pdf code from diffpy.srfit

news/pdf-pack.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* Add source code from ``diffpy.srfit.pdf`` to ``diffpy.cmipdf``.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

requirements/conda.txt

@@ -1 +1,3 @@
 numpy
+diffpy.srfit
+diffpy.structure

src/diffpy/cmipdf/__init__.py

@@ -4,7 +4,8 @@
 # (c) 2025 Simon Billinge.
 # All rights reserved.
 #
-# File coded by: Caden Myers, Simon Billinge, and members of the Billinge group.
+# File coded by: Caden Myers, Simon Billinge, and members of the Billinge
+#                group.
 #
 # See GitHub contributions for a more detailed list of contributors.
 # https://github.com/diffpy/diffpy.cmipdf/graphs/contributors
@@ -14,9 +15,16 @@
 ##############################################################################
 """The code of the PDF pack of the diffpy.cmi package."""
 
+from diffpy.cmipdf.debyepdfgenerator import DebyePDFGenerator
+from diffpy.cmipdf.pdfcontribution import PDFContribution
+from diffpy.cmipdf.pdfgenerator import PDFGenerator
+from diffpy.cmipdf.pdfparser import PDFParser
+
 # package version
 from diffpy.cmipdf.version import __version__  # noqa
 
+__all__ = ["PDFGenerator", "DebyePDFGenerator", "PDFContribution", "PDFParser"]
+
 # silence the pyflakes syntax checker
 assert __version__ or True
 

src/diffpy/cmipdf/basepdfgenerator.py

@@ -0,0 +1,333 @@
+#!/usr/bin/env python
+##############################################################################
+#
+# (c) 2025 Simon Billinge.
+# All rights reserved.
+#
+# File coded by: Caden Myers, Simon Billinge, and members of the Billinge
+#                group.
+#
+# See GitHub contributions for a more detailed list of contributors.
+# https://github.com/diffpy/diffpy.cmipdf/graphs/contributors
+#
+# See LICENSE.rst for license information.
+#
+##############################################################################
+"""PDF profile generator base class.
+
+The BasePDFGenerator class interfaces with SrReal PDF calculators and is
+used as a base for the PDFGenerator and DebyePDFGenerator classes.
+"""
+
+__all__ = ["BasePDFGenerator"]
+
+import numpy
+
+from diffpy.srfit.exceptions import SrFitError
+from diffpy.srfit.fitbase import ProfileGenerator
+from diffpy.srfit.fitbase.parameter import ParameterAdapter
+from diffpy.srfit.structure import struToParameterSet
+
+# FIXME - Parameter creation will have to be smarter once deeper calculator
+# configuration is enabled.
+
+
+class BasePDFGenerator(ProfileGenerator):
+    """Base class for calculating PDF profiles using SrReal.
+
+    This works with diffpy.structure.Structure, pyobjcryst.crystal.Crystal and
+    pyobjcryst.molecule.Molecule instances. Note that the managed Parameters
+    are not created until the structure is added.
+
+    Attributes
+    ----------
+    _calc
+        PDFCalculator or DebyePDFCalculator instance for calculating
+        the PDF.
+    _phase
+        The structure ParameterSet used to calculate the profile.
+    stru
+        The structure objected adapted by _phase.
+    _lastr
+        The last value of r over which the PDF was calculated. This is
+        used to configure the calculator when r changes.
+    _pool
+        A multiprocessing.Pool for managing parallel computation.
+
+    Managed Parameters
+    ------------------
+    scale
+        Scale factor
+    delta1
+        Linear peak broadening term
+    delta2
+        Quadratic peak broadening term
+    qbroad
+        Resolution peak broadening term
+    qdamp
+        Resolution peak dampening term
+    Managed ParameterSets
+        The structure ParameterSet (SrRealParSet instance) used to
+        calculate the profile is named by the user.
+
+    Usable Metadata
+    ---------------
+    stype
+        The scattering type "X" for x-ray, "N" for neutron (see
+        'setScatteringType').
+    qmax
+        The maximum scattering vector used to generate the PDF (see
+        setQmax).
+    qmin
+        The minimum scattering vector used to generate the PDF (see
+        setQmin).
+    scale
+        See Managed Parameters.
+    delta1
+        See Managed Parameters.
+    delta2
+        See Managed Parameters.
+    qbroad
+        See Managed Parameters.
+    qdamp
+        See Managed Parameters.
+    """
+
+    def __init__(self, name="pdf"):
+        """Initialize the generator."""
+        ProfileGenerator.__init__(self, name)
+
+        self._phase = None
+        self.stru = None
+        self.meta = {}
+        self._lastr = numpy.empty(0)
+        self._calc = None
+
+        self._pool = None
+
+        return
+
+    _parnames = ["delta1", "delta2", "qbroad", "scale", "qdamp"]
+
+    def _setCalculator(self, calc):
+        """Set the SrReal calculator instance.
+
+        Setting the calculator creates Parameters from the variable
+        attributes of the SrReal calculator.
+        """
+        self._calc = calc
+        for pname in self.__class__._parnames:
+            self.addParameter(ParameterAdapter(pname, self._calc, attr=pname))
+        self.processMetaData()
+        return
+
+    def parallel(self, ncpu, mapfunc=None):
+        """Run calculation in parallel.
+
+        Attributes
+        ----------
+        ncpu
+            Number of parallel processes.  Revert to serial mode when 1.
+        mapfunc
+            A mapping function to use. If this is None (default),
+            multiprocessing.Pool.imap_unordered will be used.
+
+        No return value.
+        """
+        from diffpy.srreal.parallel import createParallelCalculator
+
+        calc_serial = self._calc
+        if hasattr(calc_serial, "pqobj"):
+            calc_serial = calc_serial.pqobj
+        # revert to serial calculator for ncpu <= 1
+        if ncpu <= 1:
+            self._calc = calc_serial
+            self._pool = None
+            return
+        # Why don't we let the user shoot his foot or test on single CPU?
+        # ncpu = min(ncpu, multiprocessing.cpu_count())
+        if mapfunc is None:
+            import multiprocessing
+
+            self._pool = multiprocessing.Pool(ncpu)
+            mapfunc = self._pool.imap_unordered
+
+        self._calc = createParallelCalculator(calc_serial, ncpu, mapfunc)
+        return
+
+    def processMetaData(self):
+        """Process the metadata once it gets set."""
+        ProfileGenerator.processMetaData(self)
+
+        stype = self.meta.get("stype")
+        if stype is not None:
+            self.setScatteringType(stype)
+
+        qmax = self.meta.get("qmax")
+        if qmax is not None:
+            self.setQmax(qmax)
+
+        qmin = self.meta.get("qmin")
+        if qmin is not None:
+            self.setQmin(qmin)
+
+        for name in self.__class__._parnames:
+            val = self.meta.get(name)
+            if val is not None:
+                par = self.get(name)
+                par.setValue(val)
+
+        return
+
+    def setScatteringType(self, stype="X"):
+        """Set the scattering type.
+
+        Attributes
+        ----------
+        stype
+            "X" for x-ray, "N" for neutron, "E" for electrons,
+            or any registered type from diffpy.srreal from
+            ScatteringFactorTable.getRegisteredTypes().
+
+        Raises ValueError for unknown scattering type.
+        """
+        self._calc.setScatteringFactorTableByType(stype)
+        # update the meta dictionary only if there was no exception
+        self.meta["stype"] = self.getScatteringType()
+        return
+
+    def getScatteringType(self):
+        """Get the scattering type.
+
+        See 'setScatteringType'.
+        """
+        return self._calc.getRadiationType()
+
+    def setQmax(self, qmax):
+        """Set the qmax value."""
+        self._calc.qmax = qmax
+        self.meta["qmax"] = self.getQmax()
+        return
+
+    def getQmax(self):
+        """Get the qmax value."""
+        return self._calc.qmax
+
+    def setQmin(self, qmin):
+        """Set the qmin value."""
+        self._calc.qmin = qmin
+        self.meta["qmin"] = self.getQmin()
+        return
+
+    def getQmin(self):
+        """Get the qmin value."""
+        return self._calc.qmin
+
+    def setStructure(self, stru, name="phase", periodic=True):
+        """Set the structure that will be used to calculate the PDF.
+
+        This creates a DiffpyStructureParSet, ObjCrystCrystalParSet or
+        ObjCrystMoleculeParSet that adapts stru to a ParameterSet interface.
+        See those classes (located in diffpy.srfit.structure) for how they are
+        used. The resulting ParameterSet will be managed by this generator.
+
+        Attributes
+        ----------
+        stru
+            diffpy.structure.Structure, pyobjcryst.crystal.Crystal or
+            pyobjcryst.molecule.Molecule instance.  Default None.
+        name
+            A name to give to the managed ParameterSet that adapts stru
+            (default "phase").
+        periodic
+            The structure should be treated as periodic (default
+            True). Note that some structures do not support
+            periodicity, in which case this will have no effect on the
+            PDF calculation.
+        """
+
+        # Create the ParameterSet
+        parset = struToParameterSet(name, stru)
+
+        # Set the phase
+        self.setPhase(parset, periodic)
+        return
+
+    def setPhase(self, parset, periodic=True):
+        """Set the phase that will be used to calculate the PDF.
+
+        Set the phase directly with a DiffpyStructureParSet,
+        ObjCrystCrystalParSet or ObjCrystMoleculeParSet that adapts a structure
+        object (from diffpy or pyobjcryst).  The passed ParameterSet will be
+        managed by this generator.
+
+        Attributes
+        ----------
+        parset
+            A SrRealParSet that holds the structural information.
+            This can be used to share the phase between multiple
+            BasePDFGenerators, and have the changes in one reflect in
+            another.
+        periodic
+            The structure should be treated as periodic (default True).
+            Note that some structures do not support periodicity, in
+            which case this will be ignored.
+        """
+        # Store the ParameterSet for easy access
+        self._phase = parset
+        self.stru = self._phase.stru
+
+        # Put this ParameterSet in the ProfileGenerator.
+        self.addParameterSet(parset)
+
+        # Set periodicity
+        self._phase.useSymmetry(periodic)
+        return
+
+    def _prepare(self, r):
+        """Prepare the calculator when a new r-value is passed."""
+        self._lastr = r.copy()
+        lo, hi = r.min(), r.max()
+        ndiv = max(len(r) - 1, 1)
+        self._calc.rstep = (hi - lo) / ndiv
+        self._calc.rmin = lo
+        self._calc.rmax = hi + 0.5 * self._calc.rstep
+        return
+
+    def _validate(self):
+        """Validate my state.
+
+        This validates that the phase is not None. This performs
+        ProfileGenerator validations.
+
+        Raises SrFitError if validation fails.
+        """
+        if self._calc is None:
+            raise SrFitError("_calc is None")
+        if self._phase is None:
+            raise SrFitError("_phase is None")
+        ProfileGenerator._validate(self)
+        return
+
+    def __call__(self, r):
+        """Calculate the PDF.
+
+        This ProfileGenerator will be used in a fit equation that will
+        be optimized to fit some data.  By the time this function is
+        evaluated, the crystal has been updated by the optimizer via the
+        ObjCrystParSet created in setCrystal. Thus, we need only call
+        pdf with the internal structure object.
+        """
+        if not numpy.array_equal(r, self._lastr):
+            self._prepare(r)
+
+        rcalc, y = self._calc(self._phase._getSrRealStructure())
+
+        if numpy.isnan(y).any():
+            y = numpy.zeros_like(r)
+        else:
+            y = numpy.interp(r, rcalc, y)
+        return y
+
+
+# End class BasePDFGenerator