add select and net_present_value functions

Author: gabrielaznar

climada/entity/disc_rates/base.py

@@ -15,7 +15,8 @@
 from climada.util.files_handler import to_list, get_file_names
 import climada.util.checker as check
 from climada.entity.tag import Tag
-import climada.util.plot as plot
+import climada.util.plot as u_plot
+import climada.util.finance as u_fin
 
 LOGGER = logging.getLogger(__name__)
 
@@ -100,6 +101,27 @@ def read(self, files, descriptions='', var_names=None):
         for file, desc, var in zip(all_files, desc_list, var_list):
             self.append(self._read_one(file, desc, var))
 
+    def select(self, year_range):
+        """Select discount rates in given years.
+
+        Parameters:
+            year_range (np.array): continuous sequence of selected years.
+
+        Returns:
+            DiscRates
+        """
+        pos_year = np.isin(year_range, self.years)
+        if not np.all(pos_year):
+            LOGGER.info('No discount rates for given years.')
+            return None
+        pos_year = np.isin(self.years, year_range)
+        sel_disc = self.__class__()
+        sel_disc.tag = self.tag
+        sel_disc.years = self.years[pos_year]
+        sel_disc.rates = self.rates[pos_year]
+
+        return sel_disc
+
     def append(self, disc_rates):
         """Check and append discount rates to current DiscRates. Overwrite
         discount rate if same year.
@@ -130,6 +152,29 @@ def append(self, disc_rates):
         self.years = np.append(self.years, new_year).astype(int, copy=False)
         self.rates = np.append(self.rates, new_rate)
 
+    def net_present_value(self, ini_year, end_year, val_years):
+        """Compute net present value between present year and future year.
+
+        Parameters:
+            ini_year (float): initial year
+            end_year (float): end year
+            val_years (np.array): cash flow at each year btw ini_year and
+                end_year (both included)
+        Returns:
+            float
+        """
+        year_range = np.arange(ini_year, end_year+1)
+        if year_range.size != val_years.size:
+            LOGGER.info('Wrong size of yearly values.')
+            return None
+        sel_disc = self.select(year_range)
+        if sel_disc is None:
+            LOGGER.info('No information of discount rates for provided years:'\
+                        ' %s - %s', ini_year, end_year)
+            return None
+        return u_fin.net_present_value(sel_disc.years, sel_disc.rates,
+                                       val_years)
+
     @staticmethod
     def get_sup_file_format():
         """ Get supported file extensions that can be read.
@@ -141,7 +186,7 @@ def get_sup_file_format():
 
     def plot(self):
         """Plot discount rates per year."""
-        graph = plot.Graph2D('Discount rates')
+        graph = u_plot.Graph2D('Discount rates')
         graph.add_subplot('Year', 'discount rate (%)', '')
         graph.add_curve(self.years, self.rates * 100, 'b')
         graph.set_x_lim(self.years)

climada/entity/disc_rates/test/test_base.py

@@ -35,22 +35,22 @@ def test_attributes_all(self):
 
     def test_get_def_vars(self):
         """ Test def_source_vars function."""
-        self.assertTrue(DiscRates.get_def_file_var_names('xls') == 
+        self.assertTrue(DiscRates.get_def_file_var_names('xls') ==
                         READ_SET['XLS'][0])
-        self.assertTrue(DiscRates.get_def_file_var_names('.mat') == 
+        self.assertTrue(DiscRates.get_def_file_var_names('.mat') ==
                         READ_SET['MAT'][0])
 
 class TestAppend(unittest.TestCase):
     """Check append function"""
     def test_append_to_empty_same(self):
-        """Append DiscRates to empty one."""     
+        """Append DiscRates to empty one."""
         disc_rate = DiscRates()
         disc_rate_add = DiscRates()
         disc_rate_add.tag.file_name = 'file1.txt'
         disc_rate_add.tag.description = 'descr1'
         disc_rate_add.years = np.array([2000, 2001, 2002])
         disc_rate_add.rates = np.array([0.1, 0.2, 0.3])
-        
+
         disc_rate.append(disc_rate_add)
         disc_rate.check()
 
@@ -62,7 +62,7 @@ def test_append_to_empty_same(self):
                                        disc_rate_add.tag.description))
 
     def test_append_equal_same(self):
-        """Append the same DiscRates. The inital DiscRates is obtained."""     
+        """Append the same DiscRates. The inital DiscRates is obtained."""
         disc_rate = DiscRates()
         disc_rate.tag.file_name = 'file1.txt'
         disc_rate.tag.description = 'descr1'
@@ -74,7 +74,7 @@ def test_append_equal_same(self):
         disc_rate_add.tag.description = 'descr1'
         disc_rate_add.years = np.array([2000, 2001, 2002])
         disc_rate_add.rates = np.array([0.1, 0.2, 0.3])
-        
+
         disc_rate.append(disc_rate_add)
         disc_rate.check()
 
@@ -97,7 +97,7 @@ def test_append_different_append(self):
         disc_rate_add.tag.description = 'descr2'
         disc_rate_add.years = np.array([2000, 2001, 2003])
         disc_rate_add.rates = np.array([0.11, 0.22, 0.33])
-        
+
         disc_rate.append(disc_rate_add)
         disc_rate.check()
 
@@ -119,9 +119,62 @@ def test_read_two_pass(self):
         self.assertEqual(disc_rate.tag.description, 'desc1 + desc2')
         self.assertEqual(disc_rate.years.size, 51)
 
+class TestSelect(unittest.TestCase):
+    """Test select method """
+    def test_select_pass(self):
+        """Test select right time range."""
+        disc_rate = DiscRates()
+        disc_rate.tag.file_name = 'file1.txt'
+        disc_rate.tag.description = 'descr1'
+        disc_rate.years = np.arange(2000, 2050)
+        disc_rate.rates = np.arange(disc_rate.years.size)
+
+        year_range = np.arange(2010, 2020)
+        sel_disc = disc_rate.select(year_range)
+
+        self.assertTrue(np.array_equal(sel_disc.years, year_range))
+        self.assertTrue(np.array_equal(sel_disc.rates, disc_rate.rates[10:20]))
+
+    def test_select_wrong_pass(self):
+        """Test select wrong time range."""
+        disc_rate = DiscRates()
+        disc_rate.tag.file_name = 'file1.txt'
+        disc_rate.tag.description = 'descr1'
+        disc_rate.years = np.arange(2000, 2050)
+        disc_rate.rates = np.arange(disc_rate.years.size)
+
+        year_range = np.arange(2050, 2060)
+        self.assertEqual(None, disc_rate.select(year_range))
+
+class TestNetPresValue(unittest.TestCase):
+    """Test select method """
+    def test_net_present_value_pass(self):
+        """Test net_present_value right time range."""
+        disc_rate = DiscRates()
+        disc_rate.tag.file_name = 'file1.txt'
+        disc_rate.tag.description = 'descr1'
+        disc_rate.years = np.arange(2000, 2050)
+        disc_rate.rates = np.ones(disc_rate.years.size)*0.02
+
+        val_years = np.ones(23)*6.512201157564418e9
+        res = disc_rate.net_present_value(2018, 2040, val_years)
+        self.assertEqual(res, 1.215049630691397e+11)
+
+    def test_net_present_value_wrong_pass(self):
+        """Test net_present_value wrong time range."""
+        disc_rate = DiscRates()
+        disc_rate.tag.file_name = 'file1.txt'
+        disc_rate.tag.description = 'descr1'
+        disc_rate.years = np.arange(2000, 2050)
+        disc_rate.rates = np.arange(disc_rate.years.size)
+        val_years = np.ones(11)*6.512201157564418e9
+        self.assertEqual(None, disc_rate.net_present_value(2050, 2060, val_years))
+
 # Execute Tests
 TESTS = unittest.TestLoader().loadTestsFromTestCase(TestChecker)
 TESTS.addTests(unittest.TestLoader().loadTestsFromTestCase(TestAppend))
 TESTS.addTests(unittest.TestLoader().loadTestsFromTestCase(TestConstructor))
 TESTS.addTests(unittest.TestLoader().loadTestsFromTestCase(TestReadParallel))
+TESTS.addTests(unittest.TestLoader().loadTestsFromTestCase(TestSelect))
+TESTS.addTests(unittest.TestLoader().loadTestsFromTestCase(TestNetPresValue))
 unittest.TextTestRunner(verbosity=2).run(TESTS)