MATLAB: How to make input/output in a function a vector

graderoundingvector

I'm trying to make a grade-rounding function. How do I make sure my function works on each value I type in at once. E.g. the inputvector [7.2,10.3] should give me the outputvector [7,10]

function gradesRounded = roundGrade(grades)
if grades <= -2
    gradesRounded=-3;
elseif grades <1 && grades > -2
    gradesRounded=00;
elseif grades < 3 && grades >=1
    gradesRounded=02;
elseif grades < 5.5 && grades >= 3
    gradesRounded=4;
elseif grades < 8.5 && grades > 5.5
    gradesRounded=7;
elseif grades >= 8.5 && grades < 11
    gradesRounded=10;
elseif grades >= 11
    gradesRounded=12;
end
end

Best Answer

one cycle is missing

function gradesRounded = roundGrade(grades)
gradesRounded=grades;
for k=1:numel(grades)
if grades(k) <= -2
    gradesRounded(k)=-3;
elseif grades(k) <1 && grades(k) > -2
    gradesRounded(k)=00;
elseif grades(k) < 3 && grades(k) >=1
    gradesRounded(k)=02;
elseif grades(k) < 5.5 && grades(k) >= 3
    gradesRounded(k)=4;
elseif grades(k) < 8.5 && grades(k) > 5.5
    gradesRounded(k)=7;
elseif grades(k) >= 8.5 && grades(k) < 11
    gradesRounded(k)=10;
elseif grades(k) >= 11
    gradesRounded(k)=12;
end
end
end

Related Solutions

MATLAB: How to round elements in a vector to pre-defined intervals

Putting Adam's response as an answer instead of a comment, and explaining it in a bit more detail:

In the first and second part of the "if" statement, you have this bit of code

gradesRounded = -3;

instead of this bit of code:

gradesRounded(i) = -3;

which means that you are over-writing your entire vector with a single number, instead of writing to each element of the vector.

MATLAB: Hi, For example If I give input as a= [-2,6,9,-1,11]; , I’m getting a correct output of ans = -3 7 10 0 12, but sometimes for other input vectors, for example a=[-2,7,11,-1,1.4]; I’m getting ans = 2 and many times output are not correct

You're missing the subscript on the case

    elseif rounding(i) >= 1 && rounding(i) <3
      gradesRounded = Exam_Grades(3);

for the assignment and thus the array becomes the one value Exam_Grades(3) or 2.

Unless the assignment called for using such logic, "the Matlab way" would be to use interp1 to interpolate (aka "table lookup") the desired output or even hist to bin the values. Could be just a couple of lines of code total and redefining the Exam_Grades array and breakpoints could then be accomodated with nothing more than a change in data arrays, not have to rewrite the code. As is, you've got all those breakpoints as "magic numbers" buried in the code and changing anything entails a lot of edits with the attendant likelihood of missing something like the above or ending up with overlapping or missing regions, etc.

ADDENDUM Probably shouldn't since it almost certainly is classwork but the histc solution is just two code lines in addition to the two defining data arrays--

>> type roundGrades2
function gradesRounded = roundGrade2(grades)
% Given vector of actual grades return scaled grades corresponding
    Exam_Grades=[-3, 0, 2, 4, 7,10,12];
    BreakPoints=[-3,-1, 1, 3, 5, 8,11];
    [~,ix]=histc(grades,BreakPoints);
    gradesRounded=Exam_Grades(ix);
  end
>> roundGrades2([-2,6,9,-1,11])
ans =
  -3     7    10     0    12
>> roundGrades2([-2,7,11,-1,1.4])
ans =
  -3     7    12     0     2
>>

Will leave as "exercise for the student" the use of interp1 as a lookup function.

Best Answer

Related Solutions

MATLAB: How to round elements in a vector to pre-defined intervals

MATLAB: Hi, For example If I give input as a= [-2,6,9,-1,11]; , I’m getting a correct output of ans = -3 7 10 0 12, but sometimes for other input vectors, for example a=[-2,7,11,-1,1.4]; I’m getting ans = 2 and many times output are not correct

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