Add default for xferfcn.floating_point_format

henklaak · henklaak · commit 8d7ac56eb7a5 · 2023-02-25T13:48:32.000+01:00
diff --git a/control/tests/xferfcn_test.py b/control/tests/xferfcn_test.py
@@ -10,7 +10,7 @@
 import control as ct
 from control import StateSpace, TransferFunction, rss, evalfr
 from control import ss, ss2tf, tf, tf2ss, zpk
-from control import isctime, isdtime, sample_system, defaults
+from control import isctime, isdtime, sample_system, defaults, reset_defaults
 from control.statesp import _convert_to_statespace
 from control.xferfcn import _convert_to_transfer_function
 from control.tests.conftest import slycotonly, matrixfilter
@@ -970,6 +970,33 @@ def test_printing_zpk(self, zeros, poles, gain, output):
         res = str(G)
         assert res == output
 
+    @pytest.mark.parametrize(
+        "zeros, poles, gain, format, output",
+        [([1], [1 + 1j, 1 - 1j], 1, ".2f",
+          '\n'
+          '                1.00\n'
+          '-------------------------------------\n'
+          '(s + (1.00-1.41j)) (s + (1.00+1.41j))\n'),
+         ([1], [1 + 1j, 1 - 1j], 1, ".3f",
+          '\n'
+           '                  1.000\n'
+           '-----------------------------------------\n'
+           '(s + (1.000-1.414j)) (s + (1.000+1.414j))\n'),
+         ([1], [1 + 1j, 1 - 1j], 1, ".6g",
+          '\n'
+          '                  1\n'
+          '-------------------------------------\n'
+          '(s + (1-1.41421j)) (s + (1+1.41421j))\n')
+         ])
+    def test_printing_zpk_format(self, zeros, poles, gain, format, output):
+        """Test _tf_polynomial_to_string for constant systems"""
+        defaults['xferfcn.floating_point_format'] = format
+        G = tf([1], [1,2,3], display_format='zpk')
+        res = str(G)
+        reset_defaults()
+
+        assert res == output
+
     @pytest.mark.parametrize(
         "num, den, output",
         [([[[11], [21]], [[12], [22]]],
diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -71,8 +71,12 @@
 # Define module default parameter values
 _xferfcn_defaults = {
     'xferfcn.display_format': 'poly',
+    'xferfcn.floating_point_format': '.4g'
 }
 
+def _float2str(value):
+    formatter = "{:" + config.defaults.get('xferfcn.floating_point_format', ':.4g') + "}"
+    return formatter.format(value)
 
 class TransferFunction(LTI):
     """TransferFunction(num, den[, dt])
@@ -1313,7 +1317,7 @@ def _tf_polynomial_to_string(coeffs, var='s'):
     N = len(coeffs) - 1
 
     for k in range(len(coeffs)):
-        coefstr = '%.4g' % abs(coeffs[k])
+        coefstr = _float2str(abs(coeffs[k]))
         power = (N - k)
         if power == 0:
             if coefstr != '0':
@@ -1355,7 +1359,7 @@ def _tf_factorized_polynomial_to_string(roots, gain=1, var='s'):
     """Convert a factorized polynomial to a string"""
 
     if roots.size == 0:
-        return f"{gain:.4g}"
+        return _float2str(gain)
 
     factors = []
     for root in sorted(roots, reverse=True):
@@ -1364,29 +1368,29 @@ def _tf_factorized_polynomial_to_string(roots, gain=1, var='s'):
                 factor = f"{var}"
                 factors.append(factor)
             elif root > 0:
-                factor = f"{var} - {np.abs(root):.4g}"
+                factor = f"{var} - {_float2str(np.abs(root))}"
                 factors.append(factor)
             else:
-                factor = f"{var} + {np.abs(root):.4g}"
+                factor = f"{var} + {_float2str(np.abs(root))}"
                 factors.append(factor)
         elif np.isreal(root * 1j):
             if root.imag > 0:
-                factor = f"{var} - {np.abs(root):.4g}j"
+                factor = f"{var} - {_float2str(np.abs(root))}j"
                 factors.append(factor)
             else:
-                factor = f"{var} + {np.abs(root):.4g}j"
+                factor = f"{var} + {_float2str(np.abs(root))}j"
                 factors.append(factor)
         else:
             if root.real > 0:
-                factor = f"{var} - ({root:.4g})"
+                factor = f"{var} - ({_float2str(root)})"
                 factors.append(factor)
             else:
-                factor = f"{var} + ({-root:.4g})"
+                factor = f"{var} + ({_float2str(-root)})"
                 factors.append(factor)
 
     multiplier = ''
     if round(gain, 4) != 1.0:
-        multiplier = f"{gain:.4g} "
+        multiplier = _float2str(gain) + " "
 
     if len(factors) > 1 or multiplier:
         factors = [f"({factor})" for factor in factors]
