Write a function called integerize that takes as its input a matrix A of integers of type double, and returns the name of the “smallest” signed integer class to which A can be converted without loss of information.

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function text = integerize (A)
minimo = min(min(A));
i8 = intmin('int8'); maxi8 = intmax('int8');
i16 = intmin('int16'); maxi16 = intmax('int16');
i32 = intmin('int32'); maxi32 = intmax('int32');
i64 = intmin('int64'); maxi64 = intmax('int64');
if minimo >= i8 && minimo <= maxi8
text = 'int8';
elseif minimo >= i16 && minimo <= maxi16
text = 'int16';
elseif minimo >= i32 && minimo <= maxi32
text = 'int32';
elseif minimo >= i64&& minimo <= maxi64
text = 'int64';
else
text = 'NONE';
end
My function make an error for argument: A = [128 127; -127 0]. However, if I test it with argument A = -127 is correct.

Accepted Answer

Stephen23
Stephen23 on 21 Mar 2018
Edited: Stephen23 on 21 Mar 2018
A simpler implementation:
function text = integerize(A)
if A >= intmin('int8') & A <= intmax('int8')
typ = 'int8';
elseif A >= intmin('int16') & A <= intmax('int16')
typ = 'int16';
elseif A >= intmin('int32') & A <= intmax('int32')
typ = 'int32';
elseif A >= intmin('int64') & A <= intmax('int64')
typ = 'int64';
else
typ = 'NONE';
end
end
And tested:
>> A = [128,127;-127,0];
>> integerize(A)
ans = int16
int16 is correct because 128 cannot be encoded by int8, but can be by int16 or larger:
>> intmax('int8')
ans = 127
See also this discussion:

More Answers (2)

Tony Mohan Varghese
Tony Mohan Varghese on 21 Mar 2018
Not able to reproduce the error. Please specify the complete error and the types of inputs used.

RAMAKANT SHAKYA
RAMAKANT SHAKYA on 7 Feb 2019
function cls=integerize(a)
if isscalar(a)
if a>0
mina=0;
maxa=a;
else
maxa=0;
mina=a;
end
else
mina=min(a(:));
maxa=max(a(:));
end
if mina>=-2^7 && maxa<=(2^7-1)
cls='int8';
elseif mina>=-2^15 && maxa<=(2^15-1)
cls='int16';
elseif mina>=-2^31 && maxa<=(2^31-1)
cls='int32';
elseif (mina>=-2^63) && maxa<(2^63-1)
cls='int64';
else
cls='NONE';
end
end

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