Implement brentq for Reynolds and allow Newton to break after first residual calculation if value is 0

Author: fwitte

src/tespy/components/piping/pipe.py

@@ -294,7 +294,7 @@ class Pipe(SimpleHeatExchanger):
     ... )
     >>> nw.solve("design")
     >>> round(pi.Q.val, 2)
-    -2434.12
+    -2434.13
     """
 
     def _preprocess(self, row_idx):

src/tespy/tools/fluid_properties/helpers.py

@@ -15,6 +15,7 @@
 
 import CoolProp.CoolProp as CP
 import numpy as np
+from scipy.optimize import brentq
 
 from tespy.tools.global_vars import ERR
 from tespy.tools.helpers import central_difference
@@ -219,40 +220,18 @@ def darcy_friction_factor(re, ks, d):
             elif re < 1e6:
                 return hanakov(re)
             else:
-                l0 = 0.02
-                function_kwargs = {
-                    "function": prandtl_karman,
-                    "parameter": "darcy_friction_factor",
-                    "reynolds": re
-
-                }
-                return newton_with_kwargs(
-                    prandtl_karman_derivative,
-                    0,
-                    val0=l0,
-                    valmin=0.00001,
-                    valmax=0.2,
-                    **function_kwargs
-                )
+                try:
+                    return brentq(lambda lam: prandtl_karman(re, lam), 0.00001, 0.2)
+                except ValueError:
+                    a, b = 0.00001, 0.2
+                    return a if abs(prandtl_karman(re, a)) <= abs(prandtl_karman(re, b)) else b
 
         else:
-            l0 = 0.002
-            function_kwargs = {
-                "function": colebrook,
-                "parameter": "darcy_friction_factor",
-                "reynolds": re,
-                "ks": ks,
-                "diameter": d,
-                "delta": 0.001
-            }
-            return newton_with_kwargs(
-                central_difference,
-                0,
-                val0=l0,
-                valmin=0.0001,
-                valmax=0.2,
-                **function_kwargs
-            )
+            try:
+                return brentq(lambda lam: colebrook(re, ks, d, lam), 0.0001, 0.2)
+            except ValueError:
+                a, b = 0.0001, 0.2
+                return a if abs(colebrook(re, ks, d, a)) <= abs(colebrook(re, ks, d, b)) else b
 
 
 def blasius(re):

src/tespy/tools/helpers.py

@@ -573,11 +573,22 @@ def newton_with_kwargs(
         tol_mode = "abs"
 
     while expr:
-        # calculate function residual and new value
         function_kwargs[parameter] = x
         residual = target_value - function(**function_kwargs)
+
+        if residual == 0:
+            break
+
+        if tol_mode == 'abs':
+            expr = abs(residual) >= tol_abs
+        elif tol_mode == 'rel':
+            expr = abs(residual / target_value) >= tol_rel
+
         x += residual / derivative(**function_kwargs) * relax
 
+        if not expr:
+            break
+
         # check for value ranges
         if x < valmin:
             x = valmin
@@ -599,12 +610,7 @@ def newton_with_kwargs(
                 'iterations.'
             )
             logger.debug(msg)
-
             break
-        if tol_mode == 'abs':
-            expr = abs(residual) >= tol_abs
-        elif tol_mode == 'rel':
-            expr = abs(residual / target_value) >= tol_rel
 
     return x