# Clawpack Makefiles¶

Makefiles for the Fortran code in many repositories use the common Makefile found in $CLAW/clawutil/src/Makefile.common, so you must have the clawutil repository. New in 5.4.0. The Makefile also typically refers to a common list of library routines needed for this particular example or application code, rather than listing all the files individually in every Makefile. See Library routines in Makefiles for more details on how to specify local files in place of library files if you need to replace a default file. In most directories with a Makefile you can type: $ make help


to find out what options are available.

## Applications directory Makefiles¶

### output¶

In applications directories, compiling and running the code can usually be accomplished via:

$make .output  This checks dependencies using the data of the hidden file .output that is created after the code has successfully run. If any Fortran codes have been modified since this date, the code is first recompiled. If the setrun.py script has been changed more recently, then the data files are first recreated. If you want to re-run the code and you get: $ make .output
make: .output' is up to date.


then you can force it to run again by removing the file .output:

$rm -f .output$ make .output


This happens for example if you changed something that you know will affect the output but that isn’t in the Makefile’s set of dependencies, or if the code bombed or was aborted before completion.

The hidden file .output contains a single line, which is the path to the directory where the output resides (as specified by the CLAW_outdir variable in the Makefile). This file is used by the interactive plotting routines, as described in Plotting with Visclaw.

You can also do:

$make output  (with no dot before output) to run the code without checking dependencies. This is sometimes handy but note that if you modify the setrun function and then do make output, it will not use the new parameter values. You must do make .data to regenerate the data files used by Clawpack. This would be done automatically by make .output, for which .data is a dependency. ### plots¶ In applications directories, plotting results computed by Clawpack can generally be accomplished via: $ make .plots


This checks dependencies using the date of the hidden file .plots.

This creates a set of webpages that show the plots, as described further in Plotting with Visclaw. There are other interactive plotting options also described there.

Starting in 4.5.1, you can also do

$make plots (with no dot before plots) to plot the output without checking dependencies. This insures that the code will not be run again and is sometime safer than make .plots, which may attempt to run the code if something appears out of date. ### Variables¶ A number of variables are defined in the Makefiles of application directories. For example, output is directed to the subdirectory specified by the variable OUTDIR. To change this, simply modify the Makefile before typing “make .output”. Alternatively, you can modify the variable from the command line, e.g.: $ make .output OUTDIR=run1


to direct output to a subdirectory named run1.

### Compiler flags¶

Compiler flags can be changed by modifying the FFLAGS variable in the Makefile. If you change compiler flags you will generally need to recompile all the Fortran files and the Makefile dependencies will not detect this. To force recompilation of all files, use the “make new” option, e.g. to recompile with the -g flag for debugging:

\$ make new FFLAGS=-g
`

See Fortran Compilers for more about compiler flags.

### Duplicate Base Source Name¶

Fortran source files with the same base name but different suffixes can cause unexpected source files to be compiled. This occurs as the Makefiles are structured to use the free-format Fortran source files .f90* before the fixed-format source files with *.f*. For example, if someone specified *qinit.f* in the Makefile but there was a *qinit.f90* file that existed in the same directory then the compiler would compile the **f90 file instead of the f file.

The best way to avoid this problem is to check periodically whether you may have conlicting source via the make debug command which should list possible conflicts. Note that this command will also list sources that may not be in conflict. If you do have conflicting source either remove the f90 file, rename it, or convert the f file into a f90 file.