r.grow: Expose r.mapcalc's nprocs (#6585)

One of the two steps in r.grow is using r.mapcalc. This allows user to control the number of cores used by r.mapcalc in that step (#5742). This is more critical with the default being all cores (#5731) even if the impact is possibly limited given that the main step is not parallelized.

This depends on #6580 for the nprocs parameter in the gs.mapcalc function.

Author: wenzeslaus

scripts/r.grow/r.grow.py

@@ -59,6 +59,8 @@
 # % multiple: no
 # % description: Value to write for "grown" cells
 # %end
+# %option G_OPT_M_NPROCS
+# %end
 
 import os
 import atexit
@@ -83,6 +85,7 @@ def main():
     metric = options["metric"]
     old = options["old"]
     new = options["new"]
+    nprocs = options["nprocs"]
     mapunits = flags["m"]
 
     tmp = str(os.getpid())
@@ -146,6 +149,7 @@ def main():
             old=old,
             new=new,
             dist=temp_dist,
+            nprocs=nprocs,
         )
     else:
         # shrink
@@ -167,6 +171,7 @@ def main():
             radius=radius,
             old=old,
             dist=temp_dist,
+            nprocs=nprocs,
         )
 
     gs.run_command("r.colors", map=output, raster=input)