Is_Matrix - Texas Instruments TI-89 Developer's Manual

674

is_matrix

Declaration: Boolean is_matrix (EStackIndex i )
Category(ies): Lists and Matrices
Description: Determines whether the expression indexed by i is a matrix.
Inputs: i
Outputs: Returns TRUE if the expression indexed by i is a matrix. Otherwise returns
FALSE.
Assumptions: None
Side Effects: None
On AMS 1.05 and higher.
Availability:
TI-89 / TI-92 Plus
Differences: None
See Also: is_square_matrix
Example:
void push_colnorm (EStackIndex matrix_idx)
/* Pushes the largest of the sums of the absolute values of the
elements in each column of the matrix indexed by matrix_idx.
*/
{ Access_AMS_Global_Variables;
EStackIndex i, j, old_top = top_estack;
if (is_matrix (matrix_idx))
{ if (! can_be_approxed (matrix_idx, TRUE))
ER_THROW (ER_DOMAIN);
i = matrix_idx - 1u;
push0 ();
while (END_TAG != ESTACK (i))
{ j = top_estack;
push_abs (i);
replace_top2_with_sum (j);
i = next_expression_index (i);
}
j = top_estack;
push_max1 (j);
delete_between (old_top, j);
}
else ER_throw( ER_DATATYPE );
}
TI-89 / TI-92 Plus Developer Guide
Appendix A: System Routines — Lists and Matrices
— Index of the top tag of an internally-simplified expression.
Not for Distribution Beta Version January 26, 2001