Floating-point Selection

Returns the result of a floating-point selection operation. This result is determined by comparing the value of X with zero.

**Parameters**

**X**- must be of type
**REAL(4)**or**REAL(8)**.

**Result Type and Attributes**

Same as `X`, `Y` and `Z`.

**Results**

- If the value of
`X`is greater than or equal to zero, then the value of`Y`is returned. - If the value of
`X`is smaller than zero or is a NaN, then the value of`Z`is returned.

A zero value is considered unsigned. That is, both +0 and -0 are equal to zero.