Merge pull request #26 from RaphaelRobidas/master

Increased the speed of _transition_matrix_dense twofold
sametz · Dec 8, 2023 · 681749f · 681749f
2 parents b4d4db0 + ec53688
commit 681749f
Show file tree

Hide file tree

Showing 3 changed files with 8 additions and 3 deletions.
diff --git a/.github/workflows/pypi.yml b/.github/workflows/pypi.yml
@@ -70,7 +70,7 @@ jobs:
  name: dist
  path: dist # unmangle to `./dist` to actually publish
 
- - uses: pypa/gh-action-pypi-publish@v1.5.0
+ - uses: pypa/gh-action-pypi-publish@v1.8.5
  with:
  user: __token__
  password: ${{ secrets.PYPI_PASSWORD }}
diff --git a/.github/workflows/test_pypi.yml b/.github/workflows/test_pypi.yml
@@ -70,7 +70,7 @@ jobs:
  name: dist
  path: dist # unmangle to `./dist` to actually publish
 
- - uses: pypa/gh-action-pypi-publish@v1.5.0
+ - uses: pypa/gh-action-pypi-publish@v1.8.5
  with:
  user: __token__
  password: ${{ secrets.TEST_PYPI_PASSWORD }}

diff --git a/src/nmrsim/qm.py b/src/nmrsim/qm.py
@@ -281,7 +281,12 @@ def _transition_matrix_dense(nspins):
  T = np.zeros((n, n))
  for i in range(n - 1):
  for j in range(i + 1, n):
- if bin(i ^ j).count("1") == 1:
+ m = i ^ j
+ # Check if m is a power of two:
+ # If m is a power of two, it will look like 100[...]00 in binary
+ # m-1 will look like 011[...]11 in binary.
+ # Using a binary and, we should then get 0.
+ if m > 0 and m & (m-1) == 0:
  T[i, j] = 1
  T += T.T
  return T