Commitff7d827

murrayrm

authored and

bnavigator

committed

fix rlocus timeout due to inefficient _default_wn calculation

1 parent73f65df commitff7d827Copy full SHA for ff7d827

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2 files changed

+47

-10

lines changed

control
- rlocus.py
- tests
  - rlocus_test.py

2 files changed

+47

-10

lines changed

`‎control/rlocus.py`

Lines changed: 18 additions & 10 deletions

Original file line number	Diff line number	Diff line change
`@@ -646,8 +646,9 @@ def _sgrid_func(fig=None, zeta=None, wn=None):`
`646`	`646`	`else:`
`647`	`647`	`ax=fig.axes[1]`
`648`	`648`
`649`		`-# Get locator function for x-axis tick marks`
	`649`	`+# Get locator function for x-axis, y-axis tick marks`
`650`	`650`	`xlocator=ax.get_xaxis().get_major_locator()`
	`651`	`+ylocator=ax.get_yaxis().get_major_locator()`
`651`	`652`
`652`	`653`	`# Decide on the location for the labels (?)`
`653`	`654`	`ylim=ax.get_ylim()`
`@@ -690,7 +691,7 @@ def _sgrid_func(fig=None, zeta=None, wn=None):`
`690`	`691`	`# omega-constant lines`
`691`	`692`	`angles=np.linspace(-90,90,20)*np.pi/180`
`692`	`693`	`ifwnisNone:`
`693`		`-wn=_default_wn(xlocator(),ylim)`
	`694`	`+wn=_default_wn(xlocator(),ylocator())`
`694`	`695`
`695`	`696`	`forominwn:`
`696`	`697`	`ifom<0:`
`@@ -746,7 +747,7 @@ def _default_zetas(xlim, ylim):`
`746`	`747`	`returnzeta.tolist()`
`747`	`748`
`748`	`749`
`749`		`-def_default_wn(xloc,ylim):`
	`750`	`+def_default_wn(xloc,yloc,max_lines=7):`
`750`	`751`	`"""Return default wn for root locus plot`
`751`	`752`
`752`	`753`	`This function computes a list of natural frequencies based on the grid`
`@@ -758,23 +759,30 @@ def _default_wn(xloc, ylim):`
`758`	`759`	`List of x-axis tick values`
`759`	`760`	`ylim : array_like`
`760`	`761`	`List of y-axis limits [min, max]`
	`762`	`+ max_lines : int, optional`
	`763`	`+ Maximum number of frequencies to generate (default = 7)`
`761`	`764`
`762`	`765`	`Returns`
`763`	`766`	`-------`
`764`	`767`	`wn : list`
`765`	`768`	`List of default natural frequencies for the plot`
`766`	`769`
`767`	`770`	`"""`
	`771`	`+sep=xloc[1]-xloc[0]# separation between x-ticks`
	`772`	`+`
	`773`	`+# Decide whether to use the x or y axis for determining wn`
	`774`	`+ifyloc[-1]/sep>max_lines*10:`
	`775`	`+# y-axis scale >> x-axis scale`
	`776`	`+wn=yloc# one frequency per y-axis tick mark`
	`777`	`+else:`
	`778`	`+wn=xloc# one frequency per x-axis tick mark`
`768`	`779`
`769`		`-wn=xloc# one frequency per x-axis tick mark`
`770`		`-sep=xloc[1]-xloc[0]# separation between ticks`
`771`		`-`
`772`		`-# Insert additional frequencies to span the y-axis`
`773`		`-whilenp.abs(wn[0])<ylim[1]:`
`774`		`-wn=np.insert(wn,0,wn[0]-sep)`
	`780`	`+# Insert additional frequencies to span the y-axis`
	`781`	`+whilenp.abs(wn[0])<yloc[-1]:`
	`782`	`+wn=np.insert(wn,0,wn[0]-sep)`
`775`	`783`
`776`	`784`	`# If there are too many values, cut them in half`
`777`		`-whilelen(wn)>7:`
	`785`	`+whilelen(wn)>max_lines:`
`778`	`786`	`wn=wn[0:-1:2]`
`779`	`787`
`780`	`788`	`returnwn`

`‎control/tests/rlocus_test.py`

Lines changed: 29 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -8,6 +8,7 @@`
`8`	`8`	`fromnumpy.testingimportassert_array_almost_equal`
`9`	`9`	`importpytest`
`10`	`10`
	`11`	`+importcontrolasct`
`11`	`12`	`fromcontrol.rlocusimportroot_locus,_RLClickDispatcher`
`12`	`13`	`fromcontrol.xferfcnimportTransferFunction`
`13`	`14`	`fromcontrol.statespimportStateSpace`
`@@ -74,3 +75,31 @@ def test_root_locus_zoom(self):`
`74`	`75`
`75`	`76`	`assert_array_almost_equal(zoom_x,zoom_x_valid)`
`76`	`77`	`assert_array_almost_equal(zoom_y,zoom_y_valid)`
	`78`	`+`
	`79`	`+deftest_rlocus_default_wn(self):`
	`80`	`+"""Check that default wn calculation works properly"""`
	`81`	`+#`
	`82`	`+# System that triggers use of y-axis as basis for wn (for coverage)`
	`83`	`+#`
	`84`	`+# This system generates a root locus plot that used to cause the`
	`85`	`+# creation (and subsequent deletion) of a large number of natural`
	`86`	+# frequency contours within the `_default_wn` function in `rlocus.py`.
	`87`	`+# This unit test makes sure that is fixed by generating a test case`
	`88`	`+# that will take a long time to do the calculation (minutes).`
	`89`	`+#`
	`90`	`+importscipyassp`
	`91`	`+importsignal`
	`92`	`+`
	`93`	`+# Define a system that exhibits this behavior`
	`94`	`+sys=ct.tf(*sp.signal.zpk2tf(`
	`95`	`+ [-1e-2,1-1e7j,1+1e7j], [0,-1e7j,1e7j],1))`
	`96`	`+`
	`97`	`+# Set up a timer to catch execution time`
	`98`	`+defsignal_handler(signum,frame):`
	`99`	`+raiseException("rlocus took too long to complete")`
	`100`	`+signal.signal(signal.SIGALRM,signal_handler)`
	`101`	`+`
	`102`	`+# Run the command and reset the alarm`
	`103`	`+signal.alarm(2)# 2 second timeout`
	`104`	`+ct.root_locus(sys)`
	`105`	`+signal.alarm(0)# reset the alarm`

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Commitff7d827

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`‎control/rlocus.py`

`‎control/tests/rlocus_test.py`

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