IZAMAX(3) BLAS routine of NEC Numeric Library Collection IZAMAX(3) NAME IZAMAX - BLAS level one, maximum index function SYNOPSIS INTEGER FUNCTION IZAMAX ( n, x, incx ) INTEGER n, incx DOUBLE COMPLEX x DESCRIPTION IZAMAX searches a double complex vector for the first occurrence of the maximum absolute value. IZAMAX determines the first index i such that |Real(x )|+ |Imag(x ) | = MAX(|Real(x )| + | Imag(x )|): j = 1, ..., n i i j j where x is an element of a double complex vector. j ARGUMENTS n INTEGER. (input) Number of elements to process in the vector to be searched. If n <= 0, these routines return 0. x DOUBLE COMPLEX. (input) Array of dimension (n-1) * |incx| + 1. Array x contains the vector to be searched. incx INTEGER. (input) Increment between elements of x. RETURN VALUES IZAMAX INTEGER. (output) Return the first index of the maximum absolute value of vector x. The vector x has length n and increment incx. NOTES This routine is Level 1 Basic Linear Algebra Subprograms (Level 1 BLAS). When working backward (incx < 0), each routine starts at the end of the vector and moves backward, as follows: x(1-incx * (n-1)), x(1-incx * (n-2)), ..., x(1) The largest absolute value is: ABS (x(1+(index-1) * incx)) when incx > 0 ABS (x(1+(n-index) * |incx|)) when incx < 0 BLAS routine IZAMAX(3)