/*  Maxima tips http://www.cymric.jp/maxima/tips.html */

rowmult(X, n, c) := block([M],
	M:matrix(),
	for i:1 thru length(X) do
		if i=n then M:addrow(M, c*row(X, i))
		else M:addrow(M, row(X, i)),
	M
);
rowadd(X, n, m, c) := block([M],
	M:matrix(),
	for i:1 thru length(X) do
		if i=n then M:addrow(M, c * row(X, m) + row(X, i))
		else M:addrow(M, row(X, i)),
	M
);
rowch(X, m, n) := block([M],
	M:matrix(),
	for i:1 thru length(X) do
		if i=m then M:addrow(M, row(X, n))
		else if i=n then M:addrow(M, row(X, m))
			 else M:addrow(M, row(X, i)),
	M
);

colmult(X, n, c) := block([M],
	M:matrix(),
	for i:1 thru length(transpose(X)) do
		if i=n then M:addcol(M, c*col(X, i))
		else M:addcol(M, col(X, i)),
	M
);
coladd(X, n, m, c) := block([M],
	M:matrix(),
	for i:1 thru length(transpose(X)) do
		if i=n then M:addcol(M, c * col(X, m) + col(X, i))
		else M:addcol(M, col(X, i)),
	M
);
colch(X, m, n) := block([M],
	M:matrix(),
	for i:1 thru length(transpose(X)) do
		if i=m then M:addcol(M, col(X, n))
		else if i=n then M:addcol(M, col(X, m))
			 else M:addcol(M, col(X, i)),
	M
);