ahkab · itdaniher · Dec 30, 2014 · Jan 6, 2015 · Apr 15, 2015 · Apr 19, 2015
diff --git a/README.md b/README.md
@@ -5,137 +5,51 @@
 
 The code should be easy to read and modify, the main language is Python -- 2 or 3 -- and it is platform-independent.
 
-News!
------
+## Welcome to the PYPY branch of `ahkab`!
 
--   Ahkab v0.16 was released on May 3 2015, including new features, many bugfixes and improved documentation. It is recommended to upgrade. Check out [the release notes](https://github.com/ahkab/ahkab/releases/tag/v0.16) for more!
--   The whole codebase has been going through a (yet incomplete) refactoring and documenting effort. The [new documentation is available on RTD](http://ahkab.readthedocs.org/en/latest/).
+* We try to run always against the latest [pypy](http://pypy.org/).
+* Right now, most efforts are geared towards the Python 2 implementation, but that's just temporary.
 
-My resources are limited these days, so the much-needed work is proceeding slowly, albeit hopefully steadily. If you are interested and you would like to contribute to refactoring or documenting a particular feature, it would be very welcome.
+All which is not strictly necessary is disabled in this experimental branch.
 
-[![Build Status](https://travis-ci.org/ahkab/ahkab.png?branch=master)](https://travis-ci.org/ahkab/ahkab) [![Coverage Status](https://coveralls.io/repos/ahkab/ahkab/badge.png?branch=master)](https://coveralls.io/r/ahkab/ahkab?branch=master) [![PyPi version](http://img.shields.io/badge/version-0.16-brightgreen.png)](https://pypi.python.org/pypi/ahkab/) [![GPLv2 license](http://img.shields.io/badge/license-GPL%20v2-brightgreen.png)](https://raw.githubusercontent.com/ahkab/ahkab/master/LICENSE)
-[![DOI](https://zenodo.org/badge/doi/10.5281/zenodo.17404.svg)](http://dx.doi.org/10.5281/zenodo.17404)
+## Performance
 
-Supported simulations:
-----------------------
+Although numeric code does not really work for now with Pypy (we need `scipy`!), symbolic calculations are performed
+very quickly on this alternative Python implementation.
 
--   Numeric:
-    -   **Operating point**, with guess computation to speed up the solution. See example: [Downscaling current mirror](https://ahkab.readthedocs.org/en/latest/examples/OP_simulation.html)
-    -   **DC sweep**
-    -   **Transient analysis**, available differentiation formulas: implicit Euler, trapezoidal, gear orders from 2 to 5. See for example the [simulation of a Colpitts Oscillator](https://ahkab.readthedocs.org/en/latest/examples/Transient-Example.html).
-    -   **AC analysis**
-    -   **PZ** analysis
-    -   **Periodic steady state analysis** of non-autonomous circuits, *time* *domain* shooting and brute-force algorithms.
--   Symbolic:
-    -   **Small signal analysis**, AC or DC, with extraction of transfer functions, DC gain, poles and zeros. Various [symbolic analysis examples on this page](https://ahkab.readthedocs.org/en/latest/examples/Symbolic-simulation.html).
+Take a look at PYPY running 5+ times faster than CPython with no speed optimization on our side:
 
-The results are saved to disk, plotted or printed to stdout and can be read/processed by the most common tools (eg. [Octave](http://www.gnu.org/software/octave/), [gnuplot](http://www.gnuplot.info/), [Matlab](http://www.mathworks.com/products/matlab/), [gwave](http://www.telltronics.org/software/gwave/) and others)
 
-Install
--------
-
-The program requires:
-
--   the Python interpreter version 2 or 3 (at least v.2.6 for Python2, v.3.3 for Python3),
--   numpy>=1.7.0, scipy>=0.14.0, sympy>=0.7.6 and tabulate>=0.7.3.
-
-Matplotlib is strongly recommended and no plotting will work without.
-
-If you need more information about the dependencies, check the [Install notes](https://ahkab.readthedocs.org/en/latest/help/Install-Notes.html).
-
-Usage
------
-
-### 1. `ahkab` can be run as a Python library
-
-<img src="https://rawgithub.com/ahkab/ahkab/master/doc/images/readme_example/pbf.svg" alt="Example schematic: a 5th order 1kHz band-pass Butterworth filter"/>
-
-``` {.sourceCode .python}
-from ahkab import new_ac, run
-from ahkab.circuit import Circuit
-from ahkab.plotting import plot_results # calls matplotlib for you
-import numpy as np
-
-# Define the circuit
-cir = Circuit('Butterworth 1kHz band-pass filter')
-cir.add_vsource('V1', 'n1', cir.gnd, dc_value=0., ac_value=1.)
-cir.add_resistor('R1', 'n1', 'n2', 50.)
-cir.add_inductor('L1', 'n2', 'n3', 0.245894)
-cir.add_capacitor('C1', 'n3', 'n4', 1.03013e-07)
-cir.add_inductor('L2', 'n4', cir.gnd, 9.83652e-05)
-cir.add_capacitor('C2', 'n4', cir.gnd, 0.000257513)
-cir.add_inductor('L3', 'n4', 'n5', 0.795775)
-cir.add_capacitor('C3', 'n5', 'n6', 3.1831e-08)
-cir.add_inductor('L4', 'n6', cir.gnd, 9.83652e-05)
-cir.add_capacitor('C4', 'n6', cir.gnd, 0.000257513)
-cir.add_capacitor('C5', 'n7', 'n8', 1.03013e-07)
-cir.add_inductor('L5', 'n6', 'n7', 0.245894)
-cir.add_resistor('R2', 'n8', cir.gnd, 50.)
-
-# Define the analysis
-ac1 = new_ac(2.*np.pi*.97e3, 2.*np.pi*1.03e3, 1e2, x0=None)
-
-# run it
-res = run(cir, ac1)
-
-# plot the results
-plot_results('5th order 1kHz Butterworth filter', [('|Vn8|',"")], res['ac'],
-             outfilename='bpf_transfer_fn.png')
 ```
-
-<img src="https://rawgithub.com/ahkab/ahkab/master/doc/images/readme_example/bpf_results.svg" alt="Example: AC simulation results"/>
-
-#### 2. `ahkab` can be run from the command line with a netlist file
-
-The syntax is:
-
-    `$ python ahkab -o graph.dat <netlist file>`
-
-See `ahkab --help` for command line switches, [also online on the documentation pages.](http://ahkab.readthedocs.org/en/latest/help/Command-Line-Help.html)
-
-### Documentation
-
-The [documentation is available on RTD](http://ahkab.readthedocs.org/en/latest/).
-
-There, you can find a [documentation](http://ahkab.readthedocs.org/en/latest/ahkab.html) and [examples](http://ahkab.readthedocs.org/en/latest/examples/Python_API.html) regarding how to simulate from a Python script.
-
-Refer to the [netlist syntax page](http://ahkab.readthedocs.org/en/latest/help/Netlist-Syntax.html) if you prefer to write netlist files that describe the circuit.
-
-Experience with running SPICE or related commercial simulators can be very useful: this is not for the faint of heart.
-
-### Development model
-
--   The development happens on the [github repository](https://github.com/ahkab/ahkab),
--   Mostly on the master branch, with feature branch being created only for special purposes or non-trivial features.
--   Snapshots are released on a (hopefully) regular basis and are available on the [Releases pages, complete with changelog](https://github.com/ahkab/ahkab/releases) and on [PYPI](https://pypi.python.org/pypi/ahkab/)
-
-Patches and pull requests are welcome!
-
-### How this project was born
-
-This project was born when I was an enthusistic undergrad, apparently with plenty of free time, attending "Simulazione Circuitale" (*Circuit Simulation*) taught by [Prof. A. Brambilla](http://brambilla.dei.polimi.it/) back in Italy at the Polytechnic University of Milan.
-
-I am grateful to prof. Brambilla for teaching one of the most interesting courses of my university years. -GV
-
-### Bugs and patches
-
-Does it work? Bugs? Do you have patches? Did you run some noteworthy simulation? Let me know! Feedback is very welcome, my [email address](http://tinymailto.com/5310) is available after a captcha.
-
-### Support the development with a donation
-
-If you wish to support the development of `ahkab`, ***please donate to cancer research:***
-
--   [Association for International Cancer Research (eng)](http://www.aicr.org.uk/donate.aspx),
-
-or
-
--   [Fond. IRCCS Istituto Nazionale dei Tumori (it)](http://www.istitutotumori.mi.it/modules.php?name=Content&pa=showpage&pid=24).
-
-### Credits
-
-**Authors:** [Giuseppe Venturini](https://github.com/ggventurini), with contributions from [Ian Daniher](https://github.com/itdaniher) and [Rob Crowther](https://github.com/weilawei).
-
-**Code:** the module `py3compat.py` is (c) 2013 - the Jinja team.
-
-**Dependencies:** many thanks to the authors of `numpy`, `scipy`, `sympy`, ``matplotlib`` and ``tabulate``!
-
+          Runtime [s]
+          0.000     1.295     2.590     3.885     5.180     6.475     7.770     9.065     10.360     
+          |         |         |         |         |         |         |         |         |         
+ Nodes    +--------------------------------------------------------------------------------->
+          |
+    2.000 +o
+          |=*
+          |
+    4.000 +o
+          |==*
+          |
+    6.000 +o
+          |===*
+          |
+    8.000 +----o
+          |=====*
+          |
+   10.000 +--------------------o
+          |=======*
+          |
+   12.000 +-------------------------------------------------------------------------------o
+          |============*
+          |
+          +--------------------------------------------------------------------------------->
+          |         |         |         |         |         |         |         |         |         
+          0.000     1.295     2.590     3.885     5.180     6.475     7.770     9.065     10.360     
+          Runtime [s]
+
+    LEGEND:
+    --* Ahkab 0.16-pypy, running on CPython, R2R ladder DAC
+    ==o Ahkab 0.16-pypy, running on Pypy2, R2R ladder DAC
+```
diff --git a/ahkab/ahkab.py b/ahkab/ahkab.py
@@ -136,8 +136,17 @@
 from optparse import OptionParser
 
 import numpy as np
-import scipy as sp
+
+# There's no scipy on pypy
+try:
+    import scipy as sp
+    scipy_available = True
+except ImportError:
+    scipy_available = False
+
 import sympy
+
+# no matplotlib -> no plotting
 import tabulate
 try:
     import matplotlib
@@ -146,12 +155,14 @@
     plotting_available = False
 
 # analyses
-from . import dc_analysis
-from . import transient
-from . import ac
-from . import pss
+if scipy_available:
+    from . import dc_analysis
+    from . import transient
+    from . import ac
+    from . import pss
+    from . import pz
+
 from . import symbolic
-from . import pz
 
 # parser
 from . import netlist_parser
@@ -289,7 +300,7 @@ def new_dc(start, stop, points, source, sweep_type='LINEAR', guess=True, x0=None
         'verbose': verbose}
 
 
-def new_tran(tstart, tstop, tstep, x0='op', method=transient.TRAP,
+def new_tran(tstart, tstop, tstep, x0='op', method='TRAP',
         use_step_control=True, outfile=None, verbose=0):
     """Assembles a TRAN analysis and returns the analysis object.
 
@@ -782,10 +793,17 @@ def process_postproc(postproc_list, title, results, outfilename):
         plotting.show_plots()
     return None
 
-analysis = {'op': dc_analysis.op_analysis, 'dc': dc_analysis.dc_analysis,
-            'tran': transient.transient_analysis, 'ac': ac.ac_analysis,
-            'pss': pss.pss_analysis, 'symbolic': symbolic.symbolic_analysis,
-            'temp': set_temperature, 'pz':pz.calculate_singularities}
+if scipy_available:
+    analysis = {'op': dc_analysis.op_analysis,
+                'dc': dc_analysis.dc_analysis,
+                'tran': transient.transient_analysis,
+                'ac': ac.ac_analysis,
+                'pss': pss.pss_analysis,
+                'symbolic': symbolic.symbolic_analysis,
+                'temp':set_temperature,
+                'pz':pz.calculate_singularities}
+else:
+    analysis = {'symbolic': symbolic.symbolic_analysis}
 
 
 def main(filename, outfile="stdout", verbose=3):
@@ -825,7 +843,11 @@ def main(filename, outfile="stdout", verbose=3):
     printing.print_info_line(
         ("  Python %s" % (sys.version.split('\n')[0],), 6), verbose)
     printing.print_info_line(("  Numpy %s" % (np.__version__), 6), verbose)
-    printing.print_info_line(("  Scipy %s" % (sp.__version__), 6), verbose)
+    if scipy_available:
+        printing.print_info_line(("  Scipy %s" % (sp.__version__), 6), verbose)
+    else:
+        printing.print_info_line(
+                ("  Scipy not found: functionality will be reduced.", 6), verbose)
     printing.print_info_line(("  Sympy %s" % (sympy.__version__), 6), verbose)
     printing.print_info_line(("  Tabulate %s" % (tabulate.__version__), 6), verbose)
     if plotting_available:
@@ -837,7 +859,7 @@ def main(filename, outfile="stdout", verbose=3):
                                  (matplotlib.matplotlib_fname()), 6), verbose)
     else:
         printing.print_info_line(
-            ("  Matplotlib not found.", 6), verbose)
+            ("  Matplotlib not found, plotting disabled.", 6), verbose)
 
 
     read_netlist_from_stdin = (filename is None or filename == "-")

diff --git a/ahkab/dc_analysis.py b/ahkab/dc_analysis.py
@@ -45,8 +45,13 @@
 
 import numpy as np
 import numpy.linalg
-import scipy.sparse
-import scipy.sparse.linalg
+
+try:
+    import scipy.sparse
+    import scipy.sparse.linalg
+except ImportError:
+    pass
+    # pypy run! no numeric code will run!
 
 from . import devices
 from . import diode

diff --git a/ahkab/diode.py b/ahkab/diode.py
@@ -34,9 +34,14 @@
                         division, print_function)
 
 import numpy as np
-import scipy, scipy.optimize
 
-from scipy.optimize import newton
+try:
+    import scipy, scipy.optimize
+    from scipy.optimize import newton
+except ImportError:
+    pass
+    # pypy run. If the user will try numeric stuff we'll fail
+    # ungracefully. After all, this is an experiment!
 
 from . import constants
 from . import printing

diff --git a/ahkab/ekv.py b/ahkab/ekv.py
@@ -74,10 +74,15 @@
 from __future__ import (unicode_literals, absolute_import,
                         division, print_function)
 
-import scipy, scipy.optimize
-import math
+try:
+    import scipy, scipy.optimize
+    from scipy.optimize import newton
+except ImportError:
+    pass
+    # pypy run
+    # no numerical stuff
 
-from scipy.optimize import newton
+import math
 
 from . import constants
 from . import options

diff --git a/ahkab/netlist_parser.py b/ahkab/netlist_parser.py
@@ -110,7 +110,14 @@
 import os
 
 from . import circuit
-from . import dc_analysis
+
+try:
+    from . import dc_analysis
+except ImportError:
+    #will fail on pypy
+    # no numeric simulations there
+    pass
+
 from . import devices
 from . import diode
 from . import mosq
@@ -122,12 +129,16 @@
 from . import options
 
 # analyses syntax
-from .dc_analysis import specs as dc_spec
-from .ac import specs as ac_spec
-from .transient import specs as tran_spec
-from .pss import specs as pss_spec
-from .pz import specs as pz_specs
+try:
+    from .dc_analysis import specs as dc_spec
+    from .ac import specs as ac_spec
+    from .transient import specs as tran_spec
+    from .pss import specs as pss_spec
+    from .pz import specs as pz_specs
+except ImportError:
+    dc_spec = ac_spec = tran_spec = pss_spec = pz_specs = {}
 from .symbolic import specs as symbolic_spec
+
 from .devices import time_fun_specs
 from .devices import sin, pulse, exp
 

diff --git a/ahkab/options.py b/ahkab/options.py
@@ -176,8 +176,9 @@
 plotting_display_figsize = (12.94, 8)
 #: Default size for plots saved to disk.
 plotting_save_figsize = (20, 10)
-# plotting_rcParams['font.family'] = 'Baskerville'
-plotting_rcParams['axes.labelsize'] = 11
-plotting_rcParams['xtick.labelsize'] = 11
-plotting_rcParams['ytick.labelsize'] = 11
-plotting_rcParams['legend.fontsize'] = 11
+if plotting_rcParams is not None:
+    # plotting_rcParams['font.family'] = 'Baskerville'
+    plotting_rcParams['axes.labelsize'] = 11
+    plotting_rcParams['xtick.labelsize'] = 11
+    plotting_rcParams['ytick.labelsize'] = 11
+    plotting_rcParams['legend.fontsize'] = 11
diff --git a/ahkab/testing.py b/ahkab/testing.py
@@ -386,7 +386,11 @@ def test():
 import numpy as np
 import sympy
 
-from scipy.interpolate import InterpolatedUnivariateSpline
+try:
+    from scipy.interpolate import InterpolatedUnivariateSpline
+except ImportError:
+    pass
+    # pypy run!
 
 from nose.tools import ok_, nottest
 from nose.plugins.skip import SkipTest