Reducing Computation Time
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Hey I have somewhat tricky task of reducing computation time for one line of code in my professor's project. Is there any way to reduce the following code so that it computes at a faster rate (maybe 0.01s), right now the time to beat is 0.08s. The code is as follows:
(32 bit IEEE demultiplexed)
x = hex2float( dec2hex( fread(fid, 1, 'ubit32', 0, 'ieee-be') ))
Basicslly looking for quicker way to convert the binary file to float. If you're not sure, I'm open to specifics suggestions. Also, would it be better if I wrote a code like this in C first and then let matlab read from there? Thank you.
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Jan
le 26 Avr 2012
d = fread(fid, 1, 'uint32', 'ieee-be');
x = hex2float(sprintf('%x', d));
I do not have hex2float. Could you provide some example data? I assume typecast(uint32(d), 'single') will help also, if the format of fread is set accordingly. But without hex2float I cannot test this.
Anyhow, 0.08 sec sounds extremely slow. I assume this is cause by the rest of the code.
4 commentaires
Jan
le 30 Avr 2012
Thanks, Walter. I cannot find it in the FEX: http://www.mathworks.com/matlabcentral/fileexchange/?sort=date_desc_updated&term=hex2float
Plus de réponses (2)
Walter Roberson
le 26 Avr 2012
Is there a reason you are not just using
x = fread(fid, 1, '*float32', 0, 'ieee-be')
Also if you are doing a lot of calculations, it is almost always faster to use fread() to read a number of items at once. (If you stick with going through hex, then dec2hex() can be used on arrays.)
6 commentaires
Jan
le 30 Avr 2012
'ubit32' is very inefficient, when it really splits the reading to 32 bits. 'uint32' reads and processes them in a block.
Dejan Cvijanovic
le 26 Avr 2012
1 commentaire
Jan
le 30 Avr 2012
I'm sure *you* can confirm them. Simply compare the results and to be sure try it with a bunch of random numbers or bit-patterns.
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