Decimal to Canonical SIgned Digit (CSD) conversion and CSD matrix multilplication with decimal matrix

I got a code which takes an input value and gives the output in Canonical Signed Digit (CSD) form. I took the code from this link: http://www.mathworks.com/matlabcentral/fileexchange/9730-canonical-signed-digits/content/csdigit.m. But i am facing problem when i want to convert all the elements of a matrix in to CSD form. I used following codes in MATLAB:

X = [-7.1989 0.9546; 2.6903 -5.0001];
[rows cols] = size(X);
W = zeros(rows, cols);
for i = 1:rows
    for j = 1: cols                                             
        W(i, j) = csdigit(X(i, j), 4, 10)
    end
end
W   %CSD matrix

But it's showing an error:

??? Subscripted assignment dimension mismatch.

Error in ==> csdmatrix at 6 W(i, j) = csdigit(X(i, j), 4, 10)

How can i remove the error?

Next,i want to perform matrix multiplication in Canonical Signed Digit (CSD) form where A = W*P. Here W is the CSD matrix and P = [0.2597; -5.3109]. Here, each elemant value of P is in fractional decimal form and column size is variable. After performing multiplication of W*P, the resultant matrix A is in decimal form. Please help me in MATLAB coding to perform this multiplication.

Answer 1

[Walter Roberson]

csdigit(X(i, j), 4, 10) probably returns a vector of values (possibly a row vector of characters, also known as a string). You cannot store a vector of numeric values or a multi-character string in a single numeric array location. You will either need to go up one dimension or else switch to a cell array.