How can I reconfigure a flow graph? How do I use lock(), unlock()?¶
A running flow graph is static, and can't be changed. There are two ways to implement reconfigurability:
- Use lock() / unlock()
- Create blocks that react dynamically
Using lock() and unlock(), you will actually stop the flow graph, and can then disconnect and re-connect blocks. In the following example, the flow graph will run for a second,
the stop the execution (lock), disconnect the source, connect a different one, and resume. The resulting file will first have data from the vector source, then lots of zeros.
#!/usr/bin/env python
import time
from gnuradio import gr
from gnuradio import blocks
def main():
tb = gr.top_block()
src1 = blocks.vector_source_f(range(16), repeat=True)
throttle = blocks.throttle(gr.sizeof_float, 1e6)
sink = blocks.file_sink(gr.sizeof_float, 'out.dat')
tb.connect(src1, throttle, sink)
tb.start()
time.sleep(1)
print "Locking flowgraph..."
tb.lock()
tb.disconnect(src1)
src2 = blocks.null_source(gr.sizeof_float)
tb.connect(src2, throttle)
print "Unlocking flowgraph..."
tb.unlock()
time.sleep(2)
tb.stop()
tb.wait()
if __name__ == "__main__":
main()
Note that this is not meant for sample-precision timing, but rather for situations where time does not really matter.
If sample-timing is an issue, use general blocks to react to certain events. In the following example, we assume that you have written a general block which stops reading from the
first sink at a given time, and then seamlessly switches over to the second input:
#!/usr/bin/env python
import time
from gnuradio import gr
from gnuradio import blocks
import my_awesome_oot_module as myoot # This is your custom module
def main():
tb = gr.top_block()
src1 = blocks.vector_source_f(range(16), repeat=True)
src2 = blocks.null_source(gr.sizeof_float)
switch = myoot.switch() # This is your custom block
throttle = blocks.throttle(gr.sizeof_float, 1e6)
sink = blocks.file_sink(gr.sizeof_float, 'out.dat')
tb.connect(src1, switch, throttle, sink)
tb.connect(src2, (switch, 1))
tb.start()
time.sleep(2)
tb.stop()
tb.wait()
if __name__ == "__main__":
main()
There are many blocks that react to input data, or incoming tags.
参考：http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#How-can-I-reconfigure-a-flow-graph-How-do-I-use-lock-unlock