update readme and min number of signature when using --signature-name…

…s option

README.rst

@@ -5,7 +5,7 @@ StarSignDNA
 Mutation signature analysis package
 -----------------------------------
 
-* Free software: MIT license
+* Free software: `MIT license <https://opensource.org/licenses/MIT>`_
 * Documentation: Link to be provided
 
 Features
@@ -21,6 +21,9 @@ To install StarSign, run this command in your terminal::
     3. cd StarSigndna-master/
     4. pip install -e .
 
+Alternatively, you can install the package directly from PyPi::
+
+    pip install starsigndna
 Getting started
 ---------------
 

mutational_starsign/cli.py

@@ -450,13 +450,10 @@ def read_counts(matrix_file):
     M = pd.read_csv(matrix_file, delimiter='\t')
     return M
 
-def filter_signatures_old(S, signature_names):
-    S = S.loc[signature_names]
-    return S
 
 def filter_signatures(S, signature_names):
-    if len(signature_names) < 5:
-        raise ValueError("You must select at least 5 signature names.")
+    if len(signature_names) < 3:
+        raise ValueError("You must select at least 3 signature names.")
     S = S.loc[signature_names]
     return S