* Here we test manipulations on GiNaC's indexed objects. */
/*
- * GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2020 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
symbol Bx("Bx"), By("By"), Bz("Bz");
// Lorentz transformation matrix (boost along x axis)
- matrix L(4, 4);
- L = gamma, -beta*gamma, 0, 0,
- -beta*gamma, gamma, 0, 0,
- 0, 0, 1, 0,
- 0, 0, 0, 1;
+ matrix L = {{ gamma, -beta*gamma, 0, 0},
+ {-beta*gamma, gamma, 0, 0},
+ { 0, 0, 1, 0},
+ { 0, 0, 0, 1}};
// Electromagnetic field tensor
- matrix F(4, 4);
- F = 0, -Ex, -Ey, -Ez,
- Ex, 0, -Bz, By,
- Ey, Bz, 0, -Bx,
- Ez, -By, Bx, 0;
+ matrix F = {{ 0, -Ex, -Ey, -Ez},
+ {Ex, 0, -Bz, By},
+ {Ey, Bz, 0, -Bx},
+ {Ez, -By, Bx, 0}};
// Indices
symbol s_mu("mu"), s_nu("nu"), s_rho("rho"), s_sigma("sigma");
* indexed(F, rho, sigma)).simplify_indexed();
// Extract transformed electric and magnetic fields
- ex Ex_p = e.subs(lst(mu == 1, nu == 0)).normal();
- ex Ey_p = e.subs(lst(mu == 2, nu == 0)).normal();
- ex Ez_p = e.subs(lst(mu == 3, nu == 0)).normal();
- ex Bx_p = e.subs(lst(mu == 3, nu == 2)).normal();
- ex By_p = e.subs(lst(mu == 1, nu == 3)).normal();
- ex Bz_p = e.subs(lst(mu == 2, nu == 1)).normal();
+ ex Ex_p = e.subs(lst{mu == 1, nu == 0}).normal();
+ ex Ey_p = e.subs(lst{mu == 2, nu == 0}).normal();
+ ex Ez_p = e.subs(lst{mu == 3, nu == 0}).normal();
+ ex Bx_p = e.subs(lst{mu == 3, nu == 2}).normal();
+ ex By_p = e.subs(lst{mu == 1, nu == 3}).normal();
+ ex Bz_p = e.subs(lst{mu == 2, nu == 1}).normal();
// Check results
result += check_equal(Ex_p, Ex);
// Test 2: check energy density and Poynting vector of electromagnetic field
// Minkowski metric
- ex eta = diag_matrix(lst(1, -1, -1, -1));
+ ex eta = diag_matrix(lst{1, -1, -1, -1});
// Covariant field tensor
ex F_mu_nu = (indexed(eta, mu.toggle_variance(), rho.toggle_variance())
// Energy-momentum tensor
ex T = (-indexed(eta, rho, sigma) * F_mu_nu.subs(s_nu == s_rho)
- * F_mu_nu.subs(lst(s_mu == s_nu, s_nu == s_sigma))
+ * F_mu_nu.subs(lst{s_mu == s_nu, s_nu == s_sigma})
+ indexed(eta, mu.toggle_variance(), nu.toggle_variance())
- * F_mu_nu.subs(lst(s_mu == s_rho, s_nu == s_sigma))
+ * F_mu_nu.subs(lst{s_mu == s_rho, s_nu == s_sigma})
* indexed(F, rho, sigma) / 4).simplify_indexed() / (4 * Pi);
// Extract energy density and Poynting vector
- ex E = T.subs(lst(s_mu == 0, s_nu == 0)).normal();
- ex Px = T.subs(lst(s_mu == 0, s_nu == 1));
- ex Py = T.subs(lst(s_mu == 0, s_nu == 2));
- ex Pz = T.subs(lst(s_mu == 0, s_nu == 3));
+ ex E = T.subs(lst{s_mu == 0, s_nu == 0}).normal();
+ ex Px = T.subs(lst{s_mu == 0, s_nu == 1});
+ ex Py = T.subs(lst{s_mu == 0, s_nu == 2});
+ ex Pz = T.subs(lst{s_mu == 0, s_nu == 3});
// Check results
result += check_equal(E, (Ex*Ex+Ey*Ey+Ez*Ez+Bx*Bx+By*By+Bz*Bz) / (8 * Pi));
// GiNaC 1.2.1 had a bug here because p.i*p.i -> (p.i)^2
e = indexed(p, i) * indexed(p, i) * indexed(p, j) + indexed(p, j);
ex fi = exprseq(e.get_free_indices());
- if (!fi.is_equal(exprseq(j))) {
+ if (!fi.is_equal(exprseq{j})) {
clog << "get_free_indices(" << e << ") erroneously returned "
<< fi << " instead of (.j)" << endl;
++result;