LISO tools¶

Hint

Also see the documentation on LISO compatibility.

Zero can parse LISO input and output files, run them natively or run them via a local LISO binary and display the results. It can also compare its native results to that of LISO by overlaying results in a plot or displaying a table of values.

Script path¶

For all calls to zero liso, one or more script paths (FILE) must be specified. These can either be LISO input or output file (commonly given .fil and .out extensions, respectively), and Zero will choose an appropriate parser based on what it finds.

When more than one script is specified, they are simulated separately and the results combined. See Simulating multiple input files together for more information.

Verbose output¶

By default, the command line utility does not output any text except that which is requested. Verbosity can be switched on with the -v flag. Specify -vv for greater verbosity.

Note

The -v flag must be specified before the liso subcommand, i.e. zero -v liso [FILE]. An error will occur if the flag is specified after a subcommand.

Simulating a LISO input script with Zero¶

LISO input scripts can be run natively with the zero liso command. The input file is first parsed and then built into an analysis which is then solved.

$ zero liso /path/to/liso/script.fil

The plotted functions specified in the LISO input file are reproduced in the default Zero plot, including noise sums.

Re-simulating a LISO output file with Zero¶

LISO result files contain a complete description of the simulated circuit, and as such can be parsed by Zero and re-simulated natively.

$ zero liso /path/to/liso/script.out

Simulating a LISO input script with an external LISO binary¶

Zero can simulate a LISO input script with a locally installed LISO binary using the --liso flag. Zero runs the script with LISO and then parses the output file so that you can take advantage of its plotting capabilities.

The LISO binary path must be specified with the --liso-path option. This must point to the exact binary file, not just its directory, but may be relative to the current directory.

$ zero liso /path/to/liso/script.fil --liso --liso-path /path/to/liso/fil

An alternative is to set the LISO_PATH environment variable to point to the LISO binary. Since LISO anyway requests that users set the LISO_DIR environment variable, on Unix systems this can be used to set LISO_PATH either in the terminal profile (e.g. during the call with e.g. LISO_PATH=$LISO_DIR/fil_static zero liso ...) or as part of the call:

$ LISO_PATH=$LISO_DIR/fil_static zero liso /path/to/liso/script.fil --liso

Warning

LISO uses a separate op-amp library to Zero, and these may differ if modifications have been made to one but not the other. Take care when comparing results between the two tools.

Comparing a native simulation to LISO¶

As Zero can simulate LISO input scripts both natively and using the LISO binary, it can also overlay the results on one plot, or report the difference between the results textually.

To overlay the results in a plot, specify the --compare flag. Zero will then run the specified input file itself and with LISO, then it will parse the LISO results and combine them with its own. The resulting plot then contains each function, with the native results with solid lines and the LISO results with dashed lines:

A textual representation of the differences can also be displayed by specifying --diff. This must be provided in addition to --compare. When specified, this prints a table containing the worst relative and absolute differences between the two solutions, and the frequencies at which they occur:

╒══════════════════╤═══════════════════════════════╤═══════════════════════════════╕
│                  │ Worst difference (absolute)   │ Worst difference (relative)   │
╞══════════════════╪═══════════════════════════════╪═══════════════════════════════╡
│ nin to op1 (A/V) │ 1.08e-11 (f = 316.23 kHz)     │ 9.78e-10 (f = 316.23 kHz)     │
├──────────────────┼───────────────────────────────┼───────────────────────────────┤
│ nin to no (V/V)  │ 1.04e-08 (f = 79.433 kHz)     │ 9.54e-10 (f = 79.433 kHz)     │
╘══════════════════╧═══════════════════════════════╧═══════════════════════════════╛

Simulating multiple input files together¶

Multiple input or output files may be specified in the zero liso call. These are simulated separately and the results are merged together such that they can be plotted on one graph if possible. The results can only be combined with the simulations contain the same frequency vectors. If they do not have the same frequency vectors, an error is displayed and the program exits.

This can be useful for example for simulating similar circuits with different component values on one graph. Each script is plotted with a different line style and a gradually lighter colour map.

Here is an example that shows the noise at an output node and the same noise referred to the input on one plot:

$ zero liso noise1.fil noise2.fil

Contents of noise1.fil:

r r1 400k nin n1
r r2 400k n1 n2
r r3 50 n5 n3
r rs 230 n5 n6
r led 48.6 n6 gnd
c c1 20u n1 n3
c c2 10u n2 gnd
op op1 op27 n2 n3 n4
op op2 buf634 n4 n5 n5

freq log .003 300 1000

uinput nin 0
noise n6 sum
noisy all

Contents of noise2.fil:

r r1 400k nin n1
r r2 400k n1 n2
r r3 50 n5 n3
r rs 230 n5 n6
r led 48.6 n6 gnd
c c1 20u n1 n3
c c2 10u n2 gnd
op op1 op27 n2 n3 n4
op op2 buf634 n4 n5 n5

freq log .003 300 1000

uinput nin 0
inputnoise n6 sum
noisy all

Scaling response plots¶

Responses can be scaled in either decibels or absolute values. The default is to scale in decibels (--resp-scale-db, on by default), but this can be switched off with the --resp-scale-abs flag.

Saving figures¶

Figures can be saved using the --save-figure option, which must be followed by a file path. The format of the figure is controlled by the specified file extension. For example, save PNGs, PDFs and SVGs with --save-figure response.png, --save-figure response.pdf and --save-figure response.svg, respectively.

The --save-figure option can be specified multiple times to save multiple figures, e.g.:

$ zero liso /path/to/liso/script.fil --save-figure response.png --save-figure response.pdf

Command reference¶

zero liso¶

Parse and simulate LISO input or output file(s). Multiple files can be specified as long as they have compatible frequency vectors. These are all simulated and combined into one solution.

zero liso [OPTIONS] [FILE]...

Options

--liso¶: Simulate using LISO.

--liso-path <liso_path>¶: Path to LISO binary. If not specified, the environment variable LISO_PATH is searched.

--resp-scale-db, --resp-scale-abs¶: Scale response y-axes in decibels. [default: True]

--compare¶: Simulate using both this tool and LISO binary, and combine the results.

--diff¶: Show difference between results of comparison.

--plot, --no-plot¶: Display results as figure. [default: True]

--save-figure <save_figure>¶: Save image of figure to file. Can be specified multiple times.

--print-equations¶: Print circuit equations.

--print-matrix¶: Print circuit matrix.

Arguments

[FILE]...¶: Optional argument(s)

Environment variables

LISO_PATH: Provide a default for --liso-path