Record.wrsamp: ignore samps_per_frame when expanded is false.

When the expanded argument to wrsamp is false, we are writing the
d_signal data, which contains one sample per frame by definition.
Therefore, the header file must not claim that the signal files will
contain multiple samples per frame.

The samps_per_frame attribute of the Record object may or may not be
set appropriately for the actual data contained in the Record object;
for example, rdrecord(r, smooth_frames=True) will set samps_per_frame
according to the number of samples per frame in the original record.

Author: Benjamin Moody

wfdb/io/_header.py

@@ -278,7 +278,7 @@ def set_defaults(self):
         for f in sfields:
             self.set_default(f)
 
-    def wrheader(self, write_dir=""):
+    def wrheader(self, write_dir="", expanded=True):
         """
         Write a WFDB header file. The signals are not used. Before
         writing:
@@ -290,6 +290,10 @@ def wrheader(self, write_dir=""):
         ----------
         write_dir : str, optional
             The output directory in which the header is written.
+        expanded : bool, optional
+            Whether the header file should include `samps_per_frame` (this
+            should only be true if the signal files are written using
+            `expanded=True`).
 
         Returns
         -------
@@ -305,6 +309,8 @@ def wrheader(self, write_dir=""):
         # sig_write_fields is a dictionary of
         # {field_name:required_channels}
         rec_write_fields, sig_write_fields = self.get_write_fields()
+        if not expanded:
+            sig_write_fields.pop("samps_per_frame", None)
 
         # Check the validity of individual fields used to write the header
         # Record specification fields (and comments)

wfdb/io/record.py

@@ -924,7 +924,7 @@ def wrsamp(self, expanded=False, write_dir=""):
         """
         # Perform field validity and cohesion checks, and write the
         # header file.
-        self.wrheader(write_dir=write_dir)
+        self.wrheader(write_dir=write_dir, expanded=expanded)
         if self.n_sig > 0:
             # Perform signal validity and cohesion checks, and write the
             # associated dat files.