diff --git a/README.md b/README.md
index e69de29..5993c28 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,26 @@
+Rust implementation for the approximate greatest common divisor (AGCD) problem using LLL algorithm.
+
+## commands
+
+*use the provided Makefile to compile the release version*
+
+```
+approximate-gcd agcd <path to input file>
+```
+
+Input file must have the following format:
++ first non-comment line: number of noise bits (written in decimal)
++ all the other lines, one per line: the numbers Xi (written in decimal) to find the approximate GCD of
++ ```//``` can be used to comment a line, MUST be used at the begining of a new line and not at the end of a line containing a number
+
+### generating values
+The script gen_values can be used to generate test values
+
+```
+python gen_values.py [--noise-bits <number of noise bits>] [--number <number of values to generate>]
+```
+
+the output can be directly written to a file
+```
+python gen_values.py [options] > input.txt
+```
diff --git a/gen_values.py b/gen_values.py
index f73c9a2..1fa4602 100644
--- a/gen_values.py
+++ b/gen_values.py
@@ -4,9 +4,9 @@ import argparse
 
 def generate_test_file(noise_bits, number):
 
-    p = random.randint(100, 1000)
+    p = random.randint(1000, 10000)
     while p % 2 == 0:
-        p = random.randint(100, 1000)
+        p = random.randint(1000, 10000)
 
     max_noise = (1 << noise_bits) - 1  # 2^noise_bits - 1
 
diff --git a/src/matrix.rs b/src/matrix.rs
index 7b4224f..91b207a 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -120,11 +120,11 @@ mod tests {
             int!(8),
             int!(12),
             int!(0),
-            int!(-5),
+            int!(5),
             int!(0),
             int!(0),
             int!(0),
-            int!(-5),
+            int!(5),
         ];
 
         let lattice = Matrix::new_lattice(noise_bits, ciphertexts).unwrap();