r.surf.gauss: Added seed option and flag (#2931)

* r.surf.gauss: Added seed option and flag

* Updated seed options, flags and tests

* r.surf.gauss: switch seed to long from int

* Update raster/r.surf.gauss/main.c

Co-authored-by: Anna Petrasova <[email protected]>

* Changed message to warning

* Change to G_warning

* Update test to check univar stats

* Updated tests to check default params univar stats

* Removed random seed flag -s

* Updated warning message and copywrite

* Fixed typo

* Update raster/r.surf.gauss/main.c

Co-authored-by: Anna Petrasova <[email protected]>

* Change test file name to meet convention

* Reduced the extent of the test raster to speed up tests

* Apply suggestions from code review

* Removed old comment

* change the tests to use fixed reference values

---------

Co-authored-by: Corey White <[email protected]>
Co-authored-by: Anna Petrasova <[email protected]>

raster/r.surf.gauss/gaussurf.c

@@ -29,11 +29,6 @@ int gaussurf(char *out, /* Name of raster maps to be opened.    */
 
     int row_count, col_count;
 
-    /****** INITIALISE RANDOM NUMBER GENERATOR ******/
-
-    /* You can set GRASS_RANDOM_SEED for repeatability */
-    G_math_srand_auto();
-
     /****** OPEN CELL FILES AND GET CELL DETAILS ******/
 
     fd_out = Rast_open_new(out, DCELL_TYPE);

raster/r.surf.gauss/main.c

@@ -24,11 +24,13 @@ int main(int argc, char *argv[])
 
     /****** INITIALISE ******/
     double gauss_mean, gauss_sigma;
+    long seed_value;
 
     struct GModule *module;
     struct Option *out;
     struct Option *mean;
     struct Option *sigma;
+    struct Option *seed;
 
     G_gisinit(argv[0]);
 
@@ -55,9 +57,31 @@ int main(int argc, char *argv[])
     sigma->type = TYPE_DOUBLE;
     sigma->answer = "1.0";
 
+    seed = G_define_option();
+    seed->key = "seed";
+    seed->type = TYPE_INTEGER;
+    seed->required = NO;
+    seed->label = _("Seed for random number generator");
+    seed->description = _("The same seed can be used to obtain same results"
+                          " or random seed can be generated by other means.");
+
     if (G_parser(argc, argv))
         exit(EXIT_FAILURE);
 
+    /****** INITIALISE RANDOM NUMBER GENERATOR ******/
+    if (seed->answer) {
+        seed_value = atol(seed->answer);
+        G_srand48(seed_value);
+        G_verbose_message(_("Read random seed from %s option: %ld"), seed->key,
+                          seed_value);
+    }
+    else {
+        /* default as it used to be */
+        seed_value = G_math_srand_auto();
+        G_verbose_message(_("Autogenerated random seed set to: %ld"),
+                          seed_value);
+    }
+
     sscanf(mean->answer, "%lf", &gauss_mean);
     sscanf(sigma->answer, "%lf", &gauss_sigma);
 

raster/r.surf.gauss/testsuite/test_r_surf_gauss.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+
+"""
+MODULE:    Test of r.surf.gauss
+
+AUTHOR(S): Corey White <ctwhite48 gmail com>
+
+PURPOSE: Tests random gauss surface generation
+
+COPYRIGHT: (C) 2023 - 2024 by Corey White and the GRASS Development Team
+
+This program is free software under the GNU General Public
+License (>=v2). Read the file COPYING that comes with GRASS
+for details.
+"""
+
+import os
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
+
+
+class MeanSigmaTestCase(TestCase):
+    """Test r.surf.gauss module"""
+
+    # Raster map name be used as output
+    output = "random_result"
+
+    @classmethod
+    def setUpClass(cls):
+        """Ensures expected computational region"""
+        os.environ["GRASS_RANDOM_SEED"] = "42"
+        # modifying region just for this script
+        cls.use_temp_region()
+        cls.runModule("g.region", rows=10, cols=10)
+
+    @classmethod
+    def tearDownClass(cls):
+        """Remove the temporary region"""
+        cls.del_temp_region()
+
+    def tearDown(self):
+        """Remove the output created from the module"""
+        self.runModule("g.remove", flags="f", type="raster", name=[self.output])
+
+    def test_defaut_settings(self):
+        """Check to see if univariate statistics match for default"""
+        self.assertModule("r.surf.gauss", output=self.output)
+        self.assertRasterFitsUnivar(
+            self.output,
+            reference=dict(mean=-0.044860, stddev=1.019485),
+            precision=1e-6,
+        )
+
+    def test_mean_sigma_params(self):
+        """Check if mean and sigma params are accepted"""
+        mean_value = 3.0
+        sigma_value = 5.8
+        self.assertModule(
+            "r.surf.gauss",
+            mean=mean_value,
+            sigma=sigma_value,
+            output=self.output,
+        )
+        self.assertRasterExists(self.output, msg="Output was not created")
+        self.assertRasterFitsUnivar(
+            self.output,
+            reference=dict(mean=2.739812, stddev=5.913014),
+            precision=1e-6,
+        )
+
+    def test_random_seed_option(self):
+        """Checks if random seed option sets random number"""
+        mean_value = 3.0
+        sigma_value = 5.8
+        self.assertModule(
+            "r.surf.gauss",
+            mean=mean_value,
+            sigma=sigma_value,
+            output=self.output,
+            seed=22,
+        )
+        self.assertRasterExists(self.output, msg="Output was not created")
+        self.assertRasterFitsUnivar(
+            self.output,
+            reference=dict(mean=3.183532, stddev=6.050756),
+            precision=1e-6,
+        )
+
+
+if __name__ == "__main__":
+    test()