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.

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.

[Stephen23]

Your code does not check if the maximum value can be encoded with that integer class.

Answer 1

[Stephen23]

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:

https://www.mathworks.com/matlabcentral/answers/342027-write-a-function-called-integerize-that-takes-as-its-input-a-matrix-a-of-integers-of-type-double-an

Answer 2

[Tony Mohan Varghese]

Not able to reproduce the error. Please specify the complete error and the types of inputs used.

Answer 3

[RAMAKANT SHAKYA]

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