scalmiss

Purpose

Tests to see if its argument is a scalar missing value.

Format

y = scalmiss(x)

Parameters:

x (NxK matrix) – data

Returns:

y (scalar) – 1 if argument is a scalar missing value, 0 if not.

Examples

clear s;
do until eof(fp);

   y = readr(fp, r);
   y = packr(y);

   if scalmiss(y);
      continue;
   endif;

   s = s +s umc(y);
endo;

In this example the packr() function will return a scalar missing if every row of its argument contains missing values, otherwise it will return a matrix that contains no missing values. scalmiss() is used here to test for a scalar missing returned from packr(). If the test returns true, then the sum step will be skipped for that iteration of the read loop because there were no rows left after the rows containing missings were packed out.

Remarks

scalmiss() first tests to see if the argument is a scalar. If it is not scalar, scalmiss() returns a 0 without testing any of the elements.

To test whether any element of a matrix is a missing value, use ismiss(). scalmiss() will execute much faster if the argument is a large matrix, since it will not test each element of the matrix but will simply return a 0.

An element of x is considered to be a missing if and only if it contains a missing value in the real part. Thus, scalmiss() would return a 1 for complex \(x = . + 1i\), and a 0 for \(x = 1 + .i\).