Hi Jeff, I suspect 2-byte integers are not faster to access or compute with then 4-byte floats on modern CPUs. But more of the map will fit into the CPUs cache which could improve bandwidth and could make computing a contour surface faster. But I don't think that will be significant. You would need to test it to know. Chimera keeps the native data type of the map to conserve memory when reading large maps. Tom Jeff wrote:
does this mean that a 2-byte integer format of a file will display faster / render triangles faster than the equivalent sized 4-byte float map?
Thomas Goddard wrote:
Hi Jeff,
Chimera keeps volume data in memory using the same numeric value types that are present in the file, for example, 32-bit float, 16-bit integer, 8-bit integer.
Volume data is copied only when necessary -- for instance, using the Gaussian Filter tool creates a floating point copy of the data since Gaussian convolution of integer data produces a floating point result.
Tom
Jeff wrote:
does chimera store all values as float internally (even if the original map is in 2 byte integers), making the mode of the MRC file irrelevant to chimera's performance?
-jeff