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Test values of for nan / infinity

ingo_berg
Beginner
‎09-06-2005 12:03 PM
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Hi,

is there a way to test if an array contains a nan or inf value without explicitely looping over all its elements? Will an isnan(maxval(diff)) or isnan(minval(diff)) do the trick?

All fortran books i have available here do not mention the isnan function at all instead they use ieee_is_nan . Is isnan a nonstandard extension?

What do I use in order to test for +/-inf
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Steven_L_Intel1
Employee
‎09-06-2005 02:18 PM
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isnan is an extension. Not until F2003 is there a standard spelling for this function.

There is inconsistency among implementations about what is done with max and min when one of the values is an "exceptional value". I would not depend on it.

Intel Fortran also supports an FP_CLASS intrinsic, again an extension, which can be used to test for all kinds of IEEE exceptional values.
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