Merge pull request #156 from oesteban/fix/auto-lowmem-mode

ENH: Add a memory check to dynamically limit interpolation blocksize

.github/workflows/travis.yml

@@ -50,7 +50,6 @@ jobs:
     - name: Install minimal dependencies
       run: |
         $CONDA/bin/pip install -r min-requirements.txt
-        $CONDA/bin/pip install .
         $CONDA/bin/pip install .[tests]
 
     - uses: actions/cache@v2

sdcflows/interfaces/bspline.py

@@ -227,6 +227,8 @@ class Coefficients2Warp(SimpleInterface):
     output_spec = _Coefficients2WarpOutputSpec
 
     def _run_interface(self, runtime):
+        from ..utils.misc import get_free_mem
+
         # Calculate the physical coordinates of target grid
         targetnii = nb.load(self.inputs.in_target)
         targetaff = targetnii.affine
@@ -237,11 +239,21 @@ def _run_interface(self, runtime):
         weights = []
         coeffs = []
         blocksize = LOW_MEM_BLOCK_SIZE if self.inputs.low_mem else len(points)
+
         for cname in self.inputs.in_coeff:
             cnii = nb.load(cname)
             cdata = cnii.get_fdata(dtype="float32")
             coeffs.append(cdata.reshape(-1))
 
+            # Try to probe the free memory
+            _free_mem = get_free_mem()
+            suggested_blocksize = (
+                int(np.round((_free_mem * 0.80) / (3 * 32 * cdata.size)))
+                if _free_mem
+                else blocksize
+            )
+            blocksize = min(blocksize, suggested_blocksize)
+
             idx = 0
             block_w = []
             while True:

sdcflows/utils/misc.py

@@ -35,3 +35,13 @@ def last(inlist):
     if isinstance(inlist, (list, tuple)):
         return inlist[-1]
     return inlist
+
+
+def get_free_mem():
+    """Probe the free memory right now."""
+    try:
+        from psutil import virtual_memory
+
+        return round(virtual_memory().free, 1)
+    except Exception:
+        return None

sdcflows/utils/tests/test_misc.py

@@ -0,0 +1,21 @@
+"""Test miscellaneous utilities."""
+import sys
+from collections import namedtuple
+import types
+import pytest
+from ..misc import get_free_mem
+
+
+@pytest.mark.parametrize("retval", [None, 10])
+def test_get_free_mem(monkeypatch, retval):
+    """Test the get_free_mem utility."""
+
+    def mock_func():
+        if retval is None:
+            raise ImportError
+        return namedtuple("Mem", ("free",))(free=retval)
+
+    psutil = types.ModuleType("psutil")
+    psutil.virtual_memory = mock_func
+    monkeypatch.setitem(sys.modules, "psutil", psutil)
+    assert get_free_mem() == retval

setup.cfg

@@ -56,6 +56,8 @@ doc =
     sphinxcontrib-versioning
 docs =
     %(doc)s
+mem =
+    psutil
 tests =
     pytest
     pytest-xdist >= 2.0
@@ -64,6 +66,7 @@ tests =
     coverage
 all =
     %(doc)s
+    %(mem)s
     %(tests)s
 
 [options.package_data]