feat: Bookkeep fixed parameters

src/pyhf/modifiers/histosys.py

@@ -20,6 +20,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': True,
             'inits': (0.0,),
             'bounds': ((-5.0, 5.0),),
+            'fixed': False,
             'auxdata': (0.0,),
         }
 

src/pyhf/modifiers/lumi.py

@@ -20,6 +20,7 @@ def required_parset(cls, sample_data, modifier_data):
             'op_code': cls.op_code,
             'inits': None,  # lumi
             'bounds': None,  # (0, 10*lumi)
+            'fixed': False,
             'auxdata': None,  # lumi
             'sigmas': None,  # lumi * lumirelerror
         }

src/pyhf/modifiers/normfactor.py

@@ -19,6 +19,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': True,
             'inits': (1.0,),
             'bounds': ((0, 10),),
+            'fixed': False,
         }
 
 

src/pyhf/modifiers/normsys.py

@@ -20,6 +20,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': True,
             'inits': (0.0,),
             'bounds': ((-5.0, 5.0),),
+            'fixed': False,
             'auxdata': (0.0,),
         }
 

src/pyhf/modifiers/shapefactor.py

@@ -19,6 +19,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': True,
             'inits': (1.0,) * len(sample_data),
             'bounds': ((0.0, 10.0),) * len(sample_data),
+            'fixed': False,
         }
 
 

src/pyhf/modifiers/shapesys.py

@@ -27,6 +27,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': False,
             'inits': (1.0,) * n_parameters,
             'bounds': ((1e-10, 10.0),) * n_parameters,
+            'fixed': False,
             # nb: auxdata/factors set by finalize. Set to non-numeric to crash
             # if we fail to set auxdata/factors correctly
             'auxdata': (None,) * n_parameters,

src/pyhf/modifiers/staterror.py

@@ -19,6 +19,7 @@ def required_parset(cls, sample_data, modifier_data):
             'is_shared': True,
             'inits': (1.0,) * len(sample_data),
             'bounds': ((1e-10, 10.0),) * len(sample_data),
+            'fixed': False,
             'auxdata': (1.0,) * len(sample_data),
         }
 

src/pyhf/parameters/paramsets.py

@@ -6,6 +6,7 @@ def __init__(self, **kwargs):
         self.n_parameters = kwargs.pop('n_parameters')
         self.suggested_init = kwargs.pop('inits')
         self.suggested_bounds = kwargs.pop('bounds')
+        self.fixed = kwargs.pop('fixed')
 
 
 class unconstrained(paramset):

src/pyhf/parameters/utils.py

@@ -12,6 +12,7 @@ def reduce_paramsets_requirements(paramsets_requirements, paramsets_user_configs
         'auxdata',
         'factors',
         'sigmas',
+        'fixed',
     ]
 
     # - process all defined paramsets
@@ -27,6 +28,7 @@ def reduce_paramsets_requirements(paramsets_requirements, paramsets_user_configs
         combined_paramset = {}
         for k in paramset_keys:
             for paramset_requirement in paramset_requirements:
+                # undefined: the modifier does not support configuring that property
                 v = paramset_requirement.get(k, 'undefined')
                 combined_paramset.setdefault(k, set([])).add(v)
 

src/pyhf/pdf.py

@@ -93,6 +93,7 @@ def _paramset_requirements_from_modelspec(spec, channel_nbins):
         paramset_type = paramset_requirements.get('paramset_type')
         paramset = paramset_type(**paramset_requirements)
         _sets[param_name] = paramset
+
     return _sets
 
 
@@ -229,8 +230,8 @@ def __init__(self, spec, **config_kwargs):
         )
 
         if config_kwargs:
-            raise KeyError(
-                f"""Unexpected keyword argument(s): '{"', '".join(config_kwargs.keys())}'"""
+            raise exceptions.Unsupported(
+                f"Unsupported options were passed in: {list(config_kwargs.keys())}."
             )
 
         self.par_map = {}
@@ -265,6 +266,31 @@ def par_slice(self, name):
     def param_set(self, name):
         return self.par_map[name]['paramset']
 
+    def suggested_fixed(self):
+        """
+        Identify the fixed parameters in the model.
+
+        Returns:
+            List: A list of booleans, ``True`` for fixed and ``False`` for not fixed.
+
+        Something like the following to build fixed_vals appropriately:
+
+        .. code:: python
+
+            fixed_pars = pdf.config.suggested_fixed()
+            inits = pdf.config.suggested_init()
+            fixed_vals = [
+                (index, init)
+                for index, (init, is_fixed) in enumerate(zip(inits, fixed_pars))
+                if is_fixed
+            ]
+        """
+        fixed = []
+        for name in self.par_order:
+            paramset = self.par_map[name]['paramset']
+            fixed = fixed + [paramset.fixed] * paramset.n_parameters
+        return fixed
+
     def set_poi(self, name):
         if name not in [x for x, _ in self.modifiers]:
             raise exceptions.InvalidModel(

tests/test_combined_modifiers.py

@@ -5,7 +5,12 @@
 from pyhf.modifiers.shapesys import shapesys_combined
 from pyhf.modifiers.normfactor import normfactor_combined
 from pyhf.modifiers.shapefactor import shapefactor_combined
-from pyhf.parameters import paramset
+from pyhf.parameters import (
+    paramset,
+    unconstrained,
+    constrained_by_normal,
+    constrained_by_poisson,
+)
 import numpy as np
 import pyhf
 
@@ -42,11 +47,23 @@ def test_histosys(backend):
     mc = MockConfig(
         par_map={
             'hello': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[-5, 5]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[-5, 5]],
+                    fixed=False,
+                    auxdata=[0.0],
+                ),
                 'slice': slice(0, 1),
             },
             'world': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[-5, 5]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[-5, 5]],
+                    fixed=False,
+                    auxdata=[0.0],
+                ),
                 'slice': slice(1, 2),
             },
         },
@@ -131,11 +148,23 @@ def test_normsys(backend):
     mc = MockConfig(
         par_map={
             'hello': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[-5, 5]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[-5, 5]],
+                    fixed=False,
+                    auxdata=[0.0],
+                ),
                 'slice': slice(0, 1),
             },
             'world': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[-5, 5]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[-5, 5]],
+                    fixed=False,
+                    auxdata=[0.0],
+                ),
                 'slice': slice(1, 2),
             },
         },
@@ -222,7 +251,14 @@ def test_lumi(backend):
     mc = MockConfig(
         par_map={
             'lumi': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[-5, 5]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[-5, 5]],
+                    fixed=False,
+                    auxdata=[None],
+                    sigmas=[None],
+                ),
                 'slice': slice(0, 1),
             }
         },
@@ -272,12 +308,22 @@ def test_stat(backend):
     mc = MockConfig(
         par_map={
             'staterror_chan1': {
-                'paramset': paramset(n_parameters=1, inits=[1], bounds=[[0, 10]]),
+                'paramset': constrained_by_normal(
+                    n_parameters=1,
+                    inits=[1],
+                    bounds=[[0, 10]],
+                    fixed=False,
+                    auxdata=[1],
+                ),
                 'slice': slice(0, 1),
             },
             'staterror_chan2': {
-                'paramset': paramset(
-                    n_parameters=2, inits=[1, 1], bounds=[[0, 10], [0, 10]]
+                'paramset': constrained_by_normal(
+                    n_parameters=2,
+                    inits=[1, 1],
+                    bounds=[[0, 10], [0, 10]],
+                    fixed=False,
+                    auxdata=[1, 1],
                 ),
                 'slice': slice(1, 3),
             },
@@ -349,21 +395,37 @@ def test_shapesys(backend):
     mc = MockConfig(
         par_map={
             'dummy1': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': paramset(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(0, 1),
             },
             'shapesys1': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': constrained_by_poisson(
+                    n_parameters=1,
+                    inits=[0],
+                    bounds=[[0, 10]],
+                    fixed=False,
+                    auxdata=[None],
+                    factors=[None],
+                ),
                 'slice': slice(1, 2),
             },
             'shapesys2': {
-                'paramset': paramset(
-                    n_parameters=2, inits=[0, 0], bounds=[[0, 10], [0, 10]]
+                'paramset': constrained_by_poisson(
+                    n_parameters=2,
+                    inits=[0, 0],
+                    bounds=[[0, 10], [0, 10]],
+                    fixed=False,
+                    auxdata=[None, None],
+                    factors=[None, None],
                 ),
                 'slice': slice(2, 4),
             },
             'dummy2': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': paramset(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(4, 5),
             },
         },
@@ -432,11 +494,15 @@ def test_normfactor(backend):
     mc = MockConfig(
         par_map={
             'mu1': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': unconstrained(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(0, 1),
             },
             'mu2': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': unconstrained(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(1, 2),
             },
         },
@@ -508,18 +574,30 @@ def test_shapesys_zero(backend):
     mc = MockConfig(
         par_map={
             'SigXsecOverSM': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': paramset(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(0, 1),
             },
             'syst': {
-                'paramset': paramset(
-                    n_parameters=5, inits=[0] * 5, bounds=[[0, 10]] * 5
+                'paramset': constrained_by_poisson(
+                    n_parameters=5,
+                    inits=[0] * 5,
+                    bounds=[[0, 10]] * 5,
+                    fixed=False,
+                    auxdata=[None] * 5,
+                    factors=[None] * 5,
                 ),
                 'slice': slice(1, 6),
             },
             'syst_lowstats': {
-                'paramset': paramset(
-                    n_parameters=0, inits=[0] * 0, bounds=[[0, 10]] * 0
+                'paramset': constrained_by_poisson(
+                    n_parameters=0,
+                    inits=[0] * 0,
+                    bounds=[[0, 10]] * 0,
+                    fixed=False,
+                    auxdata=[None] * 0,
+                    factors=[None] * 0,
                 ),
                 'slice': slice(6, 6),
             },
@@ -590,12 +668,17 @@ def test_shapefactor(backend):
     mc = MockConfig(
         par_map={
             'shapefac1': {
-                'paramset': paramset(n_parameters=1, inits=[0], bounds=[[0, 10]]),
+                'paramset': unconstrained(
+                    n_parameters=1, inits=[0], bounds=[[0, 10]], fixed=False,
+                ),
                 'slice': slice(0, 1),
             },
             'shapefac2': {
-                'paramset': paramset(
-                    n_parameters=2, inits=[0, 0], bounds=[[0, 10], [0, 10]]
+                'paramset': unconstrained(
+                    n_parameters=2,
+                    inits=[0, 0],
+                    bounds=[[0, 10], [0, 10]],
+                    fixed=False,
                 ),
                 'slice': slice(1, 3),
             },

tests/test_constraints.py

@@ -141,6 +141,7 @@ def test_batched_constraints(backend):
                     bounds=[[0, 10]],
                     auxdata=[12],
                     factors=[12],
+                    fixed=False,
                 ),
                 'slice': slice(0, 1),
                 'auxdata': [1],
@@ -152,6 +153,7 @@ def test_batched_constraints(backend):
                     bounds=[[0, 10]] * 2,
                     auxdata=[13, 14],
                     factors=[13, 14],
+                    fixed=False,
                 ),
                 'slice': slice(1, 3),
             },
@@ -162,6 +164,7 @@ def test_batched_constraints(backend):
                     bounds=[[0, 10]] * 2,
                     auxdata=[0, 0],
                     sigmas=[1.5, 2.0],
+                    fixed=False,
                 ),
                 'slice': slice(3, 5),
             },
@@ -171,6 +174,7 @@ def test_batched_constraints(backend):
                     inits=[0] * 3,
                     bounds=[[0, 10]] * 3,
                     auxdata=[0, 0, 0],
+                    fixed=False,
                 ),
                 'slice': slice(5, 8),
             },