Download User`s Guide for SNOPT Version 7.4 - CCoM

30
SNOPT 7.4 User’s Guide
after the storage limits are known. Here we illustrate the use of snMemA using the same
arrays for snMemA and snOptA. Note that the snMemA arrays are used to store the optional
parameters, and so any temporary arrays must be copied into the final cw, iw, rw arrays in
order to retain the options.
The work arrays must have length at least 500, so we define
ltmpcw = 500
ltmpiw = 500
ltmprw = 500
As with all SNOPT routines, snInit must be called to set default options:
call snInit
&
( iPrint, iSumm, cw, ltmpcw, iw, ltmpiw, rw, ltmprw )
This installs ltmpcw, ltmpiw, ltmprw as the default internal upper limits on the snOptA
workspace (see Total real workspace p. 84). They are used to compute the boundaries
of any user-defined workspace in cw, iw, or rw.
The next step is to call snMemA to obtain mincw, miniw, minrw as estimates of the storage
needed by snOptA:
call
&
(
&
&
snMemA
INFO, nF, n, nxname, nFname, neA, neG,
mincw, miniw, minrw,
cw, ltmpcw, iw, ltmpiw, rw, ltmprw )
The output values of mincw, miniw, minrw may now be used to define the lengths of the
snOptA work arrays:
lencw = mincw
leniw = miniw
lenrw = minrw
These values may be used in f90 or C to allocate the final work arrays for the problem.
One last step is needed before snOptA is called. The current upper limits ltmpcw, ltmpiw,
ltmprw must be replaced by the estimates mincw, miniw, minrw. This can be done using
the option setting routine snSeti as follows:
Errors = 0
! Counts the number of errors
iPrt
= 0
! Suppress print
output
iSum
= 0
! Suppress summary output
call snSeti
&
( ’Total character workspace’, lencw, iPrt, iSum, Errors,
&
cw, ltmpcw, iw, ltmpiw, rw, ltmprw )
call snSeti
&
( ’Total integer
workspace’, leniw, iPrt, iSum, Errors,
&
cw, ltmpcw, iw, ltmpiw, rw, ltmprw )
call snSeti
&
( ’Total real
workspace’, lenrw, iPrt, iSum, Errors,
&
cw, ltmpcw, iw, ltmpiw, rw, ltmprw )
An alternative way is to call snInit again with arguments lencw, leniw, lenrw:
call snInit
&
( iPrint, iSumm, cw, lencw, iw, leniw, rw, lenrw )
However, this has the twin effects of resetting all options to their default values and reprinting the SNOPT banner (unless iPrint = 0 and iSumm = 0 are set for the Print and Summary
files).