Code refactoring

Author: andrewmurphy353

Makefile

@@ -11,9 +11,8 @@
 # ================================================
 
 # Configuration
-PYTHON := python3.11
-#DOCTEST_FILES := $(wildcard curo/daycount/*.py docs/examples/*.md curo/calculator.py)
-DOCTEST_FILES := $(wildcard docs/tests/example_01.py)
+PYTHON := python3
+DOCTEST_FILES := $(wildcard curo/daycount/*.py curo/calculator.py docs/tests/*.py)
 VENV_DIR := .venv
 UV := uv
 

curo/calculator.py

@@ -217,10 +217,11 @@ def solve_rate(
             UnsolvableError: If no rate can be found within bounds.
 
         Notes:
+            - If called after solve_value, uses the existing profile (if it has a 'factor' column)
+              and sets all is_known to True to ensure validation passes for SOLVE_RATE mode.
+            - Always assigns day count factors based on the provided convention, as it may differ
+              from the convention used in solve_value.
             - Uses scipy.optimize.brentq for root-finding within [-0.9999, upper_bound].
-            - Upper bound is configurable to handle extreme APRs (e.g., usurious loans > 1000%).
-            - Very large upper bounds (e.g., > 100.0) may slow convergence or cause
-                numerical issues.
             - For USAppendixJ, the periodic rate is annualized by multiplying by periods_in_year.
         """
         if upper_bound <= 0.0:
@@ -230,11 +231,20 @@ def solve_rate(
         if self._is_bespoke_profile:
             if not isinstance(self.profile, pd.DataFrame) or self.profile.empty:
                 raise ValidationError("Bespoke profile must be a non-empty DataFrame")
-            cash_flows = self.profile
+            cash_flows = self.profile.copy()
         else:
-            if not self._series:
-                raise ValidationError("No cash flow series provided")
-            cash_flows = self._build_profile(start_date)
+            # Check if profile exists and has a 'factor' column (indicating solve_value was called)
+            if (self.profile is not None and
+                    isinstance(self.profile, pd.DataFrame) and
+                    not self.profile.empty and
+                    ColumnExtras.FACTOR.value in self.profile.columns):
+                cash_flows = self.profile.copy()  # Use existing profile
+                # Set all is_known to True to pass SOLVE_RATE validation
+                cash_flows[Column.IS_KNOWN.value] = True
+            else:
+                if not self._series:
+                    raise ValidationError("No cash flow series provided")
+                cash_flows = self._build_profile(start_date)
 
         sort_by = SortColumn.POST_DATE if convention.use_post_dates else SortColumn.VALUE_DATE
         cash_flows = self._sort_cash_flows(cash_flows, sort_by=sort_by)
@@ -244,7 +254,7 @@ def solve_rate(
             mode=ValidationMode.SOLVE_RATE
             )
 
-        # Assign day count factors
+        # Assign day count factors based on the provided convention
         cash_flows = self._assign_factors(cash_flows, convention)
 
         # Define NFV function for root-finding
@@ -387,8 +397,8 @@ def build_schedule(
                     continue  # Skip charges
                 amount = row[Column.AMOUNT.value]
                 interest = row[ColumnExtras.INTEREST.value]
-                capital = amount - interest
-                capital_balance += interest + amount  # Amount includes sign (negative for advances)
+                capital = amount + interest
+                capital_balance += interest + amount
 
                 schedule.at[
                     idx, ColumnExtras.CAPITAL.value