How to generate a matrix of random decimal values from -1 to 1?

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Rachel Dawn 2021-7-27

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评论： Rik 2021-7-27

I want to generate a 8x10 matrix full of random decimal values from -1 to 1, each with EXACTLY 6 decimal places (i.e 0.523483, -0.932401, etc.).

I know that this code generates values with 7 decimal places (not sure how to get it to 6). But, I don't know how to automatically generate a matrix full of values like these (without using a for loop). Any ideas? thanks!

format long 
disp(single(rand(3)))

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Rik 2021-7-27

在 MATLAB Online 中打开

Note that single doesn't have normal decimal places, as it is a floating point number. They take this shape:

(-1)^sign*2^(exponent-127)x1.fraction
%double has -1023 instead of -127

What you want is to round, which might affect the distribution of your values in subbtle and unintuitive ways.

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Answer 1

KSSV 2021-7-27

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https://ww2.mathworks.cn/matlabcentral/answers/886724-how-to-generate-a-matrix-of-random-decimal-values-from-1-to-1#answer_754559

编辑：KSSV 2021-7-27

在 MATLAB Online 中打开

format long 
A = single(rand(3)) ;
fmt = [repmat(' %0.6f',1,3),'\n'];
fprintf(fmt,A)
 0.753020 0.794493 0.884238
 0.019086 0.490358 0.960622
 0.517914 0.845987 0.772295