Merge pull request #142 from sns-chops/interp-dos

interpolate method for DOS

.github/workflows/CI.yml

@@ -15,7 +15,7 @@ jobs:
   build-and-test:
     runs-on: ${{ matrix.os }}
     strategy:
-      fail-fast: false
+      fail-fast: true
       matrix:
         os: ["ubuntu-latest"]
         python-version: ["3.7"]
@@ -58,6 +58,7 @@ jobs:
       - name: build / test
         shell: pwsh
         run: |
+          wget --no-check-certificate "https://mcvine.ornl.gov/multiphonon/ARCS_V_annulus.nxs" -O tests/data/ARCS_V_annulus.nxs
           echo $PYTHON_VERSION
           conda install pip pytest pytest-cov python=$PYTHON_VERSION numpy scipy matplotlib histogram ipywe mantid-framework=5
           python setup.py install

multiphonon/dos/__init__.py

@@ -2,4 +2,29 @@
 #
 # Jiao Lin
 
-# End of file 
+def interp(doshist, newE):
+    """compute a new DOS histogram from the given DOS using the new energy array by interpolation
+
+    Parameters
+    ----------
+
+    doshist: histogram
+        input DOS
+
+    newE:numpy array of floats
+        new energy centers in meV
+
+    """
+    import numpy as np, histogram as H
+    try:
+        E = doshist.energy
+    except:
+        E = doshist.E
+    #
+    newS = np.interp(newE, E, doshist.I)
+    newS_E2 = np.interp(newE, E, doshist.E2)
+    Eaxis = H.axis("E", newE, unit='meV')
+    newHist = H.histogram("DOS", [Eaxis], data=newS, errors=newS_E2)
+    return newHist
+
+# End of file

tests/dos/dos_interp_TestCase.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+#
+
+interactive = False
+
+import os, numpy as np, histogram.hdf as hh
+here = os.path.dirname(__file__)
+
+from multiphonon.dos import interp
+
+import unittest
+class TestCase(unittest.TestCase):
+
+    def test1(self):
+        "interp"
+        dos = hh.load(os.path.join(here, 'dos_to_interp.h5'))
+        newE = np.arange(0, 45, 0.5)
+        newdos = interp(dos, newE)
+        expected = hh.load(os.path.join(here, './expected/dos_interped.h5'))
+        np.testing.assert_allclose(newdos.I, expected.I)
+        np.testing.assert_allclose(newdos.E2, expected.E2)
+        return
+    pass  # end of TestCase
+
+
+if __name__ == "__main__":
+    interactive = True
+    unittest.main()
+
+# End of file