Why is there loss of precision when writing values using CSVWRITE in MATLAB 7.0 (R14)?

I execute the following code to write the value '1.23456789' to my CSV-file, as follows:

csvwrite('filename.csv', [1.23456789])

Upon reading the value back from the file, I see that there is some loss in precision:

val = csvread('filename.csv')

 val =

     1.2346

When I open the "filename.csv" file, it too contains the rounded-off value.

Answer 1

[MathWorks Support Team]

The CSVWRITE function converts numbers to short format before writing them to the file. To preserve precision, use the DLMWRITE function to explicitly set the precision of the data in the CSV-file:

dlmwrite('filename.csv', [1.23456789], 'delimiter', ',', 'precision', 9);