From 72c125fef689248038dd5daf270f9849fdb43b29 Mon Sep 17 00:00:00 2001 From: Timo Heister Date: Sun, 6 Dec 2015 13:40:34 -0500 Subject: [PATCH] extend step-3 documentation --- examples/step-3/step-3.cc | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/examples/step-3/step-3.cc b/examples/step-3/step-3.cc index 177d05f5a5..b71f63cec9 100644 --- a/examples/step-3/step-3.cc +++ b/examples/step-3/step-3.cc @@ -629,24 +629,26 @@ void Step3::run () // and calling its principle function. // // Finally, the first line of the function is used to enable output of the -// deal.II logstream to the screen. Functions like iterative solvers will -// generate diagnostics (starting residual, number of solver steps, final -// residual), but the display of the logstream to the screen is disabled by -// default. +// deal.II logstream to the screen. The deallog (which stands for deal-log, +// not de-allog) variable represents a stream to which some parts of the +// library write output. For example, iterative solvers will generate +// diagnostics (starting residual, number of solver steps, final residual) as +// can be seen when running this tutorial program. // // The output of deallog can be redirected to the console, to a file, or -// both. The output is nested in a way so that each function can use a prefix -// string (separated by colons) for each line of output; if it calls another -// function, that may also use its prefix which is then printed after the one -// of the calling function. By running this example (or looking at the -// "Results" section), you will see the solver statistics prefixed with -// "DEAL:CG", which is two prefixes. Since output from functions which are -// nested deep below is usually not as important as top-level output, you can -// give the deallog variable a maximal depth of nested output for output to -// console and file. A depth of 0 (the default) will disable output to the -// screen, while a value of 2 or higher will cause the solver info to be -// printed. Imagine that different solvers can be nested, which we will see in -// step-22 for example, and you might not want to see all this information. +// both. But both are disabled by default. The output is nested in a way so +// that each function can use a prefix string (separated by colons) for each +// line of output; if it calls another function, that may also use its prefix +// which is then printed after the one of the calling function. By running +// this example (or looking at the "Results" section), you will see the solver +// statistics prefixed with "DEAL:CG", which is two prefixes. Since output +// from functions which are nested deep below is usually not as important as +// top-level output, you can give the deallog variable a maximal depth of +// nested output for output to console and file. A depth of 0 (the default) +// will disable output to the screen, while a value of 2 or higher will cause +// the solver info in this example to be printed. Imagine that different +// solvers can be nested, which we will see in step-22 for example, and you +// might not want to see all this information. int main () { deallog.depth_console (2); -- 2.39.5