> Hi,
> I'd like to know the fastest way to do a check on all elements of a
> slice of an array, looking for any occurrence of a particular
> condition. To be precise:
>
> fu(NX,NY,NZ) is an array of derived type, something like
>
> type fu_type
> integer :: bar
> integer :: status
> ...
> end type
>
> type(fu_type) :: fu(NX,NY,NZ)
>
> For a given x, and a status value stat0 I want to determine whether
> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that
> fu(x,y,z)%%status /= stat0
> ...

> Gib Bogle wrote:

>> Hi,
>> I'd like to know the fastest way to do a check on all elements of a
>> slice of an array, looking for any occurrence of a particular
>> condition.  To be precise:

>

>> fu(NX,NY,NZ) is an array of derived type, something like

>

>> type fu_type
>>     integer :: bar
>>     integer :: status
>>     ...
>> end type

>

>> type(fu_type) :: fu(NX,NY,NZ)

>

>> For a given x, and a status value stat0 I want to determine whether
>> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that
>> fu(x,y,z)%%status /= stat0 ...

> On 12 aug, 01:20, Craig Powers wrote:

>> Gib Bogle wrote:

>>> Hi,
>>> I'd like to know the fastest way to do a check on all elements of a
>>> slice of an array, looking for any occurrence of a particular
>>> condition. To be precise:
>>> fu(NX,NY,NZ) is an array of derived type, something like
>>> type fu_type
>>> integer :: bar
>>> integer :: status
>>> ...
>>> end type
>>> type(fu_type) :: fu(NX,NY,NZ)
>>> For a given x, and a status value stat0 I want to determine whether
>>> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that
>>> fu(x,y,z)%%status /= stat0
>>> Is there a clever way to use the ANY intrinsic for this, or do I have to
>>> use dumb loops?

>> How about: ...

> Hi,
> I'd like to know the fastest way to do a check on all elements of a
> slice of an array, looking for any occurrence of a particular
> condition. To be precise:
>
> fu(NX,NY,NZ) is an array of derived type, something like
>
> type fu_type
> integer :: bar
> integer :: status
> ...
> end type
>
> type(fu_type) :: fu(NX,NY,NZ)
>
> For a given x, and a status value stat0 I want to determine whether
> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that
> fu(x,y,z)%%status /= stat0
> ...

> Gib Bogle wrote:

>> Hi,
>> I'd like to know the fastest way to do a check on all elements of a
>> slice of an array, looking for any occurrence of a particular
>> condition. To be precise:
>>
>> fu(NX,NY,NZ) is an array of derived type, something like
>>
>> type fu_type
>> integer :: bar
>> integer :: status
>> ...
>> end type
>>
>> type(fu_type) :: fu(NX,NY,NZ)
>>
>> For a given x, and a status value stat0 I want to determine whether
>> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that
>> fu(x,y,z)%%status /= stat0 ...

> Dick Hendrickson wrote:

>> Gib Bogle wrote:

>>> Hi,
>>> I'd like to know the fastest way to do a check on all elements of a
>>> slice of an array, looking for any occurrence of a particular
>>> condition. To be precise:
>>>
>>> fu(NX,NY,NZ) is an array of derived type, something like
>>>
>>> type fu_type
>>> integer :: bar
>>> integer :: status
>>> ...
>>> end type
>>>
>>> type(fu_type) :: fu(NX,NY,NZ)
>>>
>>> For a given x, and a status value stat0 I want to determine whether
>>> there is any (y,z) 1<=y<=NY, 1<=z<=NZ, such that ...

>>> Depends on what you mean by "fastest". If the condition is an
>>> "unusual" condition, than letting the compiler generate code for the
>>> ANY intrinsic is almost always fastest. If the condition "almost
>>> always" occurs, then a DO loop with a short circuit exit on the first
>>> occurrence is likely to be fastest.

> Then a serious idea popped
> up, try experimenting with FIRSTLOC. That will possibly short-circuit
> the tests when it finds a true instance. But, it's also likely that the
> compiler will generate efficient code (unrolling, pipelined execution,
> whatever) for the implied loop. Again, it will be hardware and compiler
> dependent; but, you might be surprised.

> This prompts me to ask a question that I wondered about, but hadn't
> asked, after seeing your prior post in this thread (quoted above).

> Why wouldn't an optimizing compiler also short-circuit the evaluation of
> the ANY intrinsic? At least for serial architectures, that seems to me
> like the obvious thing to do. (Parallel systems make all kinds of
> questions harder, so I could imagine differences there.) Your first
> quote above sounds to me as though you are assuming that the compiler
> loops through the whole array to implement ANY. I can certainly see that
> as the "obvious" unoptimized solution, but I'd think that a short
> circuit would be a natural candidate for optimization here. Is it just
> that compilers don't tend to optimize those kinds of expressions much at
> all?

> Gib Bogle wrote:

>> Dick Hendrickson wrote:

>>> Gib Bogle wrote:

>>>> Hi,
>>>> I'd like to know the fastest way to do a check on all elements of a
>>>> slice of an array, looking for any occurrence of a particular
>>>> condition. To be precise:
>>>>
>>>> fu(NX,NY,NZ) is an array of derived type, something like
>>>>
>>>> type fu_type
>>>> integer :: bar
>>>> integer :: status
>>>> ...
>>>> end type
>>>>
>>>> type(fu_type) :: fu(NX,NY,NZ)
>>>>
>>>> For a given x, and a status value stat0 I want to determine whether ...