Update error label and fix some io related issue

Author: sirno

src/core/fitness/epistasis.rs

@@ -85,15 +85,15 @@ impl EpistasisTable {
             .shape(&shape)
             .writer(writer)
             .begin_nd()
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
 
         // Write entries to file
         npy_writer
             .extend(entries)
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
         npy_writer
             .finish()
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
 
         Ok(())
     }

src/core/fitness/table.rs

@@ -93,13 +93,13 @@ impl FitnessTable {
             .shape(shape)
             .writer(writer)
             .begin_nd()
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
         npy_writer
             .extend(self.table.clone())
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
         npy_writer
             .finish()
-            .map_err(|e| VirolutionError::InitializationError(format!("{}", e)))?;
+            .map_err(|e| VirolutionError::WriteError(format!("{}", e)))?;
         Ok(())
     }
 }

src/errors.rs

@@ -9,6 +9,7 @@ pub enum VirolutionError {
     ImplementationError(String),
     InitializationError(String),
     ReadError(String),
+    WriteError(String),
 }
 
 impl fmt::Display for VirolutionError {
@@ -23,6 +24,9 @@ impl fmt::Display for VirolutionError {
             VirolutionError::ReadError(message) => {
                 write!(f, "ReadError: {}", message)
             }
+            VirolutionError::WriteError(message) => {
+                write!(f, "WriteError: {}", message)
+            }
         }
     }
 }

src/runner.rs

@@ -212,9 +212,17 @@ impl Runner {
     }
 
     fn write_fitness_tables(providers: &[&FitnessProvider], path: Option<&Path>) {
-        let sequence_path = path.unwrap_or_else(|| Path::new("./"));
+        let write_path = path.unwrap_or_else(|| Path::new("./"));
+
+        // create output directory
+        fs::create_dir_all(write_path).unwrap_or_else(|_| {
+            eprintln!("Unable to create output directory.");
+            std::process::exit(1);
+        });
+
+        // write fitness tables
         providers.iter().for_each(|provider| {
-            provider.write(sequence_path).unwrap();
+            provider.write(write_path).unwrap();
         });
     }