Bug fix in spectral processor

There was a bug in the flip_spec function that made it work incorrectly for some specific transformations (specific orientiation of the directional vector and directional resolution). This bug has been fixed and unit tests have been expanded.

The boundary reader for reading WW3 netcdf-files was corrected for a bug in reading the directions from the xarray dataset and some function handles were harmonized with the rest of the code.

Author: bjorkqvi

dnora/aux.py

@@ -331,10 +331,13 @@ def flip_spec(spec, D):
     spec_flip = np.zeros(spec.shape)
 
     ind = np.arange(0,len(D), dtype='int')
-    dD = np.diff(D).mean()
+    #dD = np.diff(D).mean()
+    dD = 360/len(D)
     steps = D/dD # How many delta-D from 0
 
-    ind_flip = ((ind - 2*steps).astype(int) + len(D)) % len(D)
+    # Need to move indeces the other way if the vector is decreasing than if it is increasing
+    direction = np.sign(np.median(np.diff(D)))
+    ind_flip = ((ind - 2*steps*direction).astype(int) + len(D)) % len(D)
 
     spec_flip=spec[..., list(ind_flip)]
 
@@ -360,8 +363,8 @@ def shift_spec(spec, D, shift=0):
     ind = np.arange(0,len(D), dtype='int')
     dD = 360/len(D)
 
-    if abs(np.floor(dD)-dD) > 0:
-        raise Exception ('Shift needs to be multiple of frequency resolution! Otherwise interpolation would be needed.')
+    if abs(np.floor(shift/dD)-shift/dD) > 0:
+        raise Exception (f'Shift {shift} needs to be multiple of frequency resolution {dD}, but shift/dD={shift/dD}! Otherwise interpolation would be needed.')
 
     ind_flip = ((ind + int(shift/dD)).astype(int) + len(D)) % len(D)
 

dnora/bnd/read.py

@@ -91,7 +91,7 @@ def __call__(self, start_time, end_time, inds) -> Tuple:
 
 
 class File_WW3Nc(BoundaryReader):
-    def __init__(self, folder: str='', filestring: str='ww3_T0', datestring: str='%Y%m%dT%H%M', stride: int=6, hours_per_file: int=73, last_file: str='', lead_time: int=0) -> None:
+    def __init__(self, folder: str='', filename: str='ww3_T0', dateftm: str='%Y%m%dT%H%M', stride: int=6, hours_per_file: int=73, last_file: str='', lead_time: int=0) -> None:
         self.stride = copy(stride)
         self.hours_per_file = copy(hours_per_file)
         self.lead_time = copy(lead_time)
@@ -102,8 +102,8 @@ def __init__(self, folder: str='', filestring: str='ww3_T0', datestring: str='%Y
         else:
             self.folder = copy(folder)
 
-        self.filestring = copy(filestring)
-        self.datestring = copy(datestring)
+        self.filestring = copy(filename)
+        self.datestring = copy(dateftm)
 
         return
 
@@ -149,7 +149,7 @@ def __call__(self, start_time, end_time, inds) -> Tuple:
 
         time = bnd.time.values
         freq = bnd.frequency.values
-        dirs = bnd.directions.values
+        dirs = bnd.direction.values
         spec = bnd.efth.values
         lon = bnd.longitude.values[0,:]
         lat = bnd.latitude.values[0,:]

tests/unittests/run_unit_tests.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+ls utest*.py > utests.txt
+
+while read test; do
+  echo "Running test: "$test
+  python $test
+done < utests.txt
+
+rm utests.txt