From ce40c7b3f367fd79d4b8f59efeadd409d001449c Mon Sep 17 00:00:00 2001
From: MatteoRobbiati <robbiati.matteo@gmail.com>
Date: Tue, 28 Jan 2025 22:16:11 +0100
Subject: [PATCH] fix: TensorNetworkResult error raising

---
 src/qibotn/result.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/qibotn/result.py b/src/qibotn/result.py
index b140601..078f2e1 100644
--- a/src/qibotn/result.py
+++ b/src/qibotn/result.py
@@ -22,13 +22,22 @@ class TensorNetworkResult:
             self.measured_probabilities = {"default": self.measured_probabilities}
 
     def probabilities(self):
+        """Return calculated probabilities according to the given method."""
         return self.measured_probabilities[self.prob_type]
 
     def frequencies(self):
-        return self.measures
+        """Return frequencies if a certain number of shots has been set."""
+        if self.measures is None:
+            raise_error(
+                ValueError,
+                f"To access frequencies, circuit has to be executed with a given number of shots != None",
+            )
+        else:
+            return self.measures
 
     def state(self):
-        if self.nqubits < 30:
+        """Return the statevector if the number of qubits is less than 30."""
+        if self.nqubits < 20:
             return self.statevector
         else:
             raise_error(