Log scale with 0 in pyqtgraph

qt_is_not_easy

I am baffled by implementing a symlog (matplotlib equivalent for symmetric log scale) in pyqtgraph. I wonder if I can make a broken axis plot in pyqtgraph. I am attaching a sample code of a plot for reference, but I don't think that would be helpful.

Thanks in advance

import pyqtgraph as pg
from PyQt5.QtWidgets import QApplication
from pyqtgraph.Qt import QtGui
from pyqtgraph.widgets.RemoteGraphicsView import RemoteGraphicsView
# Create a PyQtGraph application instance
app = QApplication([])

# Create two PlotItems and link their X-axis
plot_item1 = pg.PlotItem()
plot_item2 = pg.PlotItem()
plot_item1.setXLink(plot_item2)

# Create some example data
x1 = [1, 2, 3, 4, 5]
x2 = [1.1, 2.1, 3.1, 4.4, 5.2]
y1 = [1, 2, 3, 2, 1]
y2 = [1, 4, 2, 3, 1]

# Plot the data on each PlotItem
plot_item1.plot(x1, y1)
plot_item2.plot(x2, y2)

# Create a layout and add the PlotItems to it
layout = pg.GraphicsLayout()
layout.addItem(plot_item1, 0, 0)
layout.addItem(plot_item2, 1, 1)
# layout.resize(500,300)

# Show the plot
# view = pg.GraphicsView()
# l = pg.GraphicsLayout()
win = pg.GraphicsView()
win.setCentralItem(layout)
win.show()

# Start the event loop
app.exec_()

thelegend27

I stumbled over the same problem and I haven't found a "symlog" for pyqtgraph yet...

Since the log value for zero can not be defined, whilst small values close to zero are defined, the zero values can be set to a value close to zero (e.g. 1e-3, or maybe even lower... e.g. 1e-10).

x = [1, 4, 0, 2, 3, 0, 1]
x[x==0] = 1-e3

print(x) --> x = [1, 4, 0.001, 2, 3, 0.001, 1]

I hope this helps in some way.
Kind regards