如何生成随机（IEEE-754 单精度）浮点文件？

Question

In a bash script, I want to generate a file containing IEEE-754 single-precision floating point values (ie not a text file). I want them to have a uniform distribution over some range (which I have as string variables, $min_val and $max_val ; eg -100.0 and 200.0 respectively). I don't care that much about the "quality" of randomness, so anything passable to the naked human eye will do; and I don't want NaNs or infinities.

What's a convenient way to do that? I can't just user random characters from /dev/urandom and such.

Notes:

• You may assume the minimum and maximum and not subnormal.
• Other reasonable assumptions can be made, but please make them explicitly.

Answer 1

My Perl seems to pack floats into the IEEE-754 format.

You may need to change this for endian-ness:

perl -e '
    ($min,$max,$count) = @ARGV;
    print pack "f*", $min + rand($max-$min) for 1..$count;
' $min $max $count > floatfile

For reference:

perl -e 'print pack "f*", Inf, Nan, -118.625, 0.15625' | od -x

gives, on my machine:

0000000 0000 7f80 0000 ffc0 4000 c2ed 0000 3e20
0000020

"f<*" forces little-endian; "f>*" forces big-endian.