Error using 'cada/adigatorVarAnalyzer'

[Uday Phutane]

Hello,

I am trying to use Adigator to calculate gradients for an optimization problem using 'fmincon'. After solving a number of parsing problems, I am stuck at a place which gives me the following set of errors:

====================================================

Error using cada/adigatorVarAnalyzer (line 111)
variable 'cadainput7_2' is either an auxiliary or global variable
which was re-assigned to have derivative information - this is not
allowed.

Error in adigatortempfunc1 (line 114)
cadainput7_2 = adigatorVarAnalyzer('cadainput7_2 =
q(:,j-1);',cadainput7_2,'cadainput7_2',0);

Error in adigator (line 539)
FunctionInfo = adigatortempfunc1(FunctionInfo,UserFunInputs);

Error in adigatorGenFiles4Fmincon (line 186)
conout1 = adigator(ConFunName,Inputs,ConD1FileName,opts);

Error in optimize_adi (line 86)
adifuncs = adigatorGenFiles4Fmincon(setup);

====================================================

Could you provide me any hint(s) as to where I can begin to solve this error? I would be happy to provide as much information as possible (except for the source code, apologies in advance).

Thank you very much,
Uday

[Stuart Rogers]

Does your code use conditional statements (like if ... else ... statements) to assign variables?

[Matthew J. Weinstein]

Hi Uday

Sorry for the late reply. I think what is happening is that you are calling a sub-function twice within the same code, one time it is using an auxiliary input (flowed down from either the main function call or a global) and then calling the same function later with a non-auxiliary input.

The algorithm treats these auxiliary variables differently (doesn't turn them into a structure with .f .dx fields) which can mess some things up - it is something I struggled with for awhile and it still isn't very clean. For example, using this function code:

function z = myfun(x,a)

b = mysubfunc(x,a);

c = mysubfunc(x,x);

z = b+c;

end

function y = mysubfunc(x,a)

y = x + a;
end

with this driver:

in = adigatorCreateDerivInput([1 1],'x');
a = adigatorCreateAuxInput([1 1]);
adigator('myfun',{in,a},'myder',adigatorOptions('overwrite',1));

produces a similar error:

Error using cada/adigatorVarAnalyzer (line 111)
variable 'cadainput2_2' is either an auxiliary or
global variable which was re-assigned to have
derivative information - this is not allowed.

Error in adigatortempfunc1 (line 20)
cadainput2_2 = adigatorVarAnalyzer('cadainput2_2 =
x(1);',cadainput2_2,'cadainput2_2',0);

Error in adigator (line 541)
  FunctionInfo =
  adigatortempfunc1(FunctionInfo,UserFunInputs);

Error in test (line 5)
adigator('myfun',{in,a},'myder',adigatorOptions('overwrite',1)); 

You can work around it by just adding a temporary input that does some superfluous operation prior to the first call. For example

function z = myfun(x,a)

tmp = a + 0;

b = mysubfunc(x,tmp);

c = mysubfunc(x,x);

z = b+c;

end

function y = mysubfunc(x,a)

y = x + a;
end

Will get rid of the error as the "tmp" variable will no longer be flagged as auxiliary.

Matt