zad Options [-]Mat [-]Mat ... Result
By default, all input matrices are added. For example,
zad A B Ccalculates the sum of A and B, and writes the result to C. If a file name is preceeded by a minus sign, this matrix is subtracted. For example,
zad A -B -C Dcalculates $D=A-B-C$. To subtract the first matrix, you must insert an extra "--" before the file names. Otherwise the first argument would be interpreted as a program option. For example, to calculate $C=-A-B$, use
zad -- -A -B CIf a file name starts with "-", preceed the file name by "+" to add, or by "-" to subtract the matrix. If, for example, the second input file is "-B", use the following syntax:
zad A +-B C zad A --B C