 Absolute Value and Matrix - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: Absolute Value and Matrix (/thread-254920.html) Absolute Value and Matrix - BruceTTT - 11-04-2013 What does the absolute value do to a matrix argument? For a 2x2 identity matrix it returns the square root of 2. For [[2,0][0,2]] it returns 2 root 2. Re: Absolute Value and Matrix - Paul Dale - 11-05-2013 Frobenius norm perhaps? Most likely one of the matrix norms. - Pauli Re: Absolute Value and Matrix - Michael de Estrada - 11-05-2013 That's because it returns the Frobenius (Euclidean) norm of the matrix array, which is the square root of the sum of the squares of the matrix elements. So for a 2x2 identity matrix it's sqrt (1^2+1^2) = sqrt (2). In the special case of a 2D or 3D vector, the absolute value is interpreted as the magnitude or length of the vector. Edited: 5 Nov 2013, 12:12 a.m. Re: Absolute Value and Matrix - BruceTTT - 11-11-2013 OK, thanks. Do you mean a 1D vector that || interprets as the norm? I see that [3 4] || returns 5. Also, is there a LIST-> function? Re: Absolute Value and Matrix - Michael de Estrada - 11-11-2013 I meant a vector in 2D or 3D space, where the values are the coordinates. So it's a 1x2 or 1x3 matrix, which is commonly referred to as a vector. Regardless, it is the SRSS (square-root-of-the-sum-of-the-squares). As to your second question I'm not sure what you are asking. Re: Absolute Value and Matrix - Walter B - 11-11-2013 Quote: Do you mean a 1D vector that || interprets as the norm? A 1xn or nx1 matrix is called a vector (of dimension n>1). FYI, a '1D vector' is a (scalar) number. d:-)