MATLAB POLYSPACE 7 Guida di Installazione Scaricare il pdf (Pagina 474)

7 Tuning and Managing M-Files

Message — Code (Original Line Numbers)

Explanation and Updated Code (New

Line Numbers)

24: 'notline' might be growing inside

a loop. Consider preallocating for

speed.

—————————————————

22 nothandle = ~ishandle(hline);

23 for nh = 1:numel(hline)

24 notline(nh) = ~ishandle(hline(nh))

...

When you increase the s ize of an array within

a loop, it is inefficient. Before the loop,

preallocate the array to its maximum size to

improve p erformance. For more information,

see “Preallocating Memory” in the M ATLAB

Programming documentation. In the example,

addanewlinetopreallocate

notline before

the loop.

23 notline = false(size(hline));

24 for nh = 1:numel(hline)

25 notline(nh) = nothandle(nh) ...

24: Use STRCMPI(str1,str2) instead of

using LOWER in a call to STRCMP.

—————————————————

24 notline(nh)=~ishandle(hline(nh)) ||

~strcmp('line',lower(get(hline(nh),

'type')));

While

strcmp

('line',lower(get(hline(nh)'type'))

converts the result of the get function to a

lowercase string before doin g the comparison,

the

strcmpi function ignores the case while

performing the comparison, with advant ag es

thatincludemoreefficiency.Changeline25to

notline(nh) = nothandle(nh) ||

~strcmpi('line',get(hline(nh),'type'));

28: NUMEL(x) is usually faster than

PROD(SIZE(x)).

—————————————————

28 for nl = 1:prod(size(hline))

See the same message and explanation

reported for line 23. Change the line 29 to

for nl = 1:numel(hline)

7-22

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