# [TRNSYS-users] Maximum number of Derivatives DTDT array inside one single component ???

Sérgio Casimiro smac at MIT.EDU
Mon Jun 3 08:15:42 PDT 2013

```Hi to all,

I need to solve at least 92 differential equations inside of one TRNSYS
type Im writting with the numerical method that uses the DTDT / T array.
When defining the DTDT and T arrays with more than 50 slots, the TRACE
command will give me a Fatal error while debugging. I already tried to
change the TrnsysConstants.f90 file to assume a higher number of everything
that can be set as a higher number there (including number of derivatives),
but the errors are the same.

If anyone has any tips on how to debug this please tell me something :)

Thanks!

--
Sérgio Casimiro
MIT Portugal  |  Ph.D. Student

------------------------------------------------------------------------------------------------------
Details:

I'm using  TRNSYS 16.1, with CVF 6.6B

1. If I use the TRACE command with more than 60 Derivatives, TRNSYS will
stop saying:  "First-Chance exception in TRNEXE.EXE (TRNDLL.DLL):
0xC000008C: Array Bounds Exceeded"
2. The debugger will stop at Trace.for, line 71  :   10
TF(N)=TI(N)+DELT*DTDT(N)
3. LST file wont say anything relevant for me to correct anything

In my component I got to the point of destroying the whole code I wrote
just to see the sensibility of TRNSYS to this maximum number of derivatives
with the TRACE command. I have set there also the correct Dimensions for
the DTDT and T arrays (in the case of 60 derivatives, their size is 60),
and T=0  and  DTDT=0.

In the deck file I have this:

* START, STOP and STEP
CONSTANTS 3
START=0
STOP=1.000000024
STEP=0.000277778
* User defined CONSTANTS

SIMULATION      START     STOP     STEP    ! Start time    End time    Time
step
TOLERANCES 0.0001 0.0001            ! Integration     Convergence
!>>Adicionei aqui um zero (diminui a tolerancia por uma ordem de grandeza)
LIMITS 84 30 84                ! Max iterations    Max warnings    Trace
limit
DFQ 1                    ! TRNSYS numerical integration solver method
WIDTH 80                ! TRNSYS output file width, number of characters
LIST                     ! NOLIST statement
MAP                     ! MAP statement
SOLVER 0 1 1                ! Solver statement    Minimum relaxation
factor    Maximum relaxation factor
NAN_CHECK 1                ! Nan DEBUG statement
OVERWRITE_CHECK 1            ! Overwrite DEBUG statement
TIME_REPORT 1            ! enable time report statement
EQSOLVER 0                ! EQUATION SOLVER statement
ETRACE START STOP            ! EQUATION TRACE statement

* Model "Type810" (Type 810)
*
UNIT 2 TYPE 810     Type810
*\$UNIT_NAME Type810
*\$MODEL .\My Components\Type810.tmf
*\$POSITION 300 142
*\$LAYER Main #
TRACE START STOP
DERIVATIVES 60
(I have here 60 Zeros's bellow "DERIVATIVES 60" that Im not copying now
here).
*------------------------------------------------------------------------------
END
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