Totalview® for HPC User Guide : PART II Debugging Tools and Tasks : Chapter 10 Examining Arrays : Examining and Analyzing Arrays : Filtering Array Data Overview : Filtering for IEEE Values
Filtering for IEEE Values
You can filter IEEE NaN, Infinity, or denormalized floating-point values by specifying a filter in the following form:
operator ieee-tag
The only comparison operators you can use are equal and not equal.
The ieee-tag represents an encoding of IEEE floating-point values, as the following table describes:
IEEE Tag Value
Meaning
$nan
NaN (Not a number), either quiet or signaling
$nanq
Quiet NaN
$nans
Signaling NaN
$inf
Infinity, either positive or negative
$pinf
Positive Infinity
$ninf
Negative Infinity
$denorm
Denormalized number, either positive or negative
$pdenorm
Positive denormalized number
$ndenorm
Negative denormalized number
Figure 156 shows an example of filtering an array for IEEE values. The bottom window in this figure shows how TotalView displays the unfiltered array. Notice the NaNQ, and NaNS, INF, and -INF values. The other two windows show filtered displays: the top window shows only infinite values; the second window only shows the values of denormalized numbers.
 
Figure 156 – Array Data Filtering for IEEE Values
If you are writing an expression, you can use the following Boolean functions to check for a particular type of value:
IEEE Intrinsic
Meaning
$is_denorm(value)
Is a denormalized number, either positive or negative
$is_finite(value)
Is finite
$is_inf(value)
Is Infinity, either positive or negative
$is_nan(value)
Is a NaN (Not a number), either quiet or signaling
$is_ndenorm(value)
Is a negative denormalized number
$is_ninf(value)
Is negative Infinity
$is_nnorm(value)
Is a negative normalized number
$is_norm(value)
Is a normalized number, either positive or negative
$is_nzero(value)
Is negative zero
$is_pdenorm(value)
Is a positive denormalized number
$is_pinf(value)
Is positive Infinity
$is_pnorm(value)
Is a positive normalized number
$is_pzero(value)
Is positive zero
$is_qnan(value)
Is a quiet NaN
$is_snan(value)
Is a signaling NaN
$is_zero(value)
Is zero, either positive or negative