What Does the MATLAB Operator <~ Do?

[Eastonc2]

Homework Statement

I have a problem with vectors x and y, where x=[-3,0,0,2,5,8] and y=[-5,-2,0,3,4,10]
The problem asks me to determine z=y<~x
I've searched my book and cannot determine what this operator is telling me to do. Am I supposed to determine the values of y that are not less than x? I enter this exactly as stated into MATLAB and it returns a vector z=[1,1,1,0,0,0] If someone could help me out here, i'd appreciate it.

Homework Equations

The Attempt at a Solution

 

[Mark44]

Homework Statement

I have a problem with vectors x and y, where x=[-3,0,0,2,5,8] and y=[-5,-2,0,3,4,10]
The problem asks me to determine z=y<~x
I've searched my book and cannot determine what this operator is telling me to do. Am I supposed to determine the values of y that are not less than x? I enter this exactly as stated into MATLAB and it returns a vector z=[1,1,1,0,0,0] If someone could help me out here, i'd appreciate it.

Homework Equations

The Attempt at a Solution

~x is the complement of vector x, which evaluates to a new vector with all the signs switched.

z = y < ~ x causes each element of z to be set to 0 or 1 if an element of y is less than the corresponding element in ~x.

From you answer, I'm guessing that the problem is actually z = y <= ~x.

 

[MisterX]

~x is the complement of vector x, which evaluates to a new vector with all the signs switched.

That's not what the ~ operator does in MATLAB. The ~ is for logical negation, which only applies to logical arrays. Any true element becomes a false element and vice versa. If x is not a logical array, I believe it is first converted into one before the negation is applied. Thus "~x" will have a 0 for every non-zero element in x, and a 1 for every element of x equal to zero.

The idea of using the < operator on a logical array seems improper to me.

 

[Mark44]

That's not what the ~ operator does in MATLAB. The ~ is for logical negation, which only applies to logical arrays. Any true element becomes a false element and vice versa. If x is not a logical array, I believe it is first converted into one before the negation is applied. Thus "~x" will have a 0 for every non-zero element in x, and a 1 for every element of x equal to zero.

Your explanation sounds reasonable to me.

The idea of using the < operator on a logical array seems improper to me.

Not to me. You should be able to compare (<, <=, ==, >=, >) two logical values or two arrays of logical values.

In the OP's question, [-5, -2, 0, 3, 4, 10] is being compared to ~x = ~[-3, 0, 0, 2, 5, 8]. Each nonzero entry in ~x is replaced by 1, and each zero entry is replaced by 0, I believe. Then the two arrays are compared, element by element, with the result array having a 1 where y(i) < ~x(i), and a 0 otherwise. That's my best guess, at any rate.

I still have a concern about the 3rd element in the answer that the OP posted. I still believe that in the original problem, the comparison is <=, not <.

 

[DeeNos]

The operator <~ in this context is known as the "not less than" operator. It is used to compare two vectors or arrays and returns a logical vector with 1s for elements that are not less than the corresponding elements in the other vector, and 0s for elements that are less than. In this case, the vector z represents the elements of y that are not less than the corresponding elements in x. So z=[1,1,1,0,0,0] means that for the first three elements, y is not less than x, while for the last three elements, y is less than x. This operator can be useful in various data analysis and sorting applications.