Added ability to load Percolator model

mokapot/model.py

@@ -12,6 +12,8 @@ class that contains this logic. A :py:class:`Model` instance can be
 import logging
 import pickle
 
+import numpy as np
+import pandas as pd
 import sklearn.base as base
 import sklearn.svm as svm
 import sklearn.model_selection as ms
@@ -303,7 +305,11 @@ def save_model(model, out_file):
 
 def load_model(model_file):
     """
-    Load a saved :py:class:`mokapot.model.Model` object.
+    Load a saved model for mokapot.
+
+    The saved model can either be a saved :py:class:`mokapot.model.Model`
+    object or the output model weights from Percolator. In Percolator,
+    these can be obtained using the :code:`--weights` argument.
 
     Parameters
     ----------
@@ -315,8 +321,26 @@ def load_model(model_file):
     mokapot.model.Model
         The loaded :py:class:`mokapot.model.Model` object.
     """
-    with open(model_file, "rb") as mod_in:
-        model = pickle.load(mod_in)
+    # Try a percolator model first:
+    try:
+        weights = pd.read_csv(model_file, sep="\t", nrows=2).loc[1, :]
+        logging.info("Loading the Percolator model.")
+
+        weight_cols = [c for c in weights.index if c != "m0"]
+        model = Model(estimator=svm.LinearSVC(), scaler="as-is",
+                      is_trained=True)
+
+        weight_vals = weights.loc[weight_cols]
+        weight_vals = weight_vals[np.newaxis, :]
+        model.estimator.coef_ = weight_vals
+        model.estimator.intercept_ = weights.loc["m0"]
+        model.features = weight_cols
+
+    # Then try loading it with pickle:
+    except UnicodeDecodeError:
+        logging.info("Loading mokapot model.")
+        with open(model_file, "rb") as mod_in:
+            model = pickle.load(mod_in)
 
     return model