/* Author: Andrei Zorine
 * delrow(m,i) -- nondestructively deletes the i-th row from the matrix m, 
 *                returns a new matrix
 * delcol(m,i) -- nondestructively deletes the i-th column from the matrix m,
 *                returns a new matrix
 */

delrow(m,i):=block([m1,j],
  if i>1 then(
    m1:row(m,1),
    for j:2 thru i-1 do m1:addrow(m1,row(m,j))),
  if i<length(m) then(
    if symbolp(m1) then(
      m1:row(m,i+1),
      i:i+1),
    for j:i+1 thru length(m) do m1:addrow(m1,row(m,j))),
  m1)$

delcol(m,i):=block([m1,j,sz],
  sz:length(m[1]),
  if i>1 then(
    m1:col(m,1),
    for j:2 thru i-1 do m1:addcol(m1,col(m,j))),
  if i<sz then(
    if symbolp(m1) then(
      m1:col(m,i+1),
      i:i+1),
    for j:i+1 thru sz do m1:addcol(m1,col(m,j))),
  m1)$