RuntimeWarnings

[FQMei]

Hi, first of all, thank you for your great work! I have encountered an issue where some grids in my data contain only 'NaN' values and I am receiving warning messages. Despite diligently searching for information to identify the root cause of the issue, I have not found any useful information so far.

I was wondering if you could provide me with any advice or insights on how I can effectively tackle this problem and come up with a solution? Any help would be greatly appreciated.

[josuemtzmo]

Hello @FQMei,

Apologies for the slow reply, but I was on leave. A while ago, I noticed a bug, when the input data had nan values. This should be fixed in the latest version of the code, but could you check if you have the fix (quoted below) is in the file: xarrayMannKendall/xarrayMannKendall.py. If the fix is included, I will need a bit more information to debug it, i.e. when you say some grids, what do you mean? Does the output matrix contains data (note that the screenshot you sent are only RuntimeWarnings, not Errors)?

There was an issue on handling nan values, where the x coordinate was assigned to [0,0] instead of [0,1].

Error:

xarrayMannKendall/xarrayMannKendall/xarrayMannKendall.py

Lines 124 to 129 in a994fbf

	def _check_length(self):
	# Make sure that x and y have the same length and they are not empty.
	if not self.x.size > 0 or not self.y.size > 0 or self.n ==0:
	self.x = np.array([0,0])
	self.y = np.array([0,0])
	self.n = len(self.y)

Fix:

xarrayMannKendall/xarrayMannKendall/xarrayMannKendall.py

Lines 124 to 129 in cd78792

	def _check_length(self):
	# Make sure that x and y have the same length and they are not empty.
	if not self.x.size > 0 or not self.y.size > 0 or self.n ==0:
	self.x = np.array([0,1])
	self.y = np.array([0,0])
	self.n = len(self.y)

[FQMei]

Thanks for your reply @josuemtzmo

1. I have the fix in the file.
2. I use geographic data for analysis, including longitude, latitude, time, and temperature information, so "grid" means a cell containing temperature (y) and time (x) in a specific location.
3. The output matrix contains no data.

[josuemtzmo]

Which version of XarrayMannKendall are you using?

[FQMei]

1.4.5, I think.

[josuemtzmo]

Hello @FQMei, I can’t not see why the code isn’t working for you. In order for me to help you more solving the issue, could you share a test case so I can reproduce it on my side?

[FQMei]

Hi, thanks for your reply!!! If I remember well, the bug appeared in the file that you can download here: https://ufile.io/vi4ubhie

Let me know if this URL is valid.

And the code I use maybe like this:
ds = xr.open_dataset(file_path)
ds = ds.precipitation.sel(time=slice("2003-01-01", "2019-12-01")).transpose("time", "lat", "lon")
ds_yr = ds.groupby('time.year').mean(dim='time', skipna=True)
mk_test = Mann_Kendall_test(ds_yr, dim='time', MK_modified=False, method='theilslopes', coords_name={'time': 'time', 'x': 'lon', 'y': 'lat'}
result = mk_test.compute()

Thanks again for your kind help!