improve softcal

- be more tolerant parsing header of .340 file
- when curve not found, look also in secop_psi/calcurves
- better error message when curve not readable
- check that data points are monotonic
- auto create description if missing
- some more minor stuff

Change-Id: Iecc4dd3dda843b44391aa56272840472a61d4b2c
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27909
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop_psi/softcal.py

@@ -22,12 +22,12 @@
 
 import math
 import os
-from os.path import basename, exists, join
+from os.path import basename, dirname, exists, join
 
 import numpy as np
 from scipy.interpolate import splev, splrep  # pylint: disable=import-error
 
-from secop.core import Attached, BoolType, Parameter, Readable, StringType
+from secop.core import Attached, BoolType, Parameter, Readable, StringType, FloatRange
 
 
 def linear(x):
@@ -74,13 +74,18 @@ class Parser340(StdParser):
     def parse(self, line):
         """scan header for data format"""
         if self.header:
-            if line.startswith("Data Format"):
-                dataformat = line.split(":")[1].strip()[0]
-                if dataformat == '4':
+            key, _, value = line.partition(':')
+            if value:  # this is a header line, as it contains ':'
+                value = value.split()[0]
+                key = ''.join(key.split()).lower()
+                if key == 'dataformat':
+                    if value == '4':
                         self.logx, self.logy = True, False  # logOhm
-                elif dataformat == '5':
+                    elif value == '5':
                         self.logx, self.logy = True, True  # logOhm, logK
-            elif line.startswith("No."):
+                    elif value not in ('1', '2', '3'):
+                        raise ValueError('invalid Data Format')
+            elif 'No.' in line:
                 self.header = False
             return
         super().parse(line)
@@ -104,7 +109,9 @@ class CalCurve:
         calibname = sensopt.pop(0)
         _, dot, ext = basename(calibname).rpartition('.')
         kind = None
-        for path in os.environ.get('FRAPPY_CALIB_PATH', '').split(','):
+        pathlist = os.environ.get('FRAPPY_CALIB_PATH', '').split(',')
+        pathlist.append(join(dirname(__file__), 'calcurves'))
+        for path in pathlist:
             # first try without adding kind
             filename = join(path.strip(), calibname)
             if exists(filename):
@@ -134,13 +141,26 @@ class CalCurve:
         cls, args = KINDS.get(kind, (StdParser, {}))
         args.update(optargs)
 
+        try:
             parser = cls(**args)
             with open(filename) as f:
                 for line in f:
                     parser.parse(line)
+        except Exception as e:
+            raise ValueError('calib curve %s: %s' % (calibspec, e)) from e
         self.convert_x = nplog if parser.logx else linear
         self.convert_y = npexp if parser.logy else linear
-        self.spline = splrep(np.asarray(parser.xdata), np.asarray(parser.ydata), s=0)
+        x = np.asarray(parser.xdata)
+        y = np.asarray(parser.ydata)
+        if np.all(x[:-1] > x[1:]):  # all decreasing
+            x = np.flip(x)
+            y = np.flip(y)
+        elif np.any(x[:-1] >= x[1:]):  # some not increasing
+            raise ValueError('calib curve %s is not monotonic' % calibspec)
+        try:
+            self.spline = splrep(x, y, s=0, k=min(3, len(x) - 1))
+        except (ValueError, TypeError) as e:
+            raise ValueError('invalid calib curve %s' % calibspec) from e
 
     def __call__(self, value):
         """convert value
@@ -156,7 +176,7 @@ class Sensor(Readable):
 
     calib = Parameter('calibration name', datatype=StringType(), readonly=False)
     abs = Parameter('True: take abs(raw) before calib', datatype=BoolType(), readonly=False, default=True)
-    value = Parameter(unit='K')
+    value = Parameter(datatype=FloatRange(unit='K'))
     pollinterval = Parameter(export=False)
     status = Parameter(default=(Readable.Status.ERROR, 'unintialized'))
 
@@ -164,10 +184,17 @@ class Sensor(Readable):
     _value_error = None
     enablePoll = False
 
+    def checkProperties(self):
+        if 'description' not in self.propertyValues:
+            self.description = '_'  # avoid complaining about missing description
+        super().checkProperties()
+
     def initModule(self):
         super().initModule()
         self._rawsensor.registerCallbacks(self, ['status'])  # auto update status
         self._calib = CalCurve(self.calib)
+        if self.description == '_':
+            self.description = '%r calibrated with curve %r' % (self.rawsensor, self.calib)
 
     def write_calib(self, value):
         self._calib = CalCurve(value)
@@ -175,7 +202,7 @@ class Sensor(Readable):
 
     def update_value(self, value):
         if self.abs:
-            value = abs(value)
+            value = abs(float(value))
         self.value = self._calib(value)
         self._value_error = None