Issue | Unable to Run basic "astable.py" example file with Xyce

[rowhit]

Environment (OS, Python version, PySpice version, simulator)

Operating System: Ubuntu 20.04 PySpice Version: 1.4.3 Simulator: Xyce (7.2 Opensource Version)

Expected Vs Actual Behaviour

• The above mentioned "astable.py" netlist script provided in the example works fine with ngspice, however, fails for the Xyce.
• The generated spice netlist cannot be parsed and run with Xyce.
• Another python netlist operational-amplifier.py provided works fine with xyce-parallel (Xyce is functional).

.title Astable Multivibrator
Vcc vcc 0 15V
R1 output comparator 1kOhm
C1 comparator 0 100nF
R2 output reference 100kOhm
R3 vcc reference 100kOhm
R4 reference 0 100kOhm
E1 output 0 TABLE {V(reference, comparator)} = (-1u, 0) (1u, 15V)
.options TEMP = 25
.options TNOM = 25
.ic V(comparator)=0
.tran 1us 500us 0s
.end

Steps to reproduce the behavior

• Run the following script astable.py script which contains simualtor="xyce-parallel".
• Please do copy other dependent scripts (OperationalAmplifier.py) from here https://pyspice.fabrice-salvaire.fr/releases/v1.4/examples/operational-amplifier/index.html
• Run python astable.py

####################################################################################################

import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.use('Qt5Agg')

####################################################################################################

import PySpice.Logging.Logging as Logging
logger = Logging.setup_logging()

####################################################################################################

from PySpice.Probe.Plot import plot
from PySpice.Spice.Netlist import Circuit
from PySpice.Unit import *

# from OperationalAmplifier import basic_comparator

####################################################################################################

circuit = Circuit('Astable Multivibrator')

source = circuit.V('cc', 'vcc', circuit.gnd, 15@u_V)
# Time constant
circuit.R(1, 'output', 'comparator', 1@u_kΩ)
circuit.C(1, 'comparator', circuit.gnd, 100@u_nF)
# Reference
circuit.R(2, 'output', 'reference', 100@u_kΩ)
circuit.R(3, 'vcc', 'reference', 100@u_kΩ)
circuit.R(4, 'reference', circuit.gnd, 100@u_kΩ)
# Comparator
# Fixme: ngspice is buggy with such subcircuit
# circuit.subcircuit(basic_comparator)
# circuit.X('comparator', 'BasicComparator', 'reference', 'comparator', 'vcc', circuit.gnd, 'output')
circuit.NonLinearVoltageSource(1, 'output', circuit.gnd,
                               expression='V(reference, comparator)',
                               table=((-micro(1), 0),
                                      (micro(1), source.dc_value))
                               )

simulator = circuit.simulator(simulator="xyce-parallel", temperature=25, nominal_temperature=25)
simulator.initial_condition(comparator=0)  # Fixme: simulator.nodes.comparator == 0
analysis = simulator.transient(step_time=1@u_us, end_time=500@u_us)
# Fixme: Xyce fails with Time step too small

figure, ax = plt.subplots(figsize=(20, 10))
ax.grid()
ax.plot(analysis.reference)
ax.plot(analysis.comparator)
ax.plot(analysis.output)

plt.tight_layout()
plt.show()

#f# save_figure('figure', 'astable.png')

[FabriceSalvaire]

see also #40