diff options
| -rw-r--r-- | doc/documentation.tex | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex index 519a092..0f80e0d 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -28,6 +28,16 @@ derivatives {\bf psixx}, {\bf psixy}, {\bf psixz}, {\bf psiyy}, {\bf psiyz}, and {\bf psizz} depending on the setting of the {\bf conformal\_storage} parameter. +Note that the first and second ``derivative'' grid functions have an +additional factor of $1 / \psi$ normalisation since this is the most +common use of the derivative. I.e. the grid functions are + +$$ \psi $$ +$$ \psi_i/\psi$$ +and + +$$ \psi_{ij}/\psi $$ + Thorns need to check the value of the grid scalar {\bf conformal\_state} to determine how many levels of these variables have actually been calculated. @@ -49,6 +59,19 @@ The conformal factor and its first and second derivatives have been calculated. The {\bf StaticConformal} thorn itself does not calculate any conformal factor, but does initialise the {\bf conformal\_state} variable to 0. +Please note, no thorn should use the conformal\_state variable unless +metric\_type is "static conformal". The conformal\_state variable is +not assigned storage or initialised by the StaticConformal thorn in +any other case. + +However thorns are free to themselves assigned storage for +conformal\_state and initialised it to zero if metric\_type is +"physical". In this one case is it safe for them to use +the conformal\_state variable if metric\_type is not "static +conformal". This method allows them to use just one set of ifs rather +than first checking the metric\_type and then the conformal\_state +variable if the metric\_type is "static conformal". + % Automatically created from the ccl files by using gmake thorndoc \include{interface} \include{param} |