call variables:
|---------|--------|---------|---------|---------|
| ntype = |iptra = | iptrb = | knum =  | mnum =  |
|---------|--------|---------|---------|---------|
|   c     | iptrc  |  iptrc  |  ncparm |  ncparm |
|---------|--------|---------|---------|---------|
|   f     | iptrc  |  iptrd  |  ncparm |  ndparm |
|---------|--------|---------|---------|---------|
|   d     | iptrd  |  iptrd  |  ndparm |  ndparm |
|---------|--------|---------|---------|---------|

terminology:
jrow, jcol are indices into c,d, or f (depending on ntype)
nused = number of locations used by previous rows of this
subarray