff(g1,x[2],2)-x[1]*diff(g1,x[2])-(3/4)*(x[3]/x[1])*diff(eta2,x[2],3)-(3/2)*x[1]*x[3]*diff(eta2,x[2],2)-(1/(2*x[1]^2))*diff(eta2,x[2],2)+g2; eta3 : (3/2)*diff(eta2,x[2])*x[3]+g1; eta1 : -x[1]*diff(eta3,x[3])-x[1]^2*diff(eta3,x[2])+diff(eta2,x[3])+x[1]*diff(eta2,x[2]); phi1 : f1*u[1]+f2; e1 : u[1,[0,0,1]]-x[1]^5*u[1,[2,0,0]]+x[1]*u[1,[0,1,0]]; /* eliminate u_t */ v1 : u[1,[0,0,1]]; /* end of data file p5diffusion-run4-Jan25-2021-wh.dat. */