set_parser for seq element setting added (#832)

* set_parser for seq element setting added

* Add Permissive int validator

To be used for parameters that may be set as floats but should be cast to int

* Still validate this and parse it too

qcodes/instrument_drivers/tektronix/AWG5014.py

@@ -212,7 +212,8 @@ def __init__(self, name, address, timeout=180, num_channels=4, **kwargs):
                            label='Sequence position',
                            get_cmd='AWGControl:SEQuencer:POSition?',
                            set_cmd='SEQuence:JUMP:IMMediate {}',
-                           vals=vals.Ints(1)
+                           vals=vals.PermissiveInts(1),
+                           set_parser=lambda x: int(round(x))
                            )
 
         # Trigger parameters #

qcodes/tests/test_parameter.py

@@ -5,6 +5,8 @@
 from unittest import TestCase
 from time import sleep
 
+import numpy as np
+
 from qcodes import Function
 from qcodes.instrument.parameter import (
     Parameter, ArrayParameter, MultiParameter,
@@ -250,6 +252,35 @@ def test_latest_value(self):
         self.assertEqual(p.get_latest(), 21)
         self.assertEqual(p.get_values, [21])
 
+
+class TestValsandParseParameter(TestCase):
+
+    def setUp(self):
+        self.parameter = Parameter(name='foobar',
+                                   set_cmd=None, get_cmd=None,
+                                   set_parser=lambda x: int(round(x)),
+                                   vals=vals.PermissiveInts(0))
+
+    def test_setting_int_with_float(self):
+
+        a = 0
+        b = 10
+        values = np.linspace(a, b, b-a+1)
+        for i in values:
+            self.parameter(i)
+            a = self.parameter()
+            assert isinstance(a, int)
+
+    def test_setting_int_with_float_not_close(self):
+
+        a = 0
+        b = 10
+        values = np.linspace(a, b, b-a+2)
+        for i in values[1:-2]:
+            with self.assertRaises(TypeError):
+                self.parameter(i)
+
+
 class SimpleArrayParam(ArrayParameter):
     def __init__(self, return_val, *args, **kwargs):
         self._return_val = return_val

qcodes/tests/test_validators.py

@@ -3,7 +3,8 @@
 import numpy as np
 
 from qcodes.utils.validators import (Validator, Anything, Bool, Strings,
-                                     Numbers, Ints, Enum, MultiType,
+                                     Numbers, Ints, PermissiveInts,
+                                     Enum, MultiType,
                                      Arrays, Multiples, Lists, Callable, Dict)
 
 
@@ -351,6 +352,30 @@ def test_failed_numbers(self):
                 Ints(min_value=val)
 
 
+class TestPermissiveInts(TestCase):
+
+
+    def test_close_to_ints(self):
+        validator = PermissiveInts()
+        a = 0
+        b = 10
+        values = np.linspace(a, b, b-a+1)
+        for i in values:
+            validator.validate(i)
+
+    def test_bad_values(self):
+        validator = PermissiveInts(0, 10)
+        a = 0
+        b = 10
+        values = np.linspace(a, b, b-a+2)
+        for j,i in enumerate(values):
+            if j == 0 or j == 11:
+                validator.validate(i)
+            else:
+                with self.assertRaises(TypeError):
+                    validator.validate(i)
+
+
 class TestEnum(TestCase):
     enums = [
         [True, False],

qcodes/utils/validators.py

@@ -217,6 +217,27 @@ def __repr__(self):
         maxv = self._max_value if self._max_value < BIGINT else None
         return '<Ints{}>'.format(range_str(minv, maxv, 'v'))
 
+class PermissiveInts(Ints):
+    """
+    requires an integer or a float close to an integer
+    optional parameters min_value and max_value enforce
+    min_value <= value <= max_value
+    Note that you probably always want to use this with a
+    set_parser that converts the float repr to an actual int
+    """
+    def validate(self, value, context=''):
+        if isinstance(value, (float, np.floating)):
+            intrepr = int(round(value))
+            remainder = abs(value - intrepr)
+            if remainder < 1e-05:
+                castvalue = intrepr
+            else:
+                raise TypeError('{} is not an int or close to an int'
+                                '; {}'.format(repr(value), context))
+        else:
+            castvalue = value
+        super().validate(castvalue, context=context)
+
 
 class Enum(Validator):
     """