Cadence PSF file utilities
Project description
- Author:
Ken Kundert
- Version:
0.5.0
- Released:
2020-01-08
What?
psf_utils is a library allows you to read data from a Spectre PSF ASCII file. Spectre is a commercial circuit simulator produced by Cadence Design Systems. PSF files contain signals generated by Spectre. This package also contains two programs that are useful in their own right, but also act as demonstrators as to how to use the library. They are list-psf and plot-psf. The first lists the available signals in a file, and the other displays them.
Accessing the Results
You can use the PSF class to read ASCII Parameter Storage Format files. When instantiating the class you pass in the path to the file and then the resulting PSF object contains a dictionary that containing the signals. For example, the following lists is a:
from psf_utils import PSF from inform import Error, display kinds = { 'float double': 'real', 'float complex': 'complex', } try: psf = PSF('adc.raw/tran.tran') for signal in psf.all_signals(): kind = signal.type.kind kind = kinds.get(kind, kind) display(f'{signal.name:<15} {signal.units:<12} {kind}') except Error as e: e.terminate()
This example plots the output signal:
from psf_utils import PSF from inform import Error, display import matplotlib.pyplot as plt try: psf = PSF('adc.raw/tran.tran') sweep = psf.get_sweep() out = psf.get_signal('out') figure = plt.figure() axes = figure.add_subplot(1,1,1) axes.plot(sweep.abscissa, out.ordinate, linewidth=2, label=out.name) axes.set_title('ADC Output') axes.set_xlabel(f'{sweep.name} ({PSF.units_to_unicode(sweep.units)})') axes.set_ylabel(f'{out.name} ({PSF.units_to_unicode(out.units)})') plt.show() except Error as e: e.terminate()
abscissa and ordinate are NumPy arrays.
Utility Programs
Two utility programs are installed along with the psf_utils library: list-psf and plot-psf. The first lists the signals available from a PSF file, and the second displays them. They both employ caching to speed up access to the data. They also cache the name of the PSF file so that it need not be given every time. plot-psf also caches its arguments, so if you run it again with no arguments it will simply repeat what it did last time. For example, here is a typical session:
# display signals in PSF file > list-psf -f resistor.raw/pnoise.pnoise Using pnoise.raw/pnoise.pnoise. R1:flicker R1:total R2:fn out R1:thermal R2:rn R2:total # display them again, this time in long form > list-psf -l Using pnoise.raw/pnoise.pnoise. R1:flicker A²/Hz real (12042 points) R1:thermal A²/Hz real (12042 points) R1:total A²/Hz real (12042 points) R2:fn A²/Hz real (12042 points) R2:rn A²/Hz real (12042 points) R2:total A²/Hz real (12042 points) out A/√Hz real (12042 points) # display only those that match R1:* > list-psf -l R1:* Using pnoise.raw/pnoise.pnoise. R1:flicker A²/Hz real (12042 points) R1:thermal A²/Hz real (12042 points) R1:total A²/Hz real (12042 points) # display a graph containing signals that start with R1: > plot-psf R1:* # display the thermal noise of R1, and then the total noise minue the flicker noise > plot-psf R1:thermal R1:total-R1:flicker # display a graph containing only out > plot-psf out > plot-psf # display out again
Converting to PSF ASCII
psf_utils only supports PSF ASCII files. As an alternative, libpsf is a Python package that can read both ASCII and binary PSF files. Or, you can use the Cadence psf program to convert various types of simulation results files into PSF ASCII format. To use it, simply specify the input and output files:
> psf -i adc.raw/tran.tran -o adc.raw/tran.psfascii > list-psf -f adc.raw/tran.psfascii
In this example there is nothing special about the ‘psfascii’ suffix, it is simply mnemonic. Rather, the output is in ASCII format because the -b (binary) option is not specified.
Releases
- Latest development release:
- Version: 0.5.0Released: 2020-01-08
- 0.4 (2019-09-26):
Allow glob patterns to be passed to both list-psf and plot-psf.
- 0.3 (2019-09-25):
Fix import errors in plot-psf command.
- 0.2 (2019-09-25):
Fix dependencies.
- 0.1 (2019-09-25):
Initial version
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