1 files changed, 83 insertions, 0 deletions
diff --git a/test/random-generator.test b/test/random-generator.test
new file mode 100755
index 00000000..351b982e
--- /dev/null
+++ b/test/random-generator.test
@@ -0,0 +1,83 @@
+#! /bin/sh
+# This script tests: pgmnoise
+# Also requires:
+
+# These tests are for examining the integrity of the random number
+# generator.  There is some overlap between the tests here and tests
+# in pgmnoise.test, but the tests here are better focused for
+# diagnosing problems with the random number generator.
+#
+# Test 1 is for determining the kind of random number generator in
+# use.
+#
+# Test 2 prints random numbers in an output format close to what the
+# test in the original Mersenne Twister code produces.
+#
+# If these tests fail, subsequent tests which depend on random numbers
+# will fail too.  There is no provision (beyond remarks in the script
+# files) for generators other than the Mersenne Twister in those
+# tests.
+
+echo "Test 1: Should produce:"
+
+echo "P2"
+echo "12 1"
+echo "1023"
+echo "720 296 192 858 101 57 298 629 804 1019 64 617"
+echo "Above output is for Mersenne Twister"
+
+pgmnoise -maxval=1023 -randomseed=3791 -plain 12 1
+
+echo
+echo "Test 2: Mersenne Twister random number generator"
+echo "Should produce:"
+
+echo "3499211612  581869302 3890346734 3586334585  545404204"
+echo "4161255391 3922919429  949333985 2715962298 1323567403"
+echo " ... "
+echo " 297480282 1101405687 1473439254 2634793792 1341017984"
+echo " Total 1000 integers, 200 lines"
+echo
+
+# Use perl to avoid mawk limitation
+# (cannot convert 32 bit integers)
+
+perlPgmProcessorProgram='
+  if (($#F+1) == 10) {
+    for (my $i = 0; $i <= 9; $i += 2) {
+      my $r = $F[$i + 1] * 65536 + $F[$i];
+      printf "%10u ", $r;
+    }
+    print "";
+  }
+'
+
+pgmnoise -randomseed=5489 -plain -maxval=65535 10 200 | \
+  perl -walne "$perlPgmProcessorProgram"
+
+# The above outputs (10 * 200 / 2) = 1000 samples.
+
+#    Method to generate output for Test 2 from original
+#    Mersenne Twister source code
+#
+# Download Mersenne Twister code.  See lib/util/randmersenne.c for URL.
+# Edit mt19937ar.c:
+#   In function main() at bottom of file, replace
+#     init_by_array(init, length);
+#   with
+#     init_genrand(5489UL);
+#
+# We need only the output of genrand_int32().
+# Remove the second loop which produces double-precision floating point
+# random numbers with genrand_real2().
+#
+# Compile: gcc mt19937ar.c -o mt1000
+# Execute: ./mt1000
+
+# 1000 may seem like a large number of samples but there is a reason
+# for this.  The generator produces random integers in batches of 624.
+# The number of samples must be larger than 624 to ensure proper
+# generation in batches after the first.
+
+# If you encounter problems, adjust the 200 (rows) above and tweak
+# the code in mt19937ar.c accordingly to produce more random numbers.