Graph and post process simulator data
PyPost is intended to be a replacement for Nutmeg, which is the post processor for data created by NGSpice and other circuit simulators. The advantage of this program is that it uses Qt and does not require X-Windows. It is written in Python and uses matplotlib. A Python REPL loop is the expression evaluator. This brings in a large number of commands from Python, Numpy, and other modules.
PyPost is an iPython alternative designed for engineers working with simulators. If you are not interacting with a circuit simulator, you might prefer iPython.
ci <fn>
Stands for 'circuit is: '.
Sets the name of the circuit to be sent to the simulator.
<fn>
is the base name of the simulation deck.
<expr>
Evaluates an expression. Expressions have access to simulator results. Voltages are v(netname) and currents are i(devicename). The time axis is the variable t Expressions can also be vectors or other numpy expressions. Expressions can have side effects, since much of the Python language and numpy is available.
gr <expr>
Graphs and expression versus xname. If there is no x-axis, a list of integers starting at 0 are used instead.
If the expression is an image, the image is displayed.
For now it is not possible to display an image on top of an existing graph.
Use the set graphdev
command to create a new
gs
Graph using the same axes.
<var>=<expr>
Set a variable <var>
to the expression <expr>
.
Example:
set xname x
n=201
x=linspace(0, 2*pi, n)
gr sin(10*x)*hanning(n)
set
Shows the current values of the plot settings
set yl <number> <number>
Sets the y limits of the graph.
set yl auto
Sets the y axis to use autoranging.
set xl <number> <number>
Sets the x limits of the graph.
set xl auto
Sets the x axis to use autoranging.
set xname <var>
Sets the sweep variable (x axis) to the variable Example:
set xname x
set graphdev winname
If the window winname already exists, the set graphdev command sets this window to the active graph. If the window with this name does not exist yet, it creates a new window for drawing graphs or images. The window will appear when a graph or image is drawn on it. The name of the the default graph which appears in the PyPost interface is PyPost_1. It is not possible at this time to draw an image in this area.
si
Runs the circuit simulator on the current simulation deck.
si <filename>
Runs the circuit simulator on the specified file.
ci <basename>
Sets the simulator base file name to . This example sets the simulation basename to ngtest in the directory t:
ci t/ngtest
The simulator uses the basename to create file names.
For NGSpice, the input file will be t/ngtest.cki
The output file will be t/ngtest.raw
ci
Displays the current simulation base file name
history
Show past commands entered into the post processor.
The arrow keys also work to recall previous commands.
readh5
Not implemented yet.
img <filename>
Reads an image file into a variable.
The name of the variable is the basename of the file.
Example:
img t/yellow.png
reads the file in the subdirectory t
into the variable yellow
.
include <filename>
Reads the file at <filename>
and executes it as a list of commands as if they were typed in.
. <filename>
Synonym for include. Saves typing.
__di__
Displays the simulation variables that are available to be plotted or used in expressions.
The mouse scroll-wheel provides zooming and panning for graphs. Depending on where the mouse pointer is located, the wheel has different actions.
Inside the graph area, panning and zooming occurs on the X-axis. In the left and right sides of the graph, the scroll-wheel provides panning. In the middle area of the graph, the scroll-wheel provides zooming.
Outside the graph area, panning and zooming occurs on the Y-axis. In the top and bottom area outside of the graph, the scroll-wheel provides panning. In the middle area outside of the graph, the scroll-wheel provides zooming.
Clicking on a waveform in the graph sets a marker at the X position of the mouse pointer, and it reports the value of the waveform at the Y position corresponding to this X position.