diff options
| -rw-r--r-- | doc/documentation.tex | 13 | ||||
| -rw-r--r-- | src/metrics/Minkowski_gauge_wave.F77 | 36 |
2 files changed, 22 insertions, 27 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex index 3467456..a10b8db 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -533,15 +533,16 @@ The line element is \begin{equation} ds^2=-H dt^2 +Hdx^2+dy^2+dz^2, \end{equation} -where $H=H(x-t)$, for instance $H=1-a*\sin\big((x-t)/d\big)$. +where $H=H(x-t)$, for instance $H=1-a\sin\left((x-t)/\Lambda\right)$. This is flat space but the slice is a planar wave travelling along the x axis. This thorn implements several possible choices for the $H$ function, controlled by the \verb|Minkowski_gauge_wave__what_fn| parameter: \begin{eqnarray} -H(x-t) &=& 1- A \sin \left(\frac{x-t}{d}\right) \\ -H(x-t) &=& \exp \left(A*sin(x)*cos(x)\right) \\ -H(x-t) &=& 1- A exp(-x^2) %%%\\ +H(x-t) &=& 1 - A \sin \left(\frac{x-\omega t}{\Lambda} - \delta\right) \\ +H(x-t) &=& \exp \left(- A \sin \left(\frac{x-\omega t}{\Lambda} + - \delta\right)\right) \\ +H(x-t) &=& 1 - A \exp(-x^2) %%%\\ \end{eqnarray} The parameters are \begin{itemize} @@ -550,10 +551,6 @@ The parameters are \item $\lambda = \verb|Minkowski_gauge_wave__lambda|$, the wavelength \item $\delta = \verb|Minkowski_gauge_wave__phase|$, the phase shift \end{itemize} -Unfortunately, you have to look at the source code to see exactly what -these do. :( -FIXME: someone reverse-engineer the code and change the equations above -to match whatever the code actually does. If the Boolean parameter \verb|Minkowski_gauge_wave__diagonal| is true, then we make the gauge wave travel diagonally across the grid by the diff --git a/src/metrics/Minkowski_gauge_wave.F77 b/src/metrics/Minkowski_gauge_wave.F77 index 6ef07be..f4b6360 100644 --- a/src/metrics/Minkowski_gauge_wave.F77 +++ b/src/metrics/Minkowski_gauge_wave.F77 @@ -36,11 +36,8 @@ c output arguments CCTK_REAL psi LOGICAL Tmunu_flag -c local static variables - logical firstcall +c local parameter copies CCTK_REAL a, o, d, fs - data firstcall /.true./ - save firstcall, a, o, d, fs c local variables CCTK_REAL H @@ -54,29 +51,30 @@ C This is a vacuum spacetime with no cosmological constant Tmunu_flag = .false. C Get parameters of the exact solution. - - if (firstcall) then - a = Minkowski_gauge_wave__amplitude - o = Minkowski_gauge_wave__omega - d = Minkowski_gauge_wave__lambda - fs = Minkowski_gauge_wave__phase - - firstcall = .false. - end if + a = Minkowski_gauge_wave__amplitude + o = Minkowski_gauge_wave__omega + d = Minkowski_gauge_wave__lambda + fs = Minkowski_gauge_wave__phase C How should the wave look like. - if (CCTK_Equals(Minkowski_gauge_wave__what_fn,"sin").eq.1) then + if (CCTK_EQUALS(Minkowski_gauge_wave__what_fn,"sin")) then d = Minkowski_gauge_wave__lambda * half / Pi if (Minkowski_gauge_wave__diagonal.ne.0) then - H = one - a * sin((x-y)/d - o*t/d) + H = one - a * sin((x-y)/d - o*t/d - fs) else H = one - a * sin((x-o*t)/d - fs) end if - elseif (CCTK_Equals(Minkowski_gauge_wave__what_fn,"expsin").eq.1) then + elseif (CCTK_EQUALS(Minkowski_gauge_wave__what_fn,"expsin")) then +c$$$ d = Minkowski_gauge_wave__lambda * half / Pi +c$$$ H = exp(a*sin(x/d)*cos(t/d)) d = Minkowski_gauge_wave__lambda * half / Pi - H = exp(a*sin(x/d)*cos(t/d)) - elseif (CCTK_Equals(Minkowski_gauge_wave__what_fn,"Gaussian").eq.1) then - H = one - a*dexp(-(x-t)**2/d**2) + if (Minkowski_gauge_wave__diagonal.ne.0) then + H = exp(- a * sin((x-y)/d - o*t/d - fs)) + else + H = exp(- a * sin((x-o*t)/d - fs)) + end if + elseif (CCTK_EQUALS(Minkowski_gauge_wave__what_fn,"Gaussian")) then + H = one - a*exp(-(x-t)**2/d**2) else write (warn_buffer, '(a,a,a)') $ 'Unknown Minkowski_gauge_wave__what_fn = "', |