code wrap up and edfa model augmentation v2 (#30)

* JSON file based on Orange operator typical input
Signed-off-by: Jean-Luc Auge <jeanluc.auge@orange.com>

* update of the standalone edfa model

creation of a new amlifier2.py = v2
creation of a json parser build_oa_json.py
the parser takes OA.json as input and newOA.json as output
creation of a pytest verification module amplifier_pytest.py

Signed-off-by: Jean-Luc Auge <jeanluc.auge@orange.com>

* put the code together and transmission example script

-basic dijkstra propagation
-ase noise propagation based on amplifier model
-fake nli noise propagation
-integration of the amplifier model
-interpolation function in the edfa class
-code cleaning and units harmonization

Signed-off-by: Jean-Luc Auge <jeanluc.auge@orange.com>

* mv transmission_main_example and rm _main__

Signed-off-by: Jean-Luc Auge <jeanluc.auge@orange.com>

* 2nd edfa model and build_oa_json file

add a dual coil stages edfa model in case the nf polynomial fit is not known
add a build_oa_json file that convert the input files in
edfa_config.json file and pre-calculate the nf_model nf1, nf2 and
delta_p parameters
adding power violation check and input padding (below minimum gain) in the edfa model
class

Signed-off-by: Jean-Luc Auge <jeanluc.auge@orange.com>

examples/transmission_main_example.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env 
+"""
+@author: briantaylor
+@author: giladgoldfarb
+@author: jeanluc-auge
+
+Transmission setup example: 
+reads from network json (default = examples/edfa/edfa_example_network.json)
+propagates a 96 channels comb 
+"""
+from argparse import ArgumentParser
+from json import load
+from sys import exit
+from pathlib import Path
+from logging import getLogger, basicConfig, INFO, ERROR, DEBUG
+
+from matplotlib.pyplot import show, axis
+from networkx import (draw_networkx_nodes, draw_networkx_edges,
+                      draw_networkx_labels, dijkstra_path)
+
+from gnpy.core import network_from_json
+from gnpy.core.elements import Transceiver, Fiber, Edfa
+from gnpy.core.info import SpectralInformation, Channel, Power
+#from gnpy.core.algorithms import closed_paths
+
+logger = getLogger(__package__ or __file__)
+
+def format_si(spectral_infos):
+    return '\n'.join([
+        f'#{idx} Carrier(frequency={c.frequency},\n  power=Power(signal={c.power.signal}, nli={c.power.nli}, ase={c.power.ase}))'
+        for idx, si in sorted(set(spectral_infos))
+        for c in set(si.carriers)
+    ])
+
+logger = getLogger('gnpy.core')
+
+def main(args):
+    with open(args.filename) as f:
+        json_data = load(f)
+
+    network = network_from_json(json_data)
+    """jla put in comment
+    pos    = {n: (n.lng, n.lat) for n in network.nodes()}
+    labels_pos = {n: (long-.5, lat-.5) for n, (long, lat) in pos.items()}
+    size   = [20 if isinstance(n, Fiber) else 80 for n in network.nodes()]
+    color  = ['green' if isinstance(n, Transceiver) else 'red'
+              for n in network.nodes()]
+    labels = {n: n.location.city if isinstance(n, Transceiver) else ''
+              for n in network.nodes()}
+    """
+
+    spacing = 0.05 #THz
+    si = SpectralInformation() # !! SI units W, Hz
+    si = si.update(carriers=tuple(Channel(f+1, (191.3+spacing*(f+1))*1e12, 
+            32e9, 0.15, Power(1e-3, 0, 0)) for f in range(96)))
+
+    nodes = [n for n in network.nodes() if isinstance(n, Transceiver)]
+    source, sink = nodes[0], nodes[1]
+    results = dijkstra_path(network, source, sink)
+    print('dijkstra path:', results)
+
+    for ne in results:
+        si = ne(si)
+
+    print('total SNR comb in signal bandwidth', sink.snr(si))
+
+    #print(Rx_signal_power[0])
+    #p.array([c.power.signal+c.power.nli+c.power.ase for c in carriers]) 
+
+    """jla put in comment 
+    results = list(islice(closed_paths(network, source, sink, si), 3))
+    paths = [[n for _, n, _ in r] for r in results]
+    infos = {}
+    for idx, r in enumerate(results):
+        for in_si, node, out_si in r:
+            infos.setdefault(node, []).append((idx, out_si))
+
+    node_color = ['#ff0000' if n is source or n is sink else
+                  '#900000' if any(n in p for p in paths) else
+                  '#ffdede' if isinstance(n, Transceiver) else '#dedeff'
+                  for n in network.nodes()]
+    edge_color = ['#ff9090' if any(u in p for p in paths) and
+                               any(v in p for p in paths) else '#dedede'
+                  for u, v in network.edges()]
+
+    fig = figure()
+    plot = draw_networkx_nodes(network, pos=pos, node_size=size, node_color=node_color, figure=fig)
+    draw_networkx_edges(network, pos=pos, figure=fig, edge_color=edge_color)
+    draw_networkx_labels(network, pos=labels_pos, labels=labels, font_size=14, figure=fig)
+
+    title(f'Propagating from {source.loc.city} to {sink.loc.city}')
+    axis('off')
+    show()
+    """
+
+parser = ArgumentParser()
+parser.add_argument('filename', nargs='?', type=Path,
+  default= Path(__file__).parent / 'edfa/edfa_example_network.json')
+parser.add_argument('-v', '--verbose', action='count')
+
+if __name__ == '__main__':
+    args = parser.parse_args()
+    level = {1: INFO, 2: DEBUG}.get(args.verbose, ERROR)
+    logger.setLevel(level)
+    basicConfig()
+    exit(main(args))