// Copyright ©2017 The gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gonum

import (
	"math/cmplx"

	"gonum.org/v1/gonum/internal/asm/c128"
)

// Zgerc performs the rank-one operation
//  A += alpha * x * y^H
// where A is an m×n dense matrix, alpha is a scalar, x is an m element vector,
// and y is an n element vector.
func (Implementation) Zgerc(m, n int, alpha complex128, x []complex128, incX int, y []complex128, incY int, a []complex128, lda int) {
	checkZMatrix('A', m, n, a, lda)
	checkZVector('x', m, x, incX)
	checkZVector('y', n, y, incY)

	if m == 0 || n == 0 || alpha == 0 {
		return
	}

	var kx, jy int
	if incX < 0 {
		kx = (1 - m) * incX
	}
	if incY < 0 {
		jy = (1 - n) * incY
	}
	for j := 0; j < n; j++ {
		if y[jy] != 0 {
			tmp := alpha * cmplx.Conj(y[jy])
			c128.AxpyInc(tmp, x, a[j:], uintptr(m), uintptr(incX), uintptr(lda), uintptr(kx), 0)
		}
		jy += incY
	}
}

// Zgeru performs the rank-one operation
//  A += alpha * x * y^T
// where A is an m×n dense matrix, alpha is a scalar, x is an m element vector,
// and y is an n element vector.
func (Implementation) Zgeru(m, n int, alpha complex128, x []complex128, incX int, y []complex128, incY int, a []complex128, lda int) {
	checkZMatrix('A', m, n, a, lda)
	checkZVector('x', m, x, incX)
	checkZVector('y', n, y, incY)

	if m == 0 || n == 0 || alpha == 0 {
		return
	}

	var kx int
	if incX < 0 {
		kx = (1 - m) * incX
	}
	if incY == 1 {
		for i := 0; i < m; i++ {
			if x[kx] != 0 {
				tmp := alpha * x[kx]
				c128.AxpyUnitary(tmp, y[:n], a[i*lda:i*lda+n])
			}
			kx += incX
		}
		return
	}
	var jy int
	if incY < 0 {
		jy = (1 - n) * incY
	}
	for i := 0; i < m; i++ {
		if x[kx] != 0 {
			tmp := alpha * x[kx]
			c128.AxpyInc(tmp, y, a[i*lda:i*lda+n], uintptr(n), uintptr(incY), 1, uintptr(jy), 0)
		}
		kx += incX
	}
}