Merge branch 'master' into fixI

TODO

@@ -148,6 +148,7 @@ causality since both parts lumped together.
 
 39. Avoid pole-zero cancellation for a transfer function derived from a differential or difference equation.
 
+40. Defer evaluation of twoports.
 
 Testing
 =======
@@ -178,22 +179,7 @@ Documentation
 Additional features
 ===================
 
-1. Handle mechanical and acoustical components.  Perhaps use lower case for
-mechanical/acoustical.  For example,
-
-   Force      f  (N)
-   Mass       m  (kg)
-   Spring     k  (N/m)
-   Damper     r  (kg/s)
-   Velocity   u  (m/s)
-
-   Could support both electro-mechnical analogues?  cct.electrical_analogue(1)?
-   m -> L, C
-   k -> C, L
-   f -> I, V
-   u -> V, I
-
-2. Expand two-ports, xtals, opamps, etc.  cct = cct.expand() Perhaps
+1. Expand two-ports, xtals, opamps, etc.  cct = cct.expand() Perhaps
 have arg to expand to select components and/or types of component to
 expand?
 

doc/examples/netlists/tf2-1.py

@@ -0,0 +1,5 @@
+from lcapy import Circuit
+
+a = Circuit('tf2.sch')
+
+H1 = a.transfer('V1', 'R3')

doc/examples/netlists/tf2-2.py

@@ -0,0 +1,5 @@
+from lcapy import Circuit
+
+a = Circuit('tf2.sch')
+
+H2 = a.transfer('V2', 'R3')

doc/examples/netlists/tf2.sch

@@ -0,0 +1,10 @@
+R1 3 1; down
+W1 3 4; right
+R2 4 5; down
+W2 2 6; right
+W3 4 8; right
+R3 8 9; down=2
+W4 6 9; right
+V2 5 6 ac; down
+V1 1 2 ac; down
+; draw_nodes=connections, label_nodes=none, style=american, voltage_dir=RP, label_style=value

doc/examples/schematics/frankenstein.sch

@@ -0,0 +1,6 @@
+R 1 2; right
+L 2 3; right
+I 3 4; right
+V 4 5; right
+; label_nodes=false, draw_nodes=connections, resistor_style=european
+; inductor_style=american, voltage_source_style=american, current_source_style=european

doc/examples/schematics/inductors.sch

@@ -4,4 +4,6 @@ L3 3 4; right, kind=tunable, l=tunable
 L4 4 5; right, kind=sensor, l=sensor
 L5 5 6; right, kind=choke, l=choke
 L6 6 7; right, kind=twolineschoke, l=twolineschoke
+L7 7 8; right, kind=american, l=american
+L8 8 9; right, kind=european, l=european
 ; label_nodes=false, draw_nodes=connections

doc/examples/schematics/label_value_style_eng.sch

@@ -0,0 +1,5 @@
+R1 1 2 3.1; right
+R2 2 3 3.1e6; right
+R3 3 4 3.141e3; right
+C1 4 5 3.14e-9; right
+; label_value_style=eng, label_style=value, label_nodes=false, draw_nodes=connections

doc/examples/schematics/label_value_style_sci.sch

@@ -0,0 +1,5 @@
+R1 1 2 3.1; right
+R2 2 3 3.1e6; right
+R3 3 4 3.141e3; right
+C1 4 5 3.14e-9; right
+; label_value_style=sci, label_style=value, label_nodes=false, draw_nodes=connections

doc/examples/schematics/label_value_style_spice.sch

@@ -0,0 +1,5 @@
+R1 1 2 3.1; right
+R2 2 3 3.1e6; right
+R3 3 4 3.141e3; right
+C1 4 5 3.14e-9; right
+; label_value_style=spice, label_style=value, label_nodes=false, draw_nodes=connections

doc/examples/schematics/lpf1-buffer-loaded3.sch

@@ -8,7 +8,7 @@ W 2 2_2; right
 E1 3 0_3 2 0 A; down, l=A V_{in}
 Rout 3 4; right=1.5
 RL 4 0_4; down, v=V_o
-W 0_2 0_3; size=1.2
+W 0_2 0_3; size=1.3
 W 0_3 0_4
 P1 4 0_4; down
-; style=european
+; style=european

doc/examples/tutorials/opamps/opamp-piezo-amplifier2-frequency-response1.py

@@ -3,7 +3,7 @@
 
 a = Circuit('opamp-piezo-amplifier1.sch')
 
-H = a.transfer('Cs', 'Po')(f).limit('A', oo)
+H = a.kill().transfer('Cs', 'Po')(f).limit('A', oo)
 
 defs1 = {'R1':100, 'R2':900, 'Cs':1e-9, 'Rs':100e6, 'C':100e-6, 'Vn':2e-9, 'Inp':5e-15, 'Inn':5e-15}
 defs2 = {'R1':100, 'R2':900, 'Cs':1e-9, 'Rs':100e6, 'C':10e-6, 'Vn':2e-9, 'Inp':5e-15, 'Inn':5e-15}
@@ -22,6 +22,3 @@
 
 from matplotlib.pyplot import savefig
 savefig(__file__.replace('.py', '.png'), bbox_inches='tight')
-
-
-

doc/netlists.rst

@@ -54,15 +54,17 @@ A Component object is obtained from a Circuit object using member notation, for
 Component specification
 -----------------------
 
-Each line in a netlist describes a single component, with the
-general form::
+Each line in a netlist describes a single component, except for lines
+starting with `#`.  The latter are treated as comments.
+
+The general form of a netlist component definition is::
 
     `component-name positive-node negative-node arg1 [arg2 etc.] [; attributes]
 
-If no args are specified then the component value is assigned a
+If no arguments are specified then the component value is assigned a
 symbolic name specified by `component-name`.
 
-Lines starting with `#` are treated as comments.
+
 
 The attributes are primarily for controlling the appearance of the schematic.  The attribute `nosim` is used to ignore the component for electrical analysis.
 
@@ -525,15 +527,17 @@ Circuit methods
   nodes `Np` and `Nm` and `impedance(cpt)` returns the driving-point
   impedance between the nodes of the specified component
 
-- `in_parallel(component_name)` Returns a set of component names that are connected in parallel with `component_name`
+- `in_parallel(component_name)` Returns a set of component names that are connected in parallel with `component_name` (see also `across_nodes()` and `in_series()`)
 
-- `in_series(component_name)` Returns a set of component names that are connected in series with `component_name`
+- `in_series(component_name)` Returns a set of component names that are connected in series with `component_name` (see also `in_parallel()`)
 
 - `kill()` Kills specified independent sources (voltage sources
   become short-circuits and current sources become open-circuits)
 
 - `kill_except()` Kills all but the specified independent sources
 
+- `prune(component_name)` Returns a copy of the netlist with the component specified by `component_name` removed
+
 - `noise_model()` Replaces resistors with a series combination of a
   resistor and a noise voltage source.  For example,
 

doc/schematics.rst

@@ -436,7 +436,7 @@ Inductors and chokes
 .. literalinclude:: examples/schematics/inductors.sch
 
 .. image:: examples/schematics/inductors.png
-   :width: 10cm
+   :width: 15cm
 
 
 .. _chips:
@@ -1256,6 +1256,20 @@ Alternatively the style can specified by a schematic option.  For example:
    :width: 10.5cm
 
 
+The style of inductors, resistors, current sources, and voltage
+sources can be overridden with `inductor_style`, `resistor_style`,
+`current_source_style`, and `voltage_source_style`.  These can be
+`american` or `european`.  In addition, the inductor style can be
+`cute`.
+
+Here's an example (I wonder who would do this?):
+
+.. literalinclude:: examples/schematics/frankenstein.sch
+
+.. image:: examples/schematics/frankenstein.png
+   :width: 8cm
+
+
 Colors
 ------
 
@@ -1497,6 +1511,17 @@ There are several label formatting styles controlled by the
 The component name and value can be overridden with the 'l' attribute.
 
 
+.. _label_value_style:
+
+Label value style
+-----------------
+
+Label values are formatted according to the `label_value_style`
+attribute.  The default is `eng3` which uses an engineering format
+with a maximum of three digits.  Other formats include 'SPICE' and
+`sci` (scientific).
+
+
 .. _label_placement:
 
 Label placement

lcapy/expr.py

@@ -121,7 +121,7 @@ def latex_with_units(self, eng_format=False, show_units=True,
         """Make LaTeX string with optional units.   Units are only
         shown for numerical values."""
 
-        from .engformatter import EngFormatter
+        from .valueformatter import value_formatter
 
         expr = self
 
@@ -138,7 +138,7 @@ def latex_with_units(self, eng_format=False, show_units=True,
         value = expr.sympy
 
         if evalf and value.is_number and eng_format:
-            return EngFormatter(num_digits=num_digits).latex(value, units)
+            return value_formatter().latex(value, units)
 
         s = latex(value, **kwargs)
         if show_units and units != '':
@@ -3245,7 +3245,7 @@ def canonical(self, factor_const=False):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.canonical(factor_const),
                               **self.assumptions)
 
@@ -3258,7 +3258,7 @@ def general(self):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.general(), **self.assumptions)
 
     def partfrac(self, combine_conjugates=False, pairs=False, damping=None,
@@ -3287,7 +3287,7 @@ def partfrac(self, combine_conjugates=False, pairs=False, damping=None,
         try:
             ratfun = self._ratfun
             if ratfun is None:
-                return self.copy()
+                return self
             return self.__class__(ratfun.partfrac(pairs, damping, method),
                                   **self.assumptions)
         except ValueError:
@@ -3319,7 +3319,7 @@ def recippartfrac(self, combine_conjugates=False, pairs=False,
         pairs = pairs or combine_conjugates
 
         if self._ratfun is None:
-            return self.copy()
+            return self
 
         tmpsym = miscsymbol('qtmp')
 
@@ -3345,7 +3345,7 @@ def standard(self):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.standard(), **self.assumptions)
 
     def mixedfrac(self):
@@ -3363,7 +3363,7 @@ def timeconst(self):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.timeconst(), **self.assumptions)
 
     def timeconst_terms(self):
@@ -3393,7 +3393,7 @@ def ZPK(self, pairs=False, combine_conjugates=False):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.ZPK(combine_conjugates or pairs),
                               **self.assumptions)
 
@@ -3413,7 +3413,7 @@ def factored(self, pairs=False):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.ZPK(pairs), **self.assumptions)
 
     def expandcanonical(self):
@@ -3426,7 +3426,7 @@ def expandcanonical(self):
 
         ratfun = self._ratfun
         if ratfun is None:
-            return self.copy()
+            return self
         return self.__class__(ratfun.expandcanonical(), **self.assumptions)
 
     def expand_functions(self):

lcapy/labelmaker.py

@@ -1,6 +1,7 @@
 from .expr import Expr
 from .latex import latex_format_label
-from .engformatter import EngFormatter
+from .valueformatter import value_formatter
+from .valueparser import value_parser
 import sympy as sym
 
 
@@ -10,9 +11,9 @@ def _format_expr(self, expr):
 
         return Expr(expr, cache=False).latex_math()
 
-    def _format_value_units(self, value, units):
+    def _format_value_units(self, value, units, style):
 
-        return EngFormatter().latex_math(value, units)
+        return value_formatter(style=style).latex_math(value, units)
 
     def _format_name(self, cpt_type, cpt_id):
 
@@ -30,7 +31,7 @@ def _format_name(self, cpt_type, cpt_id):
             name = name + '_{%s}' % subscript
         return latex_format_label('$' + name + '$')
 
-    def make(self, cpt, label_ports=False):
+    def make(self, cpt, label_ports=False, style='SI'):
 
         # There are two possible labels for a component:
         # 1. Component name, e.g., R1
@@ -55,7 +56,8 @@ def make(self, cpt, label_ports=False):
             units_map = {'V': 'V', 'I': 'A', 'R': '$\Omega$',
                          'C': 'F', 'L': 'H'}
 
-            expr = cpt.args[0]
+            expr = value_parser(cpt.args[0])
+
             if cpt.classname in ('Vstep', 'Istep'):
                 expr = '(%s) * Heaviside(t)' % expr
                 value_label = self._format_expr(expr)
@@ -80,7 +82,7 @@ def make(self, cpt, label_ports=False):
                     value = float(sym.Rational(expr))
                     if cpt.type in units_map:
                         value_label = self._format_value_units(
-                            value, units_map[cpt.type])
+                            value, units_map[cpt.type], style)
                     else:
                         value_label = self._format_expr(expr)
 

lcapy/matrix.py

@@ -157,6 +157,12 @@ def f(x):
 
         return self.applyfunc(f)
 
+    def limit(self, var, value, dir='+'):
+
+        def f(x): return expr(x).limit(var, value, dir)
+
+        return self.applyfunc(f)
+
     def next_timestep(self):
 
         def f(x): return expr(x).next_timestep()